| Glossary of Technical Terms |
A ACID BRITTLENESS-Commonly attributed to the absorption of hydrogen, this is the brittleness induced in steel when itis pickled in a diluted solution of acid for the purpose of removing scale, or upon lectroplating. ACID LINING-The inner bottom and lining of a melting furnace composed of materials having an acid reaction (sand, siliceous rock, or silica bricks). ACID STEEL-Steel melted in a furnace having an acid bottom and lining and under a slag with acid reaction. The term has no reference to the acidity of the steel. AGING-The spontaneous change in the properties of a metal usually associated with the recovery of the metal from an unstable condition produced by quenching (quench-aging) or by cold working (strain-aging). Age hardening and aging are terms commonly used synonymously. See also "Precipitation Hardening." AIR HARDENING (Air Quenching)-A hardening process wherein the steel is heated to the hardening temperature and cooled in air. Unless steel is high in carbon or alloy, or both, it will not show much increase in ardness when air hardened. ALLOY-A mixture with metallic properties composed of two or more elements of which at least one is a metal. AMORRPHOUS -Non-crystalline. ANNEALING-Annealing generally refers to the heating and retarded cooling of solid material for the purpose of removing stresses, making it softer, refining its structure or changing its ductility, toughness of other properties. Specific heat treatments covered by the term annealing include black annealing blue annealing, box annealing, bright annealing, full annealing, graphitizing, malleablizing and process annealing. ASROLLED- When bars are hot rolled and allowed to cool in the air, they are said to be in the "as rolled" or natural condition. AUSTEMPERING-A patented heat treating process that consists of quenching an iron-base alloy from a temperature above the transformation range in a medium having a high rate of heat abstraction, and then maintaining the metal, until transformation is complete, at a substantially uniform temperature which is below that of pearlite formation and above that of martensite formation. AUSTENITIC STEELS-Added to steel in large amounts, several alloying elements such as nickel and chromium have the effect of lowering the transformation temperatures below ordinary air temperatures. As a result of the lowering of the transformation, the structure at ordinary room temperatures is austenite; therefore, these steels are known as austenitic steels. B BANDED STRUCTURE- A characteristic microstructure consisting of parallel bands of ferrite and pearlite which run in the direction of working. BARK -Decarburized skin found just beneath the scale. BASIC BOTTOM OR LINING-The inner lining and bottom of a melting furnace composed of materials having a basic reaction; these may be crushed burnt dolomite, magnesite, magnesite bricks or basic slag. BASIC STEEL-Steel melted in a furnace with a basic bottom and lining and under a slag having a basic reaction. Most steel made in America is basic. BEND TEST-A test commonly made by bending a cold sample of specified size through a specified circular angle. Bend tests provide an indication of the ductility of the sample. BESSEMER PROCESS-A steel-making process in which air is blown through the molten pig iron in removing impurities by oxidation. BILLET-A semi-finished rolled ingot of rectangular cross section or nearly so. In general the term "billet" is used when the cross section ranges from 4 up to 36 sq. in., the width always being less than twice the thickness. Small sizes are usually classed as bars or "small billets." The term "bloom" is properly used when the cross section is greater than about 36 sq. in., though this distinction is not universally observed. BILLET MILL -See "Blooming Mill." BLACK ANNEALING-A process of box annealing of sheets prior to tinning whereby a black oxide color is imparted to the surface of the product. BLAST FURNACE-A shaft furnace supplied with air blast, usually hot, for producing pig iron by smelting iron ore. The furnace is continuous in operation, the raw materials (iron ore, coke, and limestone) are charged at the top, and the molten pig iron and slag are collected at the bottom and are tapped out at intervals. BLISTER -A defect in metal produced by gas bubbles either on thesurface or formed beneath the surfce while the metal is hot orplastic. Very fine blisters are called pinhead or pepperblisters. BLOOM -See "Billet." BLOOMING MILL -A mill used to reduce ingots to blooms, slabs, etc. BLOWHOLE-A hole