Chafery - A charcoal-fired furnace used in early iron making processes to reheat a bloom of wrought iron for forging to consolidate the iron and expel entrapped slag.

Chamfer - (1) A beveled surface to eliminate an otherwise sharp corner. (2) A relieved angular cutting edge at a tooth corner.

Charcoal Tin Plate - Tin Plate with a relatively heavy coating of tin (higher than the Coke Tin Plate grades).

Charpy Test - A pendulum-type single-blow impact test in which the specimen usually notched, is supported at both ends as a simple beam and broken by a falling pendulum. The energy absorbed, as determined by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.

Chatter Marks - Parallel indentations or marks appearing at right angles to edge of strip forming a pattern at close and regular intervals, caused by roll vibrations.

Chemical Milling - Removing metal stock by controlled selective chemical etching.

Chemical Polishing - Improving the specular reflectivity of a metal surface by chemical treatment.

Chemical Treatment - A substance (chromic acid) that is applied to hot dip galvanize sheet to prevent the formation of white rust during shipping and storage.

Chemistry (of slab) - The chemical composition of the steel that in part determines the physical and mechanical properties of the product.

Chipping - A method for removing seams and other surface defects with chisel or gouge so that such defects will not be worked into the finished product. Chipping is often employed also to remove metal that is excessive but not defective. Removal of defects by gas cutting is known as deseaming or scarfing.

Chromadizing (Chromodizing, Chromatizing) - Forming an acid surface to improve paint adhesion on aluminum or aluminum alloys, mainly aircraft skins, by treatment with a solution of chromic acid.

Chromium – Cr

Atomic Number: 24
Atomic Weight: 51.9961
Melting Point: 2180 K (1907°C or 3465°F)
Boiling Point: 2944 K (2671°C or 4840°F)
Density: 7.15 grams per cubic centimeter
Phase at Room Temperature: Solid

It is of bright silvery color, relatively hard. It is strongly resistant to atmospheric and other oxidation. It is of great value in the manufacture of Stainless Steel as an iron-base alloy. Chromium plating has also become a large outlet for the metal. Its principally functions as an alloy in steel making; (1) increases resistance to corrosion and oxidation (2) increases harden-ability (3) adds some strength at high temperatures (4) resists abrasion and wear (with high carbon). Straight chromium steels are susceptible to temper embrittlement and can be brittle.

Chromium-Nickel Steel - Steel usually made by the electric furnace process in which chromium and nickel participate as alloying elements. The stainless steel of 18% chromium and 8% nickel are the better known of the chromium-nickel types.

Chromizing - A surface treatment at elevated temperature, generally carried out in pack, vapor, or salt bath, in which an alloy is formed by the inward diffusion of chromium into the base metal.

Cigarette Knife Steel - Hardened, tempered and bright polished, 1.25 Carbon content- Chromium .15. Accurate flatness necessary and a high hardness with Rockwell C 51 to 53. Usual sizes are 4 3/4 wide and 6 wide x .004 to .010.

Clad Metal - A composite metal containing two or three layers that have been bonded together. The bonding may have been accomplished by co-rolling, welding, heavy chemical deposition or heavy electroplating.

Cladding - A process for covering one metal with another. Usually the surfaces of fairly thick slabs of two metals are brought carefully into contact and are then subjected to co-rolling so that a clad composition results. In some instances a thick electroplate may be deposited before rolling.

Cleavage - Fracture of a crystal by crack propagation across a crystallographic plane of low index.

Cleavage Fracture - Fracture of a grain, or most of the grains, in a polycrystalline metal by cleavage, resulting in bright reflecting facets.

Cleavage Plane - A characteristic crystallographic plane or set of planes in a crystal on which cleavage fracture occurs easily.

Cluster Mill - A rolling mill where each of the two working rolls of small diameter is supported by two or more back-up rolls.

Cobalt – Co

Atomic Number: 27
Atomic Weight: 58.933200
Melting Point: 1768 K (1495°C or 2723°F)
Boiling Point: 3200 K (2927°C or 5301°F)
Density: 8.86 grams per cubic centimeter
Phase at Room Temperature: Solid

A gray magnetic metal, of medium hardness; it resists corrosion like nickel, which it resembles closely; melting point 2696 (degrees) F.; specific gravity 8.9. It is used as the matrix metal in most cemented carbides and is occasionally electroplated instead of nickel, the sulfate being used as electrolyte. Its principal function as an alloy in tool steel; it contributes to red hardness by hardening ferrite.

Coefficient of Expansion - The ratio of change in length, area, or volume per degree to the corresponding value at a standard temperature.

Cogging - An intermediate rolling process when a hot ingot is reduced to a bloom or slab in a cogging mill.

Coil Breaks - Creases or ridges across a metal sheet transverse to the direction of coiling, occasionally occurring when the metal has been coiled hot and uncoiled cold.

Coil Set or Longitudinal Curl - A lengthwise curve or set found in coiled strip metals following its coil pattern. A departure from longitudinal flatness. Can be removed by roller or stretcher leveling from metals in the softer temper ranges.

Coil Weld - A joint between two lengths of metal within a coil - not always visible in the cold reduced product.

Coils - Coiled flat sheet or strip metal- usually in one continuous piece or length.

Coining - A process of impressing images or characters of the die and punch onto a plane metal surface.

Coke Plate (Hot Dipped Tin Plate) - Standard tin plate, with the lightest commercial tin coat, used for food containers, oil canning, etc. A higher grade is the best cokes, with special cokes representing the best of the coke tin variety. For high qualities and heavier coatings.

Cold Drawing - The process of reducing the cross sectional area of wire, bar or tube by drawing the material through a die without any pre-heating. Cold drawing is used for the production of bright steel bar in round square, hexagonal and flat section. The process changes the mechanical properties of the steel and the finished product is accurate to size, free from scale with a bright surface finish.

Cold Reduced Strip - Metal strip, produced from hot-rolled strip, by rolling on a cold reduction mill.

Cold Reduction - (1) Reduction of metal size, usually by rolling or drawing particularly thickness, while the metal is maintained at room temperature or below the recrystallization temperature of the metal. (2) Reduction of strip thickness through the use of force rather than heat.

Cold Rolled Finish - Finish obtained by cold rolling plain pickled sheet or strip with a lubricant resulting in a relatively smooth appearance.

Cold Rolling - Rolling metal at a temperature below the softening point of the metal to create strain hardening (work-hardening). Same as cold reduction, except that the working method is limited to rolling. Cold rolling changes the mechanical properties of strip and produces certain useful combinations of hardness, strength, stiffness, ductility and other characteristics known as tempers, which see.

Cold Shut - (1) A discontinuity that appears on the surface of cast metal as a result of two streams of liquid meeting and failing to unite. (2) A portion of the surface of a forging that is separated, in part, from the main body of metal by oxide. (3) A condition of brittleness existing in some metals at temperatures below the recrystallization temperature.

Cold Treatment - Exposing steel to suitable subzero temperatures (-85 °C, or -120 °F) for the purpose of obtaining desired conditions or properties such as dimensional or microstructural stability. When the treatment involves the transformation of retained austenite, it is usually followed by tempering.

Cold Work - Permanent strain produced by an external force in a metal below its recrystallization temperature.

Cold Working - Plastic deformation, such as rolling, hammering, drawing, etc., at a temperature sufficiently low to create strain-hardening (work-hardening). Commonly, the term refers to such deformation at normal temperatures.

Columbium - See Niobium Nb

Columnar Structure - A coarse structure of parallel columns of grains, having the long axis perpendicular to the casting surface.

Commercial Bronze - A copper-zinc alloy (brass) containing 90% copper and 10% zinc; used for screws, wire, hardware, etc. Although termed commercial-bronze it contains no tin. It is somewhat stronger than copper and has equal or better ductility.

Commercial Quality Steel Sheet - Normally to a ladle analysis of carbon limit at 0.15 max. A Standard Quality Carbon Steel Sheet.

Compressive Strength - The maximum compressive stress that a material is capable of developing, based on original area of cross section. In the case of a material which fails in compression by a shattering fracture, the compressive strength has a very definite value. In the case of materials which do not fail in compression by a shattering fracture, the value obtained for compressive strength is an arbitrary value depending upon the degree of distortion that is regarded as indicating complete failure of the material.

Constitute - A phase, or combination of phases, that occurs in a characteristic configuration in a microstructure.

Constitutional Diagram - A graphical representation of the temperature and composition limits of phase fields in an alloy system as they actually exist under specific conditions of heating and cooling (synonymous with phase diagram). A constitutional diagram may be, or may approximate, and equilibrium diagram, or may represent metastable conditions or phases. Compare equilibrium diagram.

Continuous Casting - (1) A method of producing blooms, billets and slabs in long lengths using water cooled moulds. The castings are continuously withdrawn through the bottom of the caster whilst the teeming of the metal is proceeding. The need for primary and intermediate mills and the storage and use of large numbers of ingot moulds is eliminated. The continuous casting process is also used in the production of cast iron, aluminum and copper alloys. (2) A casting technique in which the ingot, billet, tube, or other shape is continuously solidified while it is being poured, and the length is not determined by mold dimensions.

Contact Corrosion - When two dissimilar metals are in contact without a protective barrier between them and they are in the presence of liquid, an electrolytic cell is created. The degree of corrosion is dependent on the area in contact and the electro-potential voltage of the metals concerned. The less noble of the metals is liable to be attacked, i.e. zinc will act as a protector of steel in sea water whereas copper or brass will attack the steel in the same environment.

Continuous Furnace - Furnace, in which the material being heated moves steadily through the furnace.

Continuous Phase - In an alloy or portion of an alloy containing more than one phase, the phase that forms the background or matrix in which the other phase or phases are present as isolated volumes.

Continuous Pickling - Passing sheet or strip metal continuously through a series of pickling and washing tanks.

Continuous Strip Mill - A series of synchronized rolling mill stands in which coiled flat rolled metal entering the first pass (or stand) moves in a straight line and is continuously reduced in thickness (not width) at each subsequent pass. The finished strip is recoiled upon leaving the final or finishing pass.

Controlled Atmosphere Furnaces - A furnace used for bright annealing into which specially prepared gases are introduced for the purpose of maintaining a neutral atmosphere so that no oxidizing reaction between metal and atmosphere takes place.

Controlled Rolling - A hot rolling process in which the temperature of the steel is closely controlled, particularly during the final rolling passes, to produce a fine-grain microstructure.

Converter - A furnace in which air is blown through the molten bath of crude metal or matte for the purpose of oxidizing impurities.

Cooling Stresses - Stresses developed by uneven contraction or external constraint of metal during cooling; also those stresses resulting from localized plastic deformation during cooling, and retained.

Copper – Cu

Atomic Number: 29
Atomic Weight: 63.546
Melting Point: 1357.77 K (1084.62°C or 1984.32°F)
Boiling Point: 2835 K (2562°C or 4644°F)
Density: 8.933 grams per cubic centimeter
Phase at Room Temperature: Solid

A characteristically reddish metal of bright luster, highly malleable and ductile and having high electrical and heat conductivity; Universally and extensively used in the arts in brasses, bronzes. Universally used in the pure state as sheet, tube, rod and wire and also as alloyed by other elements and an alloy with other metals. It is used in certain steels to improve resistance to atmospheric corrosion.

Core - In the case of steel this refers to a component that has been case-hardened where the centre is softer than the hard surface layer or case. It can also be applied to the central part of a rolled rimming steel.

Coring - A variation of composition between the center and surface of a unit of structure (such as a dendrite, a grain or a carbide particle) resulting from non-equilibrium growth over a range of temperature.

Corrosion - (1) Gradual chemical or electrochemical attack on a metal by atmosphere, moisture or other agents. (2) Deterioration of a metal by chemical or electrochemical reaction with its environment.

Corrosion Embrittlement - The embrittlement caused in certain alloys by exposure to a corrosive environment. Such material is usually susceptible to the intergranular type of corrosion attack. The severe loss of ductility of a metal resulting from corrosive attack, usually intergranular and often not visually apparent.

Corrosion Fatigue - Effect of the application of repeated or fluctuating stresses in a corrosive environment characterized by shorter life than would be encountered as a result of either their repeated or fluctuating stresses alone or the corrosive environment alone.

Corrugated - As a defect. Alternate ridges and furrows. A series of deep short waves.

Coupon - A piece of metal from which a test specimen is to be prepared - often an extra piece (as on a casting or forging) or a separate piece made for test purposes (such as a test weldment).

Covered Electrode - A filler-metal electrode, used in arc welding, consisting of a metal core wire with a relatively thick covering which provides protection for the molten metal form the atmosphere, improves the properties of the weld metal and stabilizes the arc. The covering is usually mineral or metal powders mixed with cellulose or other binder.

Creep - The flow or plastic deformation of metals held for long periods of time at stresses lower than the normal yield strength. The effect is particularly important if the temperature of stressing is above the recrystallization temperature of the metal. Time-dependent strain occurring under stress. The creep strain occurring at a diminishing rate is called primary creep; that occurring at a minimum and almost constant rate, secondary creep; that occurring at an accelerating rate, tertiary creep.

Creep Limit - (1) The maximum stress that will cause less than a specified quantity of creep in a given time. (2) The maximum nominal stress under which the creep strain rate decreases continuously with time under constant load and at constant temperature. Sometimes used synonymously with creep strength.

Creep Strength - (1) The constant nominal stress that will cause a specified quantity of creep in a given time at constant temperature. (2) The constant nominal stress that will cause a specified creep react at constant temperature.

Crevice Erosion - A type of concentration-cell corrosion; corrosion of a metal that is caused by the concentration of dissolved salts, metal ions, oxygen, or other gases, and such, in crevices or pockets remote from the principal fluid stream, with a resultant building up of differential cells that ultimately cause deep pitting.

Critical Cooling Rate - The minimum rate of continuous cooling just sufficient to prevent undesired transformations. For steel, the slowest rate at which it can be cooled form above the upper critical temperature to prevent the decomposition of austenite at any temperature above the Ms. The limiting rate at which austenite must be cooled to ensure that a particular type of transformation product is formed.

Critical Point(s) - (1) The temperature or pressure at which a change in crystal structure, phase, or physical properties occurs. Same as transformation temperature. (2) In an equilibrium diagram, that specific value of composition, temperature and pressure, or combinations thereof, at which the phases of a heterogeneous systems are in equilibrium. (3) Temperatures at which internal changes or transformations take place within a metal either on a rising or falling temperature.

Critical Range - A temperature range in which an internal change takes place within a metal. Also termed transformation range.

Critical Strain - That strain which results in the formation of very large grains during recrystallization.

Critical Temperature - Synonymous with critical point if pressure is constant.

Crop - The defective ends of a rolled or forged product which are cut off and discarded. Cutting off ends of billets ingots or slabs containing pipe or other defects.

Cropped Head/Tail - Squaring of the strip by use of mechanical shear.

Cross Rolling - (1) The rolling of sheet so that the direction of rolling is changed about 90 (degrees) from the direction of the previous rolling. (2) A (hot) rolling process in which rolling reduction is carried out in a direction perpendicular to, as well as a direction parallel to, the length of the original slab. Rolling at an angle to the long dimension of the metal; usually done to increase width.

Crossbow - Deviation from flat across the strip width.

Cross Direction (in rolled or drawn metal) - The direction parallel to the axes of the rolls during rolling. The direction at right angles to the direction of rolling or drawing.

Crown or Heavy Center - A contour on a sheet or roll where the thickness or diameter increases from edge to center. The difference in strip thickness from center to edge. Increased thickness in the center of metal sheet or strip as compared with thickness at the edge.

Crucible - A ceramic pot or receptacle made of graphite and clay, or clay or other refractory material, and used in the melting of metal. The term is sometimes applied to pots made of cast iron, cast steel or wrought steel.

Crucible Steel - High-carbon steel produced by melting blister steel in a covered crucible. Crucible steel was developed by Benjamin Huntsman in about 1750 and remained in use until the late 1940's.

Cryogenic Applications - Sub-zero temperature applications.

Crystal - (1) A physically homogeneous solid in which the atoms. ions or molecules are arranged in a three-dimensional repetitive pattern. (2) A coherent piece of matter, all parts of which have the same anisotropic arrangement of atom; in metals, usually synonymous with grain and crystallite.

Crystalline - Composed of crystals.

Crystalline Fracture - A fracture of a polycrystalline metal characterized by a grainy appearance. Compare fibrous fracture.

Crystallization - The formation of crystals by the atoms assuming definite positions in a crystal lattice. This is what happens when a liquid metal solidifies. (Fatigue, the failure of metals under repeated stresses, is sometimes falsely attributed to crystallization.)

Cube-Centered - Metallography- (concerning space lattices) - Body-centered cubic. Refers to crystal structure.

Cup Fracture (Cup-and-Cone Fracture) - Fracture, frequently seen in tensile test pieces of a ductile material, in which the surface of failure on one portion shows a central flat area of failure in tension, with an exterior extended rim of failure in shear. A type of fracture in a tensile test specimen which looks like a cup having the exterior portion extended with the interior slightly depressed.

Cupping - The fracture of severely worked rods or wire where one end has the appearance of a cup and the other that of a cone.

Cutting Speed - The linear or peripheral speed of relative motion between the tool and work piece in the principal direction of cutting.

Cyaniding - Surface hardening of an iron-base alloy article or portion of it by heating at a suitable temperature in contact with a cyanide salt, followed by quenching. Introducing carbon and nitrogen into a solid ferrous alloy by holding above Ac1 in contact with molten cyanide of suitable composition. The cyanided alloy is usually quench hardened.

Cyanide Hardening - A process of introducing carbon and nitrogen into the surface of steel by heating it to a suitable temperature in a molten bath of sodium cyanide, or a mixture of sodium and potassium cyanide, diluted with sodium carbonate and quenching in oil or water. This process is used where a thin case and high hardness are required.

DC (Direct Chill) Casting - A continuous method of making ingots or billets for sheet or extrusion by pouring the metal into a short mold. The base of the mold is a platform that is gradually lowered while the metal solidifies, the frozen shell of metal acting as a retainer for the liquid metal below the wall of the mold. The ingot is usually cooled by the impingement of water directly on the mold or on the walls of the solid metal as it is lowered. The length of the ingot

is limited by the depth to which the platform can be lowered; therefore, it is often called semi continuous casting.

Dead Flat - Perfectly flat. As pertaining to sheet, strip or plate. Refer to Stretcher Leveling.

Dead Soft Annealing - Heating metal to above the critical range and appropriately cooling to develop the greatest possible commercial softness or ductility.

Dead Soft Steel - Steel, normally made in the basic open-hearth furnace or by the basic oxygen process with carbon less than 0.10% and manganese in the 0.20-0.50% range, completely annealed.

Dead Soft Temper - Condition of maximum softness commercially attainable in wire, strip, or sheet metal in the annealed state.

Deburring - A method whereby the raw slit edge of metal is removed by rolling or filing.

Decarburization - Removal of carbon from the outer surface of iron or steel, usually by heating in an oxidizing or reducing atmosphere. Water vapor, oxygen and carbon dioxide are strong decarburizers. Reheating with adhering scale is also strongly decarburizing in

action. Loss of carbon from the surface of a ferrous alloy as a result of heating in a medium that reacts with carbon.

Decoration (of dislocations) - Segregation of solute atoms to the line of a dislocation in a crystal. In ferrite, the dislocations may be decorated with carbon or nitrogen atoms.

Deep Drawing - The process of cold working or drawing sheet or strip metal blanks by means of dies on a press into shapes which are usually more or less cup-like in character involving considerable plastic deformation of the metal. Deep-drawing quality sheet or strip steel, ordered or sold on the basis of suitability for deep-drawing

Deformative Bands - Generally, bands in which deformation has been concentrated unhomogeneously.

Degassing Process (In steel making) - Removing gases from the molten metal by means of a vacuum process in combination with mechanical action.

Degenerate Structure - Usually refers to pearlite that does not have an ideally lamellar structure. The degree of degeneracy may vary from slight perturbations in the lamellar arrangement to structures that are not recognizably lamellar.

Degreasing - Removal of grease, oil or other lubricant-type materials by immersion in an effective solvent. Usually are used primarily alkaline cleaners, although an organic solvents are useful.

Delta Iron - Allotropic modification of iron, stable above 2552 (degrees) F. to melting point. It is of body-centered cubic crystal structure.

Dendrite - A crystal that has grown in treelike branching mode. A crystal that has a tree-like branching pattern, being most evident in cast metals slowly cooled through the solidification range.

Dendritic Segregation - Inhomogeneous distribution of alloying elements through the arms of dendrites.