produced during the solidification of metal by evolved gas which, in failing to escape, is held in the metal. BLUE ANNEALING-A process of annealing sheets after rolling The sheets, if fairly heavy, are allowed to cool slowly after the hot rolling; if of lighter gauge, as is usually the case, they are passed singly through an open furnace for heating to the proper annealing temperature As the name indicates, the sheets have a bluish-black appearance. BLUEING-A method of coating sheets with a thin, even film of bluish black oxide. The blued surface is obtained by exposure to an atmosphere of dry steam or air at a temperature of about 1000°F. Generally this is done during box annealing. BOX ANNEALING-Softening steel by heating, usually at a subcritical temperature, in a suitable closed metal box or pot to protect it from oxidation, employing a slow heating and cooling cycle; also called close annealing or pot annealing. BRIGHT ANNEALING-An annealing process usually carried out in a controlled furnace atmosphere so that surface oxidation is reducedto a minimum and the surface remains relatively bright. BRINELL HARDNESS TEST-This test consists of forcing a ball of standard diameter into the specimen being tested under standard pressure, and judging the hardness of the material by the amount of metal displaced. BURNING-Heating steel to a temperature sufficiently close to the melting point to expose it to the danger of "burning." Such may be caused by the melting of the more fusible const, by the penetration of gases such as oxygen into the metal with consequent reactions, or perhaps by the segregation of elements already present in the metal. C CALORIZING-A process of converting the surface of steel articles into a corrosion-resistant alloy layer of aluminum and iron. (See Cementation.) CARBIDES-As found in steel,carbides are compounds of carbon and one or more of the metallic elements, such as iron, chromium, tungsten, etc. CARBON FREE -Metals and alloys which are practically free from carbon. CARBO-NITRIDING-A process of case hardening an iron-base alloy by the simultaneous absorption of carbon and nitrogen through heat' in a gaseous atmosphere of suitable composition, followed by either quenching or cooling slowly, as required. CARBON RANGE-In steel specifications, the carbon range is the difference between the minimum and maximum amount of carbon acceptable. CARBON STEEL-Steel whose major properties depend on its carbon content and ' which other alloying elements are negligible. CARBURIZING-Adding carbon to iron base alloys by absorption through heating the metal at a temperature below its melting point ' contact with carbonaceous materials. The oldest method of case hardening. (See Cementation.) CARBURIZING COMPOUND-Mixtures containing carbonaceous solids which will give up carbon to steel in the presence of heat. Gas rich in carbon is sometimes used in the carburizing process. CASE-The surface layer of an iron-base alloy which has been made substantially harder than the interior by the process of case hardening. CASE HARDENING-Carburizing and subsequent hardening, by heat treatment of surface areas whose carbon content has been increased by carburizing. CAST STEEL -Any object made by bouring molten steel into molds. CASTING STRAINS-Strains produced by internal stresses set up by non-uniform cooling. CEMENTATION-This process consists of converting the surface of a metal into an alloy layer by heating it while surrounded by another metal or non-metal which is generally in a powdered form. Carburizing, sherardizing, calorizing, chromizing, and nitriding are included among the cementation processes. CHARPY TEST-A test made to determine the notched toughness, or impact strength, of a material. The test gives the energy required to break a standard notched specimen supported at the two ends. CHEMICAL ANALYSIS-Qualitative analysis consists of separating a substance into its component elements and identifying them. In quantitative analysis the proportion of all component elements are determined. CHILL CAST PIG-Pig iron cast into metal molds or chills. If a machine is used the product is known as machine cast pig. CHIPPING-One method of removing surface defects such as small fissures or seams from partially worked metal. If not eliminated, the defects might carry through to the finished materials. If the defects are removed by means of a gas torch the term "deseaming" or "scarfing" is used. CHROMIUM-A hard, grayish white and corrosion resistant metal widely used as an alloying element in steel and for plating steel products. CLEAVAGE