Deoxidation - (1) Removal of oxygen from molten metals by use of suitable chemical agents. (2) Sometimes refers to removal of undesirable elements other than oxygen by the introduction of elements or compounds that readily react with them. In steel sheet, strip, and wire technology, the term refers to heat treatment in a reducing atmosphere, to lessen the amount of scale.

Descaling - It is necessary to remove the scale from hot rolled bars or coil before bright drawing. This is normally carried out by shot blasting or pickling in acid. Other methods of descaling steel products include sand blasting, flame descaling and tumbling.

Deseaming - A process of burning out defective areas on the surface of ingots, blooms or billets. The condition of the surface is such that it can then be rolled or forged into a satisfactory product.

DI (Ideal Diameter) - The diameter of a round steel bar that will harden at the center to a given percent of martensite when subjected to an ideal quench (i.e., Grossman quench severity H=infinity)

Diamond Pyramid Hardness Test - This test, more commonly known as the Vickers test, finds greater use in the laboratory than the workshop. It employs a pyramid shaped diamond with an included angle of 136o which is impressed into the specimen using loads of 5 to 120 kg making a small square impression. This test is used for finished or polished components because the impression can be very small. The diamond pyramid hardness number is obtained from a calculation based on measuring the diagonals of the impressions in the steel.

Die - The term die is most commonly used in tooling, i.e. press tools "punch and die" but there are many other types of die, e.g. thread cutting dies, forming dies, forging dies, die-casting dies, etc. The term when applied to steel often refers to drawing dies through which hot rolled wire and bar are drawn to produce the finish and dimensional accuracy that is required for bright steel.

Die Sinking - Forming or machining a depressed pattern in a die.

Die-Lines - Lines of markings daused on drawn or extruded products by minor imperfections in the surface of the die.

Diffusion - (1) Spreading of a constituent in a gas, liquid or solid, tending to make the composition of all parts uniform. (2) The spontaneous

movement of atoms or molecules to new sites within a material.

Dilatometer - An instrument for measuring the expansion or contraction of a solid metal resulting from heating, cooling, polymorphic changes, etc.

Discoloration - A change in the visual appearance of the material caused by formation of oxides when exposed to contaminating atmosphere, always at elevated temperatures.

Dish - A concave surface departing from a straight line edge to edge. Indicates transverse or across the width.

Dislocation - A linear defect in the structure of a crystal.

Doctor Blade Steel Strip - A hardened and tempered spring steel strip, usually blued, produced from approximately .85 carbon cold rolled spring steel strip specially selected for straightness and good edges. Sometimes hand straightened or straightened by grinding and cur to desired lengths. This product is used in the printing trade as a blade to uniformly remove excess ink (dope) from the rolls; hence its name.

Dolomite - A natural carbonate of calcium and magnesium generally used as a flux in blast furnaces.

Drawing - (1) Forming recessed parts by forcing the plastic flow of metal in dies. (2) Reducing the cross section of wire or tubing by pulling it through a die. (3) A misnomer for tempering.

Drawing Back - Reheating after hardening to a temperature below the critical for the purpose of changing the hardness of the steel.

Draw Quality - More flexible grade of steel.

Dressing of coil - Eliminating any damage or defects from the outer or inner diameter of the coil in preparation for shipping.

Drill Rod - A term given to an annealed and polished high carbon tool steel rod usually round and center less ground. The sizes range in round stock from .013 to 1 1/2 diameter. Commercial qualities embrace water and oil hardening grades. A less popular but nevertheless standard grade is a non-deforming quality. Drill Rods are used principally by machinists and tool and die makers for punches, drills, taps, dowel pins, screw machine parts, small tools, etc.

Drop Forging - A forging made with a drop hammer. An operation in which a metal shape is formed by forcing hot metal into impressions formed in solid blocks of hardened alloy steel, the forging dies. The dies are made in halves, one attached to the rising and falling block of the drop forge and the other to the stationary anvil. Drop forgings are widely used in the automotive industry for crankshafts, stub-axles, gears, etc.

Drop Hammer - A forging hammer than depends on gravity for its force.

Dry Rolled Finish - Finish obtained by cold rolling on polished rolls without the use of any coolant or metal lubricant, of material previously plain pickled, giving a burnished appearance.

Ductile Crack Propagation - Slow crack propagation that is accompanied by noticeable plastic deformation and requires energy to be supplied from outside the body.

Ductility - The ability of a material to deform plastically without fracturing, being measured by elongation or reduction of area in a tensile test, by height of cupping in an Erichsen test or by other means. The property of metals that enables them to be mechanically deformed when cold, without fracture. In steel, ductility is usually measured by elongation and reduction of area as determined in a tensile test.

Duplex - A category of stainless steel with high amounts of chromium and moderate nickel content. The duplex class is so named because it is a mixture of austenitic (chromium-nickel stainless class) and ferritic (plain chromium stainless category) structures. This combination was originated to offer more strength than either of those stainless steels. Duplex stainless steels provide high resistance to stress corrosion cracking (formation of cracks caused by a combination of corrosion and stress) and are suitable for heat exchangers, desalination plants, and marine applications.

Durability - The ability to accept permanent deformation.

Duralumin (obsolete) - The trade name applied to the first aluminum-copper-magnesium type of age-hardenable alloy (17S), which contains nominally 4% Cu, 1/2% Mg. The term is sometimes used to include the class of wrought aluminum-copper-magnesium alloys that harden during aging at room temperature.

Dye Penetrant Inspection - A method for detecting surface porosity or cracks in metal. The part to be inspected is cleaned and coated with a dye which penetrates any flaws that may be present. The surface is wiped clean and coated with a white powder. The powder absorbs the dye held in the defects indicating their location.

Earing - Wavy projections formed at the open end of a cup or shell in the course of deep drawing because of difference in directional properties. Also termed scallop. The formation of scallops (ears) around the top edge of a drawn part caused by differences in the directional properties of the sheet metal used.

Eddy-Current Testing - Nondestructive testing method in which eddy-current flow is induced in the test object. Changes in the flow caused by variations in the object are reflected into a nearby coil or coils for subsequent analysis by suitable instrumentation and techniques.

Edge Filing - A method whereby the raw or slit edges of strip metal are passed or drawn one or more times against a series of files, mounted at various angles. This method may be used for deburring only or filing to a specific contour including a completely rounded edge.

Edge Strain or Edge Breaks - Creases extending in from the edge of the temper rolled sheet.

Edges - Many types of edges can be produced in the manufacture of flat rolled metal products. Over the years the following types of edges have become recognized as standard in their respective fields. . Copper Base Alloys- Slit, Slit and Edge Rolled, Sheared, Sawed, Machined or Drawn . Sheet Steels or Aluminum Sheet- Mill Edge, Slit Edge or Sheared Edge. . Strip Steels and Stainless Strip . No. 1 Edge A- Smooth, uniform, round or square edge, either slit or filed or slit and edge rolled as specified, width tolerance +/- .005. . No. 2 Edge- A natural sound mill edge carried through from the hot rolled band. Has not been slit, filed, or edge rolled. Tolerances not closer than hot-rolled strip limits. . No. 3 Edge - Square, produced by slitting only. Not filed. Width tolerances close. . No. 4 Edge - A round edge produced by edge rolling either from a natural mill edge or from slit edge strip. Not as perfect as No. 1 edge. Width tolerances liberal. . No. 5 Edge - An approximately square edge produced by slitting and filing or slitting and rolling to remove burr. . No. 6 Edge - A square edge produced by square edge rolling, generally from square edge hot-rolled occasionally from slit strip. Width tolerances and finish not as exacting as No. 1 edge.

Edging - The dressing of metal strip edges by rolling, filing or drawing.

Egg-Shaped Coils - Coil that is sagging at the center.

Elastic Limit - The maximum stress to which a material may be subjected without any permanent strain remaining upon

complete release of stress. Maximum stress that a material will stand before permanent deformation occurs

Elastic Strain - Dimensional changes accompanying stress where the original dimensions are restored upon release of the stress.

Elasticity - The property which enables a material to return to its original shape and dimension.

Electocleaning (Electrolytic Brightening) - An anodic treatment. A cleaning, polishing, or oxidizing treatment in which the specimen or work is made the anode in a suitable electrolyte; an inert metal is used as cathode and a potential is applied.

Electric Arc Furnace (EAF) - Steelmaking furnace where scrap is generally 100% of the charge. Heat is supplied from electricity that arcs from the graphite electrodes to the metal bath. Furnaces may be either an alternating current (AC) or direct current (DC). DC units consume less energy and fewer electrodes, but they are more expensive.

Electric Furnace Steel - Steel made in any furnace where heat is generated electrically, almost always by arc. Because of relatively high cost, only tool steels and other high-value steels are made by the electric furnace process.

Electrical Steels - Steels which are characterized by their magnetic properties and are intended for the manufacture of electrical circuits. They are supplied in the form of cold rolled sheet or strip, generally less than 2mm thick and up to 1500mm wide. Grain orientated steels have preferential magnetic properties in the direction of rolling and non- grain orientated steels have similar magnetic properties both transversely and in the direction of rolling.

Electocleaning - (Electrolytic Brightening) An anodic treatment. A cleaning, polishing, or oxidizing treatment in which the specimen or work is made the anode in a suitable electrolyte; an inert metal is used as cathode and a potential is applied.

Electrogalvanized - Zinc plating process whereby the molecules on the positively charged zinc anode attach to the negatively charged sheet steel. The thickness of the zinc coating is readily controlled. By increasing the electric charge or slowing the speed of the steel through the plating area, the coating will thicken.

Electro-Galvanizing - Galvanizing by Electro deposition of zinc on steel.

Electrolytic Tin Plate - Black Plate that has been Tin plated on both sides with commercially pure tin by electrode position.

Electron Beam Microprobe Analyzer - An instrument for selective chemical analysis of a small volume of material. An electron beam bombards the area of interest and x-radiation thereby emitted is analyzed in a spectrometer.

Electroplating - The production of a thin coating of one metal on another by elect deposition. It is very extensively used in industry and is continuing to enlarge its useful functions. Various plated metal and combinations thereof are being used for different purposes, to illustrate: 1. Decorative and protection against corrosion; copper, nickel and chromium . 2. Protection against corrosion; cadmium or zinc . 3. Protection against wear; chromium . 4. Build-up of a part or parts undersize; chromium or nickel . 5. Pate for rubber adhesion; brass . 6. Protection against carburization and for brazing operations....copper and nickel The production of a thin coating of one metal on another by electro-deposition. It is very extensively used in industry and is continuing to enlarge its useful functions. Various plated metals and combinations thereof are being used for different purposes.

Electropolishing - Improving the specular reflectivity of a metal surface by electrochemical dissolution. Method for imparting brilliance to stainless steel by removing a thin layer of the surface akin to a reverse electroplating process without any working of the underlying metal. Also known as bright finishing. The process highlights surface irregularities (i.e. roll grit pattern, pickle matte, scratches, pits and digs). At best, very special processing is required to enhance surface to be electro polished.

Electroslag Refining - A specialized steel making process in which a rolled or a cast ingot in the form of an electrode is re-melted in a water cooled copper mould. The melting is activated by resistive heat generated in a conductive slag. The resulting product has a similar basic chemical composition to the original ingot, but is characterized by high purity and low inclusion content. Typical applications include high integrity components for the aerospace industry.

Elevated Temperature Drawing - A process of drawing steel bars at elevated temperatures (normally 250-300oC) which under optimum conditions produce steels that have higher tensile and yield strengths than those cold drawn with the same degree of reduction.

Elongation - (1) Increase in length which occurs before a metal is fractured, when subjected to stress. This is usually expressed as a percentage of the original length and is a measure of the ductility of the metal. (2) In tensile testing, the increase in the gauge length, measured after fracture of the specimen within the gauge length, usually expressed as a percentage of the original gauge length.

Elongation After Fracture - In tensile testing, the increase in the gauge length measured after fracture of the specimen within the gauge length and usually expressed as a percentage of the original gauge length.

Embossing - Raising or indenting a design in relief on a sheet or strip of metal by passing between rolls of desired pattern.

End-Quench Hardenability Test (Jominy Test) - A laboratory procedure for determining the hardenability of a steel or other ferrous alloy. Hardenability is determined by heating a standard specimen above the upper critical temperature, placing the hot specimen in a fixture so that a stream of cold water impinges on one end, and, after cooling to room temperature is

completed, measuring the hardness near the surface of the specimen at regularly spaced intervals along its length. The data are normally plotted as hardness versus distance from the quenched end.

Endurance Limit - Same as fatigue limit. Maximum alternating stress which a given material will withstand for an indefinite number of times without causing fatigue failure.

Epitaxy - Induced orientation of the lattice of a crystal of a surface deposit by the lattice of the substrate crystal.

Equilibrium Diagram (1) A diagram constructed from thermal and other data showing the limits of composition and temperature within which the various constituents or phases of alloys are stable. (2) A graphical representation of the temperature, pressure and composition limits of phase fields in an alloy system as they exist under conditions of thermo dynamical equilibrium. In condensed systems, pressure is usually considered constant.

Equiaxed Crystals - Crystals, each of which has axes approximately equal in length. These are normally present in the centre of a steel ingot.

Equiaxed Structure - A structure in which the grains have approximately the same dimensions in all directions.

Erichsen Test - A cupping test in which a piece of sheet metal, restrained except at the center, is deformed by a cone-shaped spherical-end plunger until fracture occurs. The height of the cup in millimeters at fracture is a measure of the ductility. Similar to the Olsen Test. Readings are in millimeters.

ERW - Electric Resistance Welding (used in formation of pipe).

Etchant - A chemical solution used to etch a metal to reveal structural details.

Etching - (1) In metallography, the process of revealing structural details by the preferential attack of reagents on a metal surface. (2) Subjecting the surface of a metal to preferential chemical or electrolytic attack to reveal structural details.

Eutectic - A mixture of two or more constituents which solidify simultaneously out of the liquid at a minimum freezing point.

Eutectoid - (1) An isothermal reversible transformation in which a solid solution is converted into two or more intimately mixed solids, the number of solids formed being the same as the number of components in the system. (2) An alloy having the composition indicated by the eutectoid point on an equilibrium diagram. (3) An alloy structure of intermixed solid constituents formed by a eutectoid transformation.

Eutectoid Steel - Steel representing the eutectoid composition of the iron-carbon system, with about 0.80% to 0.83% carbon, the eutectoid temperature being about 1333 (degrees) F. Such steel in the annealed condition consists exclusively of pearlite. Steels with less than this quota of carbon are known as hypo-eutectoid and contain free ferrite in addition to the pearlite. When more carbon is present, the steel is known as hyper-eutectoid and contains free cementite. The presence of certain elements, such as nickel or chromium, lowers the eutectoid carbon content.

Exfoliation - A type of corrosion that progresses approximately parallel to the outer surface of the metal, causing layers of the metal to be elevated by the formation of corrosion product.

Expander Steel - Hardened and tempered, blue polished. Carbon content about 1.00, Chromium .17. Used for the expanders in oil piston rings. Hardness 30 N 70 to 73. Range of sizes run for grooves 3/32 to 1/4 wide with the steel approximately .003 less than the grooves and thickness from .012 to .020.

Extensometer - An apparatus for indicating the deformation of metal while it is subjected to stress.

Extensometer Test - The measurement of deformation during stressing in the elastic range, permitting determination of elastic properties such as properties such as proportional limit, proof stress, yield strength by the offset method and so forth. Requires the use of special

testing equipment and testing procedures such as the use of an extensometer or the plotting of a stress-strain diagram.

Extra Hard Temper - In brass mill terminology, Extra Hard is six B&S numbers hard or 50.15% reduction from the previous annealing or soft stage.

Extra Spring Temper - In brass mill terminology. Extra Spring is ten numbers hard or 68.55% reduction in thickness from the previous annealing or soft stage.

Extrusion - Shaping metal into a chosen continuous form by forcing it through a die of appropriate shape. The production of a section by forcing a billet to flow through a die. Often used for producing complex sections, the process is used with both hot and cold metal. Seamless tubes are produced by forcing a hot billet to flow through a die over a mandrel positioned centrally in the die.

Eye of Coil - The center of the coil as wound.

Face Centered (concerning cubic space lattices) - Having equivalent points at the corners of the unit cell and at the centers of its six faces. A face-centered cubic space lattice is characteristic of one of the close-packed arrangements of equal hard spheres.

Fatigue - The phenomenon leading to fracture under repeated or fluctuating stresses having a maximum value less than the tensile strength of the material. Fatigue fractures are progressive, beginning as minute cracks that grow under the action of the fluctuating stress.

Fatigue Life - The number of cycles of stress that can be sustained prior to failure for a stated test condition.

Fatigue Limit - The maximum stress below which a materiel can presumable endure an infinite number of stress cycles. If the stress is not completely reversed, the value of the mean stress, the minimum stress or the stress ratio should be stated.

Fatigue Strength - The maximum stress that can be sustained for a specified number of cycles without failure, the stress being completely reversed within each cycle unless otherwise stated.

Ferrite - Generally, a solid solution of one or more alloying elements in the bcc polymorph of iron ( -Fe). Specifically, in carbon steels, the interstitial solid solution of carbon in -Fe. A solid solution of one or more elements in body-centered cubic iron. Unless otherwise designated (for instance, as chromium ferrite), the solute is generally assumed to be carbon. On some equilibrium diagrams there are two ferrite regions separated by an austenite area. The lower area is alpha ferrite; the upper, delta ferrite. If there is no designation, alpha ferrite is assumed.

Ferrite Banding - Parallel bands of free ferrite aligned in the direction of working. Sometimes referred to a ferrite streaks.

Ferrite-pearlite Banding - Inhomogeneous distribution of ferrite and pearlite aligned in filaments or plates parallel to the direction of working.

Ferritic Grain Size - The grain size of the ferric matrix of a steel.

Ferroalloy - An alloy of iron with a sufficient amount of some element or elements such as manganese, chromium, or vanadium for use as a means in adding these elements into molten steel.

Ferro-Manganese - An alloy of iron and manganese (80% manganese) used in making additions of manganese to steel or cast-iron. Ferroalloy, An alloy of iron with a sufficient amount of some element or elements such as manganese, chromium, or vanadium for use as a means in adding these elements into molten steel.

Ferrous - Related to iron (derived from the Latin ferrum). Ferrous alloys are, therefore, iron base alloys.

Fiber or Fibre - (1) The characteristic of wrought metal that indicates directional properties. It is revealed by etching a longitudinal section or manifested by the fibrous appearance of a fracture. It is caused chiefly by extension of the constituents of the metal, both metallic and nonmetallic, in the direction of working. (2) The pattern of preferred orientation of metal crystal after a given deformation process. Direction in which metals have been caused to flow, as by rolling, with microscopic evidence in the form of fibrous appearance in the direction of flow.

Fiber Stress - (1) Local stress through a small area (a point or line) on a section where the stress is not uniform, as in a beam under a bending load. (2) Unit stress which exists at any given point in a structural element subjected to load; given as load per unit area.

Fibrous Fracture - A fracture whose surface is characterized by a dull gray or silky appearance.

Filed Edges - Finished edges, the final contours of which are produced by drawing the strip over a series of small steel files. This is the usual and accepted method of dressing the edges of annealed spring steel strip after slitting in cases where edgewise slitting cracks are objectionable or slitting burr is to be removed.

Filler Metal - A third material that is melted concurrently with the parent metal during fusion or braze welding. It is usually, but not necessarily, of different composition from the parent metals.

Finery - A charcoal-fueled hearth furnace used in early processes for converting cast iron to wrought iron by melting and oxidizing it in an air blast, then repeatedly oxidizing the product in the presence of a slag. The carbon oxidizes more rapidly than the iron so that a wrought iron of low carbon content is produced.

Finished Steel - Steel that is ready for the market without further work or treatment. Blooms, billets, slabs, sheet bars, and wire rods are termed semi-finished produced by the in-the-line thermal treatment following electrode position.

Finishing Temperature - The temperature at which hot working is completed.

Firecrack - Raised area on the strip caused by a thermal crack on the work roll surface.

Fish eyes - Areas on a fractured steel surface having a characteristic white crystalline appearance.

Flakes - Short discontinuous internal fissures in ferrous metals attributed to stresses produced by lacalized transformation and decreased solubility of hydrogen during cooling after hot working. In a fractured surface, flakes appear as bright silvery areas; on an etched surface they appear as short discontinuous cracks. Also called shatter cracks and snowflakes.

Flame Annealing - A process of softening a metal by the application of heat from a high-temperature flame.