PLANE-Crystals possess the property of breaking more readily in one or more directions than in others. The planes of easy rupture are called cleavage planes. COLD DRAWING -See "Cold Finishing." COLD FINISHING-Changing the shape of, or reducing the cross section of steel while cold-usually accomplished by rolling, drawing through a die or turning. COLD ROLLING -See "Cold Finishing." COLD SHUT-An area in metal where two portions of the metal in either a molten or plastic condition have come together but have failed to unite into an integral mass. COLD WORKING-Permanent deformation of a metal below its recrystallization temperature, which hardens the metal. COMBINED CARBON-All of the carbon in iron or steel which is combined with iron or other elements to form carbide. CORE-The center portion of a piece of steel which may be of different chemical composition than the outside as in the case of carburized parts, or which may have different physical properties than the outside due to the failure of penetration of heat treatment effect. CREEP STRENGTH-The maximum stress which can be applied to steel at a specified temperature without causing more than a specified percentage increase in length in a specified time. CRITICAL POINTS-The various temperatures at which transformations occur in steel as it passes through its critical range-on either a rising or falling temperature. (See Transformation Range.) CRITICAL RANGE-A temperature range in passing through which steel undergoes transformation. The preferred term is transformation range (q. v.). CRITICAL TEMPERATURES -See "Critical Points." CROP-The imperfect ends of a rolled or forged product which are removed and discarded. CUP FRACTURE-A type of fracture-which looks like a cup having the exterior portion extended with the interior slightly depressed-produced in a tensile test specimen. Usually an indication of ductility. CYANIDING-Surface hardening of an iron-base alloy article or portion of it by heating at suitable temperatures in contact with molten cyanide salt and then quenching. D DECALESCENCE-The absorption of heat, due to internal changes, which occurs when steel is heated through the critical temperature range. DEOXIDIZER-A substance added to molten steel for the purpose of removing oxygen. DEPTH OF PENETRATION-The depth to which appreciable hardening occurs when steel is quenched from its hardening temperature. DIFFERENTIAL HEATING-Heating so that various portions of an article reach different temperatures to produce different properties upon cooling. DISCARD -See "Crop." DISTORTION -A change in shape (usually refers to changes of shapecaused by internal stress). DRAWING -Drawing may refer to the pulling of steel through a die,as in drawing wire, or deforming steel in dies on a press (deepdrawing). DRAWING BACK-Reheating after hardening to a temperature below the critical for the purpose of changing the hardness of the steel. DUCTILITY-The ability to permit change of shape without fracture. In steel, ductility is usually measured by elongation and reduction of area as determined in a tensile test. E ELASTIC LIMIT-The maximum load per unit of area (usually stated as pounds per square inch) that may be applied without producing permanent deformation. It is common practice to apply the load at a constant rate of increase and also measure the increase of length of the specimen at uniform load increments. The point at which the increase in length of the specimen ceases to bear a constant ratio to the increase in load, is called the proportional limit. The elastic limit will usually be qualto or slightly higher than the proportional limit. ELONGATION-The increase in length of a test specimen after rupture in a tensile test, expressed as a percentage of the original length. ENDURANCE LIMIT -Maximum dynamic stress to which material may be submitted for an indefinite number of times without causing fatigue failure. ERICHSEN VALUES-These are widely used is conjuction with other measures as an indication of the deep drawing properties of steel sheets and strip. They are determined in a cupping test in which a conical punch with a round end is advanced into a test specimen held by a blank-holder until the test specimen fractures. The depth of the cup is measured in millimeters on a scale and becomes the Erichen value. EUTECTOID STEEL-Carbon steel with a 100 % pearlitic structure, which is the structure normal conditions of hot working and cooling when the proportion of carbon is about .80 per cent. Hyper-eutectoid steel has a greater percentage of carbon, and hypo-eutectoid steel has less carbon. F FATIGUE-See comments under spring steel and endurance strength of steels. FATIGUE LIMIT -See "Endurance Limit." FERRO ALLOYS-Iron alloyed with some element manganese, chrome, or silicon, etc., used in adding the element to molten steel. FIBER-A characteristic of wrought metal manifested by a fibrous or woody appearance of fractures and indicating directional properties. Fiber is due chiefly to the direction of working of the constituents of the metal both, metallic and non-metallic. FIBER STRESS-Unit stress at a certain point when on section stress is not uniform. FIN -Protuberances resulting from the improper squeezing of steel during rolling. Also see "Flash." FINISHED STEEL-Steel which is ready for the market with any further work or treatment such as wire, bars, sheets rails, plates, etc.. Blooms, billets, slabs, and wire rods semi-nished. FINISHING TEMPERATURE-Temperature at which hot working is completed. FLAKES-Crystalline areas of a steel fracture with a bright scaly appearance. FLAME ANNEALING-The direct application of a high temperature flame to a steel surface for the purpose of removing stresses and softening the metal. Commonly used to remove the stresses from welds. FLAME HARDENING-In this method of hardening, the surface layers of a medium or high carbon steel is heated by a high temperature torch and then quenched. FLASH-A thin fin of metal formed at the sides of a die forging or sometimes a rolledbar where a small portion of the metal is forced out between the edges of the forging dies or the rolls. FLASH POINT - Ingnition point-usually applied to oils. FORGING-A piece of metal which has been shaped or formed, while hot by forging with a hammer (hand or power), in a press, or by a drop hammer. FORGING STRESSES -Stresses resulting from forging or from coolingfrom the forging temperature. FRACTURE- The surface of a break in metal. FRACTURE TEST-Breaking metal to determine structure or physical condition by examining the fracture. FREE MACHINING-A term used to describe a metal which may be machined at relatively high speed without the development of excessive heat and from which the chips will break off easily leaving a smooth surface. FULL ANNEALING-Heating to above the critical temperature range followed by slow cooling through the range , producing maximum softness. FULL HARDNESS -Ususally the hardness of heat treated steel afterquenching and before tempering. G GRAIN GROWTH -The increase in the size of grains making up the microstructure of steel such as may occur during heat treatmens. GRAIN REFINEMENET -Reducing the crystalline structure as observedby eye or under the microscope. GRAPHITIZING -Annealing grey cast iron so that most of the carbonis transformed to the graphitic condition. COntrolled by increasingsilicon and by thermal treatment. H HAIR LINE SEAM -See "Seam." HARDENABILITY-(Of Steel)The ability of a steel to harden when cooled from its hardening temperature, as measured below the surface. HARDENING-(As applied to heat treatment of steel.) Heating and quenching to produce increased hardness. HEAT OD STEEL-The steel produced from one charge in the furnace, and consewuently practically identical in its characteristics. HEAT RESISTING STEEL-Those steels which are used for service at relatively high temperatures because they retain much of their strength and resist oxidation under such condition. HEAT TINTING-Heating a polished specimen in air for the purpose of obtaining an oxidized properties. HIGH DRAW-A drawing temperature not very much below the Ac1 point of the steel-used to develop high ductility wheen tempering steel after the quench. HOT SHORTNESS -Britleness in metal-at an elevated temperature. HOT TOP -sEE "Sinkhead." HOT WORKING-The mechanical working of metal above the recrystillization temperature. I IMPACT VALUES-Resistance to shock and ability to distribute localized stress as measured by impact test-usually expressed in foot pounds. INCLUSIONS-Particles of slag, dirt or ohter non-metallic substances in molten metal that are retained during solidification. INGOT-A casting intended for subsequent rolling or forging. Usually case in metallic molds. IZOD TEST-A test made to determinee the notched toughness of a material. The test gives the enegy required to break a standard notched specimen supported as a cantilever. J JOMININ END-QUENCH TEST(Cont.)-method which provides a very rapid rate of cooling all the way up to the other end. K KILLED STEEL-Steel to which sufficient deoxidizing agents have been added to prevent gas evolution during solidification. LAP-A surface defect appearing as a seam caused from folding over hot metal, fins, or sharp corners and then rolling or forging, without welding them into the surface. L LUTE-A fireclay mixture for sealling cracks to make a gas tight joint on annealing box covers, crucible coverss, etc. M MACHINABILITY-The ease of metal removal during machining, the tool life obtained, the surface finish obtained or any combination of these three. MACHINE STRAIGHTENING-Straightening metal bars by rolling in a straightening machine. MALLEABILIZING-An annealing operation performed on white cast iron for the purpose of partially or wholly transforming the combined carbon to temper carbon, and in some cases to remove completely the carbon from the iron by decarburization. MARTENSITE-With most steels, cooling as rapidly as possible from their quenching temperature develops a distinctive tructure called martensite. In this form, the steel is at its maximum hardness. MATRIX-The ground mass or principal substance in which a constituent is embedded. MECHANICAL WORKING-Working metal through rolls, presses, hammers, etc., to change its shape, properties or structures. MICROSCOPIC-Extremely small-not large enough to be seen with the naked eye. MICROSTRUCTURE-The structure of metals as revealed by examination of polished and etched samples with the microscope. MISCIBLE -Capable of being mixed. MODULUS OF ELASTICITY-The ratio, within the limit of elasticity, of the stress to the corresponding strain. The stress in pounds per square inch is divided by the elongation in inches for each inch of the original gauge length of the specimen. N NETWORK STRUCTURE-A structure in which the crystals of one constituent are partially or entirely surrounded by envelopes of another constituent, an arrangement that gives a network appearance to a polished and etched specimen. NICKEL STEEL-Alloy steel containing nickel as its principal alloying element. NITRIDING-Adding nitrogen to the solid iron-base alloys by heating at a temperature below the critical in contact with ammonia or some other nitrogeneous material. NORMALIZING-Heating to about 100°F. above the critical temperature and cooling to room temperature in still air. rovision is often made in normalizing for controlled cooling at a slower rate, but when the cooling is prolonged the term used is annealing. O OIL QUENCH-A quench from the hardening temperature, in which oil is the cooling medium. OLSEN TEST-This is a cupping test made on an Olsen machine as an aid in determining ductility and deep drawing properties. The test simulates a deep drawing operation. I: is continued until the cup formed from the steel sample fractures. Ductility and drawing properties are judged by the depth of the cup, position of the break, condition of the sur- the break, etc. OVERHEATING-Heating to such a temperature that while the properties of the metal are impaired, it has not been burned and can therefore be restored by heat treatment. P PASSIVATION-Generally refers to a process for the surface treatment of stainless steels. Material is subjected to the action of an oxidizing solution, usually nitric acid, which augments and strengthens the normal protective oxide film enabling the material to resist corrosive attack. The passivating process also removes foreign substances from the surface which might cause local corrosion. PATENTING-Heating iron-base alloys above the critical temperature range followed by cooling below that range in air, or in molten lead or a molten mixture of nitrates or nitrites maintained at a temperature usually between 800-1050°F., depending on the carbon content of the steel and the properties required of the finished product. PEARLITE-A relatively hard constituent of steel made up of alternate layers of ferrite (iron), and cementite (iron carbide; that is, a compound of iron and carbon). See "Eutectoid Steel" PERMANENT MOLD-A metal mold which is used repeatedly for the production of many castings of the same form. PERMANENT SET -Permanent change in shape due to applicationof stress. PHOSPHOROUS BANDING-A visible band occurring in metals caused by localized phosphide segregations. PICKLING-Immersion of steel in a dilute solution of acid for the purpose of removing the scale. PIERCING-Producing a hole in hot metal by forcing a pointed tool through it. Frequently used in making steel tubes from solid steel bars. PIG IRON-So called whether cast in metal molds to form pigs or kept molten awaiting transfer to the steelmaking furnaces. The term, "hot metal," is also applied to molten pig iron. PIPE-cavity formed in metal (especially ingots) during the solidification of the last portion of liquid metal Contraction of the metal causes this cavity or pipe. PIT-A depression in the surface of metal occurring during its manufacture POT ANNEALING -See "Box Annealing." PRECIPITATION HARDENING-The process of hardening an alloy by heating it for the purpose of allowing a structural constituent to precipitate from a solid solution. PREHEATING-As a general term, preheating means a heating applied preliminary to some further thermal or mechanical treatment It also has a specific meaning in describing the process by which tool steel is heated slowly and uniformly to a temperature below the hardening temperature following which the steel is transferred to a furnace in whioh the temperature is substantially above the preheating temperature. PROCESS ANNEALING-Heating to a temperature below or close to the lower limit of the critical temperature range and then cooling as desired. PROPORTIONAL LIMIT-Stress at which the deformation ceases to be proportional to the load as determined by straino-meter (also, by a extensometer for tension, compressometer for compression and deflectometer for transverse tests, value being read from plotted results). See "Elastic Limit." Q QUENCHING -Cooling rapidly by immersion in oil, water, etc. QUENCHING MEDIUM-The medium used for cooling steel during heat treatment-usually oil, water, air, or salts. QUENCHING TEMPERATURE-The temperature from which steel is quenched during a heat treating process. R RECALESCENCE-The liberation of heat due to internal changes, which occurs when steel is cooled through the critical tetriperature range. RED SHORTNESS -See "Hot Shortness." REDUCTION OF AREA-The difference between the original cross-sectional area of a tensile specimen and that of the small-est area at the point of rupture. It is usually stated as a per-centage of the original area; also called "contraction of area." REFINEMENT OF STRUCTURE -See & quot;Grain Refinement." REFINING TEMPERATURE-A temperature employed in heat treatment to refine structure, in particular, to refine the grain size. Usually just above Ac3 in steel. REGENERATIVE QUENCHING-Quenching carburized parts from two differnet temperatures to refine case and core. (often called couble quenching.) RIMEED STEEL-A steel that is poured containing enough oxygen to evolve appreciable gas during solidification. The gas evolution results in a finished product having a very pure surface with the impurities concentrated in the interior. The pure zone which is readily shown by etching is reffered to as the "rim". ROCKWELL HARDNESS TEST-Forcing a cone-shaped diamond or hardened steel ball into the specimen being tested under standard pressure. The depth of penetration is an indication of the Rockwll Hardness. ROLLER LEVELER-A rolling device used for eliminating buckles and waves in steel sheets and strip and for producing sheets of commercial flatness. The roller leveler has sets of rolls that are staggered to flex the sheet as it pasess between them. Besides its use in leveling, it has extensive application for minimizing or temporarily eliminating the tendency to develop stretcher strains. S SCAB-A defect on the ingot caused by metal which splashes during teeming; on rolled or forged products it appears as a silver-like defect partially welded or mechanically bound to the parent metal surface. SCLEROSCOPE or SHORE HARDNESS TEST-This test consists of ropping a small diamond tipped hammer rebounds is a measure of the surface hardness of the specimen. SEAM-An elongated discontinuity in metal caused by blow hole or other defect which has been closed by rolling or forging mechanicaly but not welded. SECONDARY HARDENING-An increase in hardnessfollowinging the normal softening during the tempering of certain alloy steels. SELF-HARDENING STEEL-An alloy tool steel that hard when cooled in air and which will hold a cutting edge at temperatures nearing a dark red. SEMI-FINISHED -See `Finished Steel.' SHERARDIZING-A cementation process used to give steel articles, such as bolts, a corrosion resistant surface zinc-rich alloy. The articles are packed with zinc dust in drums which are heated for several hours while slowly rotating. SHORTNESS -Brittleness. SILKY FRACTURE-A steel fracture having a very smooth, fine grain, or silky appearance. SINKHEAD-A heat-insulated reservoir for excess molten metal, placed at the top of an ingot mold in order to feed molten metal into the shrinkage in the top of the ingot proper. SKELP -Steel or iron plate from which pipe or tubing is made. SLAB-A