Flame Hardening - A process of hardening a ferrous alloy by heating it above the transformation range by means of a high-temperature flame, and then cooling as required.

Flapper Valve Steel - An extremely flat, very smooth, very accurate to gage, polished, hardened and tempered spring steel produced from approximately 1.15 carbon. The name is derived from its common and principle usage.

Flare Test - A test applied to tubing, involving a tapered expansion over a cone. Similar to pin expansion test.

Flash - (1) In forging, the excess metal forced between the upper and lower dies. (2) In die casting, the fin of metal which results form leakage between the mating die surfaces. (3) In resistance butt welding, a fin formed perpendicular to the direction of applied pressure.

Flash Welding - A resistance butt welding process in which the weld is produced over the entire abutting surface by pressure and heat, the heat being produced by electric arcs between the members being welded.

Flat Latch Needle Steel - Supplied cold rolled and annealed. Carbon content .85. Supplied both in coil and flat length. Used to make flat latch needles which are used in the manufacture of knitted goods.

Flat Wire - A flat Cold Rolled, prepared edge section up to 1 1/4 wide, rectangular in shape. Generally produced from hot rolled rods or specially prepared round wire by one or more cold rolling operations, primarily for the purpose of obtaining the size and section desired. May also be produced by slitting cold rolled flat metal to desired with followed by edge dressing.

Flow Lines - (1) Texture showing the direction of metal flow during hot or cold working. Flow lines often can be revealed by etching the surface or a section of a metal part. (2) In mechanical metallurgy, paths followed by volume elements of metal during deformation. Always visible to a greater or less degree when a longitudinal section has been subjected to Macro etching, indicating the direction of working or rolling.

Flow Stress - The uni-axial true stress required to cause plastic deformation at a specified value of strain. The shear stress required to cause plastic deformation of solid metals.

Fluting - Kinking or breakage due to curving of metal strip on a radius so small, with relation to thickness, as to stretch the outer surface above its elastic limit. Not to be confused with the specific product, Fluted Tubes.

Flux - (1) In refining, a material used to remove undesirable substances as a molten mixture. It may also be used as a protective covering for molten metal. (2) In welding, a material used to prevent the formation of, or to dissolve and facilitate the removal of, oxides and other undesirable substances.

Foil - Metal in sheet form less than 0.006 in. in thickness.

Folds - Defects caused in metal by continued fabrication of overlapping surfaces.

Forge Welding - Welding hot metal by applying pressure or blows.

Forging - Plastically deforming metal, usually hot, into desired shapes with compressive force, with or without dies.

Fractography - Descriptive treatment of fracture, especially in metals, with specific reference to photographs of the fracture surface. Macrofractography involves photographs at low magnification; microfractography, at high magnification.

Fracture - Surface appearance of metals when broken.

Fracture Test - Breaking a specimen and examining the fractured surface with the unaided eye or with a low-power microscope to determine such things as composition, grain size, case depth, soundness, and presence of defects. Nicking and breaking a bar by means of sudden impact, to enable macroscopic study of the fractured surface.

Fragmentation - The subdivision of a grain into small discrete crystallites outlined by a heavily deformed network of intersecting slip bands as a result of cold working. These small crystals or fragments differ from one another in orientation and tend to rotate to a stable orientation determined by the slip systems.

Free Machining - Pertains to the machining characteristics of an alloy to which an ingredient has been introduced to give small broken chips, lower power consumption, better surface finish, and longer tool life; among such additions are sulfur or lead to steel, lead to brass, lead and bismuth to aluminum, and sulfur or selenium to stainless steel.

Fretting (Fretting Corrosion) - Action that results in surface damage, especially in a corrosive environment, when there is relative motion between solid surfaces in contact under pressure.

Friction Gouges or Scratches - A series of relatively short surface scratches variable in form and severity. Refer to Galling.

Full Annealing (ferrous materials - (1) Annealing a ferrous alloy by austenitizing and then cooling slowly through the transformation range. The austenitizing temperature to hypo-eutectoid steel is usually above Ac3; and for hypereutectoid steel, usually between Ac1 and Ac (cm). Used principally on iron and steel, means heating the metal to about 100 (degrees) F. above the critical temperature range, followed by soaking at this point and slow cooling below the critical temperature. (2) An annealing treatment in which a steel is ausenitized by heating to a temperature above the upper critical temperature (A3 or Acm) and then cooled slowly to room temperature. A typical cooling rate would be 210F/h 100 C/h. Compare normalizing. Use of the term annealing without qualification implies full annealing.

Full Finish Plate - Steel sheet or strip, reduced either hot or cold, cleaned, annealed, and then cold-rolled to a bright finish.

Full Hard Temper - (A) (No. 1 Temper) In low carbon sheet or strip steel, stiff and springy, not suitable for bending in any direction. It is the hardest temper obtainable by hard cold rolling. (B) In Stainless Steel Strip, tempers are based on minimum tensile or yield strength. For Chromium-Nickel grades Full Hard temper is 185,000 TS, 140,000 YS Min. Term also used in connection with copper base alloys and considered synonymous with Hard Temper.

Fusion Welding - Any welding process in which fusion is employed to complete the weld.

Gages - Mfrs. standard numbering systems indicating decimal thicknesses or diameters.

Galling - (1) The damaging of one or both metallic surfaces by removal of particles from localized areas due to seizure during sliding friction. (2) Developing a condition on the rubbing surface of one or both mating parts where excessive friction between high spots results in localized welding with substantial spalling and a further roughening of the surface.

Galvanic Corrosion - Corrosion associated with the current of a galvanic cell consisting of two dissimilar conductors in an electrolyte or two similar conductors in dissimilar electrolytes. Where the two dissimilar metals are in contact, the resulting action is referred to as couple action.

Galvanizing - Coating steel with zinc and tin (principally zinc) for rust proofing purposes. Formerly for the purpose of galvanizing, cut length steel sheets were passed singly through a bath of the molten metal. Today's galvanizing processing method consists of uncoiling and passing the continuous length of successive coils either through a molten bath of the metal termed Hot Dipped Galvanizing or by continuously zinc coating the uncoiled sheet electrolytically- termed Electro-Galvanizing.

Galvanneal Furnace - A furnace which is placed over the strip as it exits the zinc bath for the purpose of producing a fully alloyed iron-zinc coating. The furnace can be gas fired or induction.

Gamma Iron - The form of iron stable between 1670 (degrees) F., and 2550 (degrees) F., and characterized by a face-centered cubic crystal structure.

Gas Welding - Welding with a gas flame.

Gauge - A term for thickness.

GFM - Gyratory Forging Machine - A machine designed to hot forge a cylindrical bar shape while it is turning at speed.

Gilding Metal - A copper-zinc alloy containing 95% copper and 5% zinc. While similar to deoxidized copper in physical properties, it is somewhat stronger and very ductile. It has thermal and electrical conductivity slightly better than half that of electrolytic copper and corrosion resistance comparable to copper.

Grain - A solid polyhedral (or many sided crystal) consisting of groups of atoms bound together in a regular geometric pattern. In mill practice grains are usually studied only as they appear in one plane. (1) (Direction of) Refers to grain fiber following the direction of rolling and parallel to edges of strip or sheets. (2) To bend across the grain is to bend at right angles to the direction of rolling. (3) To bend with the grain is to bend parallel to the direction of rolling. In steel, the ductility in the direction of rolling is almost twice that at right angles to the direction of rolling. An individual crystal in a polycrystalline metal or alloy, including twinned regions or sub-grains if present.

Grain Boundary - Bounding surface between crystals. When alloys yield new phases (as in cooling), grain boundaries are the preferred location for the appearance of the new phase. Certain deterioration, such as season cracking and caustic embrittlement, occur almost exclusively at grain boundaries.

Grain-Boundary Liquidation - An advanced stage of overheating in which material in the region of austenitic grain boundaries melts. Also known as burning.

Grain-Boundary Sulfide Precipitation - An intermediate stage of overheating in which sulfide inclusions are redistributed to the austenitic grain boundaries by partial solution at the overheating temperature and reprecipitation during subsequent cooling.

Grain Coarsening - A heat treatment that produces excessively large austenitic grains.

Grain Flow - Fiber like lines appearing on polished and etched sections of forgings, caused by orientation of the constituents of the metal in the direction of working during forging.

Grain Growth - An increase in metallic crystal size as annealing temperature is raised; growth occurs by invasion of crystal areas by other crystals. An increase in the average size of the grains in polycrystalline metal or alloy, usually a result of heating at elevated temperature.

Grain Size - (1) For metals, a measure of the areas or volumes of grains in a polycrystalline material, usually expressed as an average when the individual sizes are fairly uniform. Grain sizes are reported in terms of grains per unit area or volume, average diameter, or as a grain-size number derived form area measurements. Average diameter of grains in the metal under consideration, or alternatively, the number of grains per unit area. Since increase in grain size is paralleled by lower ductility and impact resistance, the question of general grain size is of great significance. The addition of certain metals affects grain size, for example vanadium and aluminum tend to give steel a fine grain. The ASTM has set up a grain size standard for steels, and the McQuaid-Ehn Test has been developed as a method of measurement. (2) Average diameter of grains in the metal under consideration, or alternatively, the number of grains per unit area. Since increase in grain size is paralleled by lower ductility and impact resistance, the question of general grain size is of great significance. The addition of certain metals affects grain size, for example vanadium and aluminum ten to give steel a fine grain.

Grains - Individual crystals in metals.

Granular Fracture - A type of irregular surface produced when metal fractures, characterized by a rough, grain like appearance as differentiated from a smooth silky, or fibrous, type. It can be sub classified into trans-granular and inter-granular forms.. This type of fracture is frequently called crystalline fracture, but the implication that the metal has crystallized is completely misleading.

Granulated - A coarse grain or pebbly surface condition which becomes evident during drawing.

Granulation - The formation of grains immediately upon solidification.

Graphite - The polymorph of carbon with a hexagonal crystal structure.

Graphitization - Formation of graphite in iron or steel. Primary graphitization refers to formation of graphite during solidification. Secondary graphitization refers to later formation during heat treatment.

Graphitizing - A heating and cooling process by which the combined carbon in cast iron or steel is transformed, wholly or partly, to graphitic or free carbon. Annealing a ferrous alloy in such a way that some or all of the carbon is precipitated as graphite.

Gray Cast Iron - A cast iron that gives a gray fracture due to the presence of flake graphite. Often called gray iron.

Grinding - Removing material from a work piece with a grinding wheel or abrasive belt.

Grinding Cracks - Shallow cracks formed in the surface of relatively hard materials because of excessive grinding heat or the high sensitivity of the material.

Ground Flat Stock - Annealed and pre-ground (to close tolerances) tool steel flats in standard sizes ready for tool room use. These are three common grades; water hardening, oil hardening, and air hardening quality.

Guide - Device for holding the metal in the proper position, during rolling, or slitting.

Guide Scratch - Scratches or marks appearing parallel to edges of cold rolled strip caused by scale or other particles which have become

imbedded in or have adhered to the rolling mill guide. Also applies to similar scratches appearing as a result of slitting.

Gun Drill - A drill, usually with one or more flutes and with coolant passages through the drill body, used for deep hole drilling.

Half Hard Temper - (A) In low carbon cold-rolled strip steel, produced by cold rolling to a hardness next to but somewhat softer than full hard temper. (B) In brass mill terminology, half hard is two B&S numbers hard or 20.70% thickness reduction. (C) In Stainless Steel Strip, Tempers are based on minimum tensile or yield strength. For Chromium-Nickel grades Half-Hard Temper 150,000 T.S., 110,000 Y.S.Min.

Hammer Forging - Forging in which the work is deformed by repeated blows. Compare with press forging.

Hard Chromium Chromium deposited for engineering purposes, such as increasing the wear resistance of sliding metal surfaces, rather than as a decorative coating. It is usually applied directly to basis metal and is customarily thicker than a decorative deposit.

Hard Drawing - Drawing metal wire through a die to reduce cross section and increase tensile strength.

Hard Drawn - Wire or tubing drawn to high tensile strength by a high degree of cold work.

Hard Drawn Spring Steel Wire - A medium high carbon cold drawn spring steel wire. Used principally for cold wound springs.

Hard Temper - (A) (For steel see Full Hard Temper) (B) In brass mill terminology. Hard Temper is four B&S numbers hard or 37.1% reduction.

Hardenability - In a ferrous alloy, the property that determines the depth and distribution of hardness induced by quenching.

Hardened and Tempered Spring Steel Strip - A medium or high carbon quality steel strip which has been subjected to the sequence of heating, quenching and tempering.

Hardening - Increasing hardness by suitable treatment, usually involving heating and cooling. When applicable, the following more specific terms should be used: age hardening, case hardening, flame hardening, induction hardening, precipitation hardening, quench hardening. Any process which increases the hardness of a metal. Usually heating and quenching certain iron base alloys from a temperature either within or above the critical temperature range.

Hardness - Degree to which a metal will resist cutting, abrasion, penetration, bending and stretching. The indicated hardness

of metals will differ somewhat with the specific apparatus and technique of measuring. For details concerning the various types of apparatus used in measuring hardness, See Brinell Hardness, Rockwell Hardness, Vickers Hardness, Scleroscope Hardness. Tensile Strength also is an indication of hardness.

Hardness (indentation) - Resistance of a metal to plastic deformation by indentation. Various hardness tests such as Brinell, Rockwell and Vickers may be used. In the Vickers test, a diamond pyramid with an included face angle of 136 is used as the indenter.

Heat of Steel - The product of a single melting operation in a furnace, starting with the charging of raw materials and ending with the tapping of molten metal and consequently identical in its characteristics.

Heat Number - The identification that describes the origin of the slab (heat).

Heat Tinting - Coloration of a metal surface through oxidation by heating to reveal details of structure.

Heat Treatment - Altering the properties of a metal by subjecting it to a sequence of temperature changes, time of retention at specific temperature and rate of cooling all being as important as the temperature itself. Heat treatment usually markedly affects strength, hardness, ductility, malleability, and similar properties of both metals and their alloys. Heating and cooling a solid metal or alloy in such a way that desired structures, conditions or properties are attained. Heating for the sole purpose of hot working is excluded from the meaning of this term.

Heat-Affected Zone - That portion of the base metal which was not melted during brazing, cutting, or welding, but whose microstructure and physical properties were altered by the heat.

Hematite - The oxide of iron of highest valency which has a composition close to the stoichiometric composition Fe2O3.

High Brass - 65% A copper-zinc alloy containing 35% zinc. Possesses high tensile strength. Used for springs, screws, rivets, etc.

HNX Gas - A mixture of hydrogen and Nitrogen gas used to prevent oxidation and to "clean" the strip during the annealing process

Homogenizing - (1) Holding at high temperature to eliminate or decrease chemical segregation by diffusion. (2) An annealing treatment carried out at a high temperature, approaching the solidus temperature, for a sufficiently long time that inhomogeneous distributions of alloying elements are reduced by diffusional processes.

Honing - Removing stock generally on the internal cylindrical surface of a workpiece with an abrasive stick mounted in a holder.

Hooke's Law - Stress is proportional to strain in the elastic range. The value of the stress at which a material ceases to obey Hooke's law is known as the elastic limit.

Hot Dip - In steel mill practice, a process whereby ferrous alloy base metals are dipped into molten metal, usually zinc, tin, or terne, for the purpose of fizing a rust resistant coating.

Hot Rolled Finish - A dark relatively rough oxidized finish resulting from rolling the metal while hot. May subsequently be pickled or bright dipped but the rough surface remains.

Hot Short (Shortness) - Brittleness in hot metal in the hot forming range.

Hot Top - (1) A reservoir, thermally insulated or heated, to hold molten metal on top of a mold to feed the ingot or casting as it contracts on solidifying to avoid having pipe or voids.

Hot Working - Plastic deformation of metal at a temperature sufficiently high not to create strain hardening. The lower limit of temperature for this process is the re-crystallization temperature.

Hydrogen Embrittlement - (1) Brittleness of metal, resulting from the occlusion of hydrogen (usually as a by-product of pickling or by co-deposition in electroplating). (2) A condition of low ductility resulting from hydrogen absorption and internal pressure developed subsequently. Electrolytic copper exhibits similar results when exposed to reducing atmosphere at elevated temperatures.

Hypereutectoid Alloy - In a eutectoid system, any alloy containing more than the eutectoid concentration of solute.

Hypereutectoid Steel - A steel having more than the eutectoid percentage of carbon.

Idiomorphz - A particle of a phase the has a regular external shape.

Immersed Scanning - In ultrasonics, a planned, systematic movement of the beam relative to the object being inspected, the search unit being coupled to this object through a column of liquid. In most cases the object and the search unit are submerged in water.

Impact Energy (Impact Value) - The amount of energy required to fracture a material, usually measured by means of an Izod or Charpy test. The type of specimen and testing conditions affect the values and therefore should be specified.

Impact Test - Test designed to determine the resistance of metal to breakage by impact, usually by concentrating the applied stress to a notched specimen. A test to determine the behavior of materials when subjected to high rates of loading, usually in bending, tension, or torsion. The quantity measured is the energy absorbed in breaking the specimen by a single blow, as in the Charpy or Izod.

Impurities - Elements or compounds whose presence in a material is undesired.

Inclusions - Particles of impurities (usually oxides, sulfides, silicates, etc.) that are held mechanically or are formed during the solidification or by subsequent reaction within the solid metal. A nonmetallic material in a solid metallic matrix.

Indentation Hardness - The resistance of a material to indentation. This is the usual type osf hardness test, in which a pointed or rounded indenter is pressed into a surface under a substantially static load.

Induction Hardening - A process of hardening a ferrous alloy by heating it above the transformation range by means of electrical induction, and then cooling as required. Quench hardening in which the heat is generated by electrical induction.

Induction Heating - A process of heating by electrical induction.

Inert-Gas Shielded-Arc Welding - Arc welding in an inert gas such as argon or helium.

Ingot - A casting suitable for hot working or remelting.

Ingot Iron - Commercially pure open-hearth iron.

Inhibitor - A substance which retards some specific chemical reaction. Pickling inhibitors retard the sissolution of metal without hindering the removal of scale from steel.

Intercrystalline - Between crystals, or between grains. Same as inter-granular.

Interleaving - The placing of a sheet of paper between two adjacent layers of metal to facilitate handling and shearing of rectangular sheets, or to prevent sticking or scratching.

Intermediate Annealing - An annealing treatment given to wrought metals following cold work hardening for the purpose of softening prior to further cold working.

Internal Oxidation - Formation of oxides beneath the surface of a metal.

Interrupted Aging - The aging of an alloy at two or more temperatures by steps, and cooling to room temperature after each step. Compare with progressive aging.

Interrupted Quenching - Quenching in which the metal object being quenched is removed from the quenching medium while the object is at a temperature substantially higher than that of the quenching medium.

Interstitial Solid Solution - A solid solution in which the solute atoms occupy (interstitial) positions between the atoms in the structure of the solvent.

Intracrystalline - Within or across crystals or grains. Same as transcrystalline and transgranular.

Investment Casting - (1) Casting metal into a mold produced by surrounding (investing) an expendable pattern with a refractory slurry that sets at room temperature after which the wax, plastic, or frozed mercury pattern is removed through the use of heat. Also called precision casting, or lost-wax process. (2) A casting made by the process.

Iron – Fe

Atomic Number: 26
Atomic Weight: 55.845
Melting Point: 1811 K (1538°C or 2800°F)
Boiling Point: 3134 K (2861°C or 5182°F)
Density: 7.874 grams per cubic centimeter
Phase at Room Temperature: Solid

A magnetic silver white metal of high tensile strength, ductile and malleable. Chemically iron is chiefly base forming. The principal forms of commercial iron are steel, cast iron and wrought iron. An element that has an average atomic number of 55.85 and that always, in engineering practice, contains small but significant amounts of carbon. Thus iron-carbon alloys containing less than about 0.1% C may be referred to as irons. Alloys with higher carbon contents are always termed steels.

Ironing - Thinning the walls of deep drawn articles by reducing the clearance between punch and die.

Isothermal Annealing - A process in which a ferrous alloy is heated to produce a structure partly or wholly austenitic, and is then cooled to and held at a temperature that causes transformation of the austenite to a relatively soft ferrite-carbide aggregate.

Isothermal Transformation - A change in phase at any constant temperature.

Isothermal Transformation (IT) Diagram - A diagram that shows the isothermal time required for transformation of austenite to commence and to finish as a function of temperature. Same as time-temperature-transformation (TTT) diagram or S-curve.

Izod Test - A pendulum type of single-blow impact test in which the specimen, usually notched, is fixed at one end and broken by a falling pendulum. The energy absorbed, as measured by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.

Jig Saw Steel - Hardened, tempered and bright polished with round edges. Carbon content .85. Ranges of sizes .039 to 393 in width and .016 to .039 in thickness.

Killed Steel - The term killed indicates that the steel has been sufficiently deoxidized to quiet the molten metal when poured into the ingot mold. The general practice is to use aluminum ferrosilicon or manganese as deoxidizing agents. A properly killed steel is more uniform as to analysis and is comparatively free from aging. However, for the same carbon and manganese content Killed Steel is harder than Rimmed Steel. In general all steels above 0.25% carbon are killed, also all forging grades, structural steels from 0.15% to 0.25% carbon and some special steels in the low carbon range. Most steels below 0.15% carbon are rimmed steel. Steel deoxidized with a strong deoxidizing agent, such as silicon or aluminum, to reduce the oxygen content to such a level that no reaction occurs between carbon and oxygen during solidification.

Kind Band (deformation) - In polycrystalline materials, a volume of crystal that has rotated physically to accommodate differential deformation between adjoining parts of a grain while the band itself has deformed homogeneously. This occurs by regular bending of the slip lamellae along the boundaries of the band.

Kip - A load of 1000 lbs.

Ladle Analysis - A term applied to the chemical analysis representative of a heat of steel as reported by the producer. It is determined by analyzing a test ingot sample obtained during the pouring of the steel from a ladle.

Lamellar Tear - A system of cracks or discontinuities aligned generally parallel to the worked surface of a plate. Usually associated with a fusion weld in thick plate.

Laminations - Metal defects with separation or weakness generally aligned parallel to the worked surface of the metal. May be the result of pipe, blisters, seams, inclusions, or segregation elongated and made directional by working. Lamination defects may also occur in metal-powder compacts. An abnormal structure resulting in a separation or weakness aligned generally parallel to the worked surface of the metal.

Lap - A surface defect, appearing as a seam, caused by fording over hot metal, fins, or sharp corners and then rolling or forging them into the surface, but not welding them.

Lap-Weld - A term applied to a weld formed by lapping two pieces of metal and then pressing or hammering, and applied particularly to the longitudinal joint produced by a welding process for tubes or pipe, in which the edges of the skelp are beveled or scarfed so that when they are overlapped they can be welded together.

Lath Martensite - Martensite formed, partly in steel containing less than about 1.0% C and solely in steels containing less than about 0.5% C, as parallel arrays or packets of lath-shape units about 0.1 to 0.3 m thick, and having a habit plane that is close to {111}.

Lattice - Space lattice. Lattice lines and lattice planes are lines and planes chosen so as to pass through collinear lattice points, and non-collinear lattice points, respectively.

LEAD – Pb

Atomic Number: 82
Atomic Weight: 207.2
Melting Point: 600.61 K (327.46°C or 621.43°F)
Boiling Point: 2022 K (1749°C or 3180°F)
Density: 11.342 grams per cubic centimeter
Phase at Room Temperature: Solid

Improves machinability. It does not dissolve in steel but stays as globules. Environmental concerns are resulting in a decreased usage of lead in the steel industry.

Leveling - A mechanical process in which the strip is stretched beyond its yield point by bending over small diameter rolls. The purpose is to improve the flatness of characteristics of the strip.

Light Metal - One of the low-density metals such as aluminum, magnesium, titanium, beryllium, or their alloys.

Liquation - Partial melting of an alloy.

Liquidus - In a constitutional diagram, the locus of points representing the temperatures at which various components commence freezing on cooling or finish melting on heating.

Lithographic Sheet Aluminum - Sheet having a superior surface on one side with respect to freedom from surface imperfections and supplied with a maximum degree of flatness, for use as a plate in offset printing.

Long Terne - A term applying to steel sheets that have been terne coated (Lead and Tin) by immersion in a bath of Terne Metal.

Longitudinal Direction - The principal direction of flow in a worked metal.

Low Brass - 80% cu. A copper-Zinc alloy containing 20% zinc. Is a light golden color, very ductile, suitable for cupping, drawing, forming, etc. Because of its good strength and corrosion resistance it is used for flexible metal hose, metal bellows, etc.

Low Carbon Steels - Contain from 0.10 to 0.30% carbon and less than 0.60% manganese. (The product of Basic Oxygen, Bessemer, Open Hearth or Electric Processes.)

Low-Hydrogen Electrode - A covered arc-welding electrode that provides an atmosphere around the arc and molten weld metal which is low in hydrogen.

Luders Lines (Steel) - (Characteristic of No. 5 Yemper-Not a defect in No. 5 dead soft temper.) Long vein-like marks appearing on the surface of certain metals, in the direction of the maximum shear stress, when the metal is subjected to deformation beyond the field point.

M B Grade - A term applied to Open-Hearth steel wire in the .45/.75 carbon range either hard drawn or oil tempered. Oil tempered wire of M B and W M B types are the most widely used of all spring wires. Oil tempered wire is more suitable to precision forming and casting operations than hard drawn wire, because of close control of tensile strength and superior straightness. . NOTE M B, H B and extra H B designate Basic Open Hearth steels, while W M B, W H B and extra W H B designate Acid Open Hearth Steels. The chemical composition and the mechanical properties are the same for both basic and acid steel.

Machinability - This is a generic term for describing the ability of a material to be machined. To be meaningful, machinability must be qualified in terms of tool wear, tool life, chip control, and/or surface finish and integrity. Overall machining performance is affected by a myriad of variables relating to the machining operation and the workpiece. An overall review is provided in the ASM Metals Handbook: Machinability, Ninth Edition, Volume 16, 1989.

Machinability Index - A relative measure of the machinability of an engineering material under specified standard conditions.

Macro-Etch - Etching of a metal surface for accentuation of gross structural details and defects for observation by the unaided

eye or at magnifications not exceeding ten diameters.

Macroetch Test - Consists of immersing a carefully prepared section of the steel in hot acid and of examining the etched surface to evaluate the

soundness and homogeneity of the product being tested.

Macrograph - A photographic reproduction of any object that has not been magnified more than ten times. A graphic reproduction of a prepared surface of a specimen at a magnification not exceeding ten diameters. When photographed, the reproduction is known as a photomacrograph (not a macrophotograph).

Macroscopic - Visible either with the naked eye or under low magnification (as great as about ten diameters.

Macrostructure - The structure of metals as revealed by examination of the etched surface of a polished specimen at a magnification not exceeding ten diameters.

Magnetic-Particle Inspection - A nondestructive method of inspection for determining the existence and extent of possible defects in ferromagnetic materials. Finely divided magnetic particles, applied to the magnetized part, are attracted to and outline the pattern of any magnetic-leakage fields created by discontinuities.

Magnetite - The oxide or iron of intermediate valence which has a composition close to the stoichiometric composition Fe3O4.

Malleability - The property that determines the ease of deforming a metal when the metal is subjected to rolling or hammering. The more malleable metals can be hammered or rolled into thin sheet more easily than others.

Malleabilizing - A process of annealing white cast iron in such a way that the combined carbon is wholly or partly transformed to graphitic or free carbon or, in some instances, part of the carbon is removed completely.

Manganese – Mn

Atomic Number: 25
Atomic Weight: 54.938049
Melting Point: 1519 K (1246°C or 2275°F)
Boiling Point: 2334 K (2061°C or 3742°F)
Density: 7.3 grams per cubic centimeter
Phase at Room Temperature: Solid

Lustrous, reddish-white metal of hard brittle and, therefore, non-malleable character. The metal is used in large quantities in the form of Spiegel and Ferromanganese for steel manufacture as well as in manganese and many copper-base alloys. Its principal function is as an alloy in steel making: (1) It is ferrite-strengthening and carbide forming element. It increases hardenability inexpensively, with a tendency toward embrittlement when too high carbon and too high manganese accompany each other. (2) It counteracts brittleness from sulfur. It is important because it deoxidizes the melt and facilitates hot working of the steel by reducing the susceptibility to hot shortness. It combines with sulfur to form MnS stringers which increases machinability. Manganese contributes to the effectiveness of normalizing for strengthening, to the formation of fine pearlite, and lowers the Ms temperature, therefore increasing the probability of retained austenite.

Manual Welding - Welding where in the entire welding operation is performed and controlled by hand.

Martempering - (1) A hardening procedure in which an austenitized ferrous material is quenched into an appropriate medium at a temperature just above the Ms temperature of the material, held in the medium until the temperature is uniform through-out -but not long enough for bainite to form - and then cooled in air. The treatment is frequently followed by tempering. (2) When the process is applied to carburized material, the controlling Ms temperature is that of the case. This variation of the process is frequently called marquenching. Quenching an austenitized ferrous alloy in a medium at a temperature in the upper part of the martensite range, or slightly above that range, and holding it in the medium until the temperature throughout the alloy is substantially uniform. The alloy is then allowed to cool in air through the martensite range.

Martensite - (1) In an alloy, a metastable transitional structure intermediate between two allotropic modifications whose abilities to dissolve a given solute differ considerably, the high-temperature phase transformed to martensite depends to a large extent upon the temperature attained in cooling, there being a rather distinct beginning temperature. (2) A metastable phase of steel, formed by a transformation of austenite below the Ms (or Ar) temperature. It is an interstitial supersaturated solid solution of carbon in iron having a body-centered tetragonal lattice.

Its microstructure is characterized by an acicular, or needle-like, pattern. A distinctive needle like structure existing in steel as a transition stage in the transformation of austenite. It is the hardest constituent of steel of eutectoid composition. It is produced by rapid cooling from quenching temperature and is the chief constituent of hardened carbon tool steels. Martensite is magnetic.

Martensite Range - The interval between the Ms and Mf temperatures.

Matalloid - (a) Element intermediate in luster and conductivity between the true metals and non-metals. Arsenic, antimony, boron, tellurium, and selenium, etc., are generally considered metalloids; frequently one allotropic modification of an element will be non-metallic, another metalloid in character. Obviously, no hard and fast line can be drawn. (b) In steel metallurgy, metalloid has a specialized, even if erroneous, meaning; it covers elements commonly present in simple steel; carbon, manganese, phosphorus, silicon and sulfur.

Matrix - The principal phase or aggregate in which another constituent is embedded.

Matt or Matte Finish - (Steel) Not as smooth as normal mill finish. Produce by etched or mechanically roughened finishing rolls.

Mechanical Polishing - A method of producing a specularly reflecting surface by use of abrasives.

Mechanical Properties - The properties of a material that reveal its elastic and inelastic behavior where force is applied, thereby indicating its suitability for mechanical application; for example, modulus of elasticity, tensile strength, elongation, hardness, and fatigue limit. These properties have often been designated as physical properties, but the term mechanical properties is much to be preferred. The mechanical properties of steel are dependent on its microstructure.

Mechanical Spring - Any spring produced by cold forming from any material with or without subsequent heat treatment.

Mechanical Twin - A twin formed in a metal during plastic deformation by simple shear of the structure.

Mechanical Working - Plastic deformation or other physical change to which metal is subjected, by rolling, hammering, drawing., etc. to change its shape, properties or structure.

Medium-Carbon Steel - Contains from 0.30% to 0.60% carbon and less than 1.00% manganese. May be made by any of the standard processes.

Melting Point - The temperature at which a pure metal, compound or eutectic changes form solid to liquid; the temperature at which the liquid and the solid are in equilibrium.

Melting Range - The range of temperature in which an alloy melt; that is the range between solidus and liquidus temperatures.

Metal - An opaque, lustrous, elemental substance that is a good conductor of heat and electricity and, when polished, a good reflector or light. Most metals are malleable and ductile and are, in general, denser than other substances.

Metal Spraying - A process for applying a coating of metal to an object. The metal, usually in the form of wire, is melted by an oxyhydrogen or oxyacetylene blast or by an electric arc and is applied at high speed by gas pressure against the object being coated.

Metallography - The science concerning the constituents and structure of metals and alloys as revealed by the microscope.

Metalloid - (a) Element intermediate in luster and conductivity between the true metals and nonmetals. Arsenic, antimony, boron, tellurium, and selenium, etc. are generally considered metalloids; frequently one allotropic modification of an element will be non-metallic, another metalloid in character. Obviously, no hard and fast line can be drawn. lb) In steel metallurgy, metalloid has a specialized, even if erroneous, meaning; it covers elements commonly present in simple steel; carbon manganese, phosphorus, silicon and sulfur.

Metalograph - An optical instrument designed for both visual observation and photomicrography of prepared surfaces of opaque materials at magnifications ranging from about 25 to about 1500 diameters.

Metastable - Possessing a state of pseudo-equilibrium that has a free energy higher than that of the true equilibrium state but from which a system does not change spontaneously.

Mf Temperature - The temperature at which martensitic transformation is essentially complete during cooling after austenitization.

Microbands (deformation) - Thin sheet like volumes of constant thickness in which cooperative slip occurs on a fone scale. They are an instability which carry exclusively the deformation at medium strains when normal homogeneous slip is precluded. The sheets are aligned at +/- 55(degrees) to the compression direction and are confined to individual grains, which usually contain two sets of bands. Compare shear bands.

Microcrack - A crack of microscopic size.

Micrograph - A graphic reproduction of the prepared surface of a specimen at a magnification greater than ten diameters. When photographed, the reproduction is known as a photomicrograph (not a microphotograph).

Microstructure - The structure of a prepared surface of a metal as revealed by a microscope at a magnification greater than ten diameters.

Mild Steel - Carbon steel containing a maximum of about 0.25% C.

Mill Edge - The edge of strip, sheet or plate in the as rolled state. Unsheared.

Mill Finish - A surface finish produced on sheet and plate. Characteristic of the ground finish used on the rolls in fabrication.

Modulus of Elasticity - A measure of the rigidity of metal. Ratio of stress, within proportional limit, to corresponding strain. Specifically, the modulus obtained in tension or compression is Young's modulus, stretch modulus or modulus of extensibility; the modulus obtained in torsion or shear is modulus of rigidity, shear modulus or modulus of torsion; the modulus covering the ratio of the mean normal stress to the change in volume per unit volume is the bulk modulus. The tangent modulus and secant modulus are not restricted within the proportional limit; the former is the slope of the stress-strain curve at a specified point; the latter is the slope of a line from the origin to a specified point on the stress-strain curve. Also called elastic modulus and coefficient of elasticity.

Modulus of Elasticity (tension) - Force which would be required to stretch a substance to double its normal length, on the assumption that it would remain perfectly elastic, i.e., obey Hooke's Law throughout the twist. The ratio of stress to strain within the perfectly elastic range.

Mold - A form of cavity into which molten metal is poured to produce a desired shape.

Molybdenum - Mo

Atomic Number: 42
Atomic Weight: 95.94
Melting Point: 2896 K (2623°C or 4753°F)
Boiling Point: 4912 K (4639°C or 8382°F)
Density: 10.2 grams per cubic centimeter
Phase at Room Temperature: Solid

Hard, tough metal of grayish-white color, becoming very ductile and malleable when properly treated at high temperatures. Pure molybdenum can best be obtained as a black powder, by reduction of molybdenum trioxide or ammonium molybdate with hydrogen. From this powder, ductile sheet and wire are made by powder metallurgy techniques; these are used in radio and related work. Its principal functions as an alloy in steel making: (1) Raises grain-coarsening temperature of austenite. (2) Deepens hardening. (3) Counteracts tendency toward temper brittleness. (4) Raises hot and creep strength, red hardness. (5) Enhances corrosion resistance in stainless steel. (6) Forms abrasion-resisting particles. It increases hardenability of steels and helps maintain a specified hardenability. It increases high temperature tensile and creep strengths. Molybdenum hardened steels require higher tempering temperatures for softening purposes.

Ms Temperature - The temperature at which a martensitic transformation starts during cooling after austenitization.

Muntz Metal (A refractory Alloy) - Alpha-beta brass, 60% copper and 40% zinc. Stronger than alpha-brass and used for castings and hot-worked (rolled, stamped, or extruded) products. High strength brasses are developed from this by adding other elements.

Music Wire - A polished high tensile strength cold drawn wire with higher tensile strength and higher torsional strength than any other material available. These high mechanical properties are obtained by a combination of the high carbon content, the patenting treatment and by many continuous passes through drawing dies. The high toughness characteristic of this material is obtained by the patenting. Such wire is purchased according to tensile strength, not hardness.

Natural Aging - Spontaneous aging of a supersaturated solid solution at room temperature.

NDT - Non-destructive testing. (Used mainly in the Pipe Mill.)

Necking - Local reduction of the cross-sectional area of metal by stretching.

Needle Cutter Steel - Usually supplied quarter hard rolled, extra precision rolled with sheared edges. Carbon content 1.25 - Chromium .15. Usually supplied in a 2 width from .002 to .035. Used for cutting the eyes of needle and milling the latch in a latch needle.

Network Structure - A structure in which the crystals of one constituent are surrounded by envelopes of another constituent which gives a network appearance to an etched test specimen.

Neumann Band - A mechanical (deformation) twin in ferrite.

Nickel – Ni

Atomic Number: 28
Atomic Weight: 58.6934
Melting Point: 1728 K (1455°C or 2651°F)
Boiling Point: 3186 K (2913°C or 5275°F)
Density: 8.912 grams per cubic centimeter
Phase at Room Temperature: Solid

Silvery white, slightly magnetic metal, of medium hardness and high degree of ductility and malleability and resistance to chemical and atmospheric corrosion. Used for electroplating. Used as an alloying agent, it is of great importance in iron-base alloys in stainless steels and in copper-base alloys such as Cupro-Nickel, as well as in nickel-base alloys such as Monel Metal. Its principal functions as an alloy in steel making: (1) Strengthens unquenched or annealed steels. (2) Toughens pearlitic-ferritic steels (especially at low temperature). (3) Renders high-chromium iron alloys austenitic. It is used in low alloy steels to reduce the sensitivity of the steel to variations in heat treatment and distortion and cracking on quenching. It also improves low temperature toughness and hardenability.

Nickel Silver - Copper base alloys that contain 10-45% Zn. and 5-30% Ni.

Nickel Steel - Steel containing nickel as an alloying element. Varying amounts are added to increase the strength in the normalized condition to enable hardening to be performed in oil or air instead of water.

Niobium – Nb (was known as Columbium - Cb)

Atomic Number: 41
Atomic Weight: 92.90638
Melting Point: 2750 K (2477°C or 4491°F)
Boiling Point: 5017 K (4744°C or 8571°F)
Density: 8.57 grams per cubic centimeter
Phase at Room Temperature: Solid

It is steel gray in color and brilliant luster. It is used mainly in the production of stabilized austenitic chromium-nickel steels, also to reduce the air-hardening characteristics in plain chromium steels of the corrosion resistant type. It lowers transition temperature and raises the strength of low carbon steel. Niobium increases strength at elevated temperatures, results in finer grain size and forms stable carbides, lowering the hardenability of the steel.

Nitriding - Process of surface hardening certain types of steel by heating in ammonia gas at about 935-1000 (degrees) F., the increase in hardness being the result of surface nitride formation. Certain alloying constituents, principal among them being aluminum, greatly facilitate the hardening reaction. In general, the depth of the case is less than with carburizing. Introducing nitrogen into a solid ferrous alloy by holding at a suitable temperature (below Ac1 for ferritic steels) in contact with a nitrogenous material, usually ammonia of molten cyanide of appropriate composition. Quenching is not required to produce a hard case.

Nitriding Steel - Steel which is particularly suited for the nitriding process, that is, it will form a very hard and adherent surface upon proper nitriding (heating in a partially dissociated atmosphere of ammonia gas). Composition usually .20-.40 carbon, .90-1.50 chromium, .15-1.00 molybdenum, and .85-1.20% aluminum.

Nitrogen - N

Atomic Number: 7
Atomic Weight: 14.0067
Melting Point: 63.15 K (-210.00°C or -346.00°F)
Boiling Point: 77.36 K (-195.79°C or -320.44°F)
Density: 0. 0012506 grams per cubic centimeter
Phase at Room Temperature: Gas

Increases the strength, hardness and machinability of steel, but it decreases the ductility and toughness. In aluminum killed steels, nitrogen combines with the aluminum to provide grain size control, thereby improving both toughness and strength. Nitrogen can reduce the effect of boron on the hardenability of steels.

Nodular Pearlite - Pearlite that has grown as a colony with an approximately spherical morphology.

Non-Ferrous Metals - Metals or alloys that are free of iron or comparatively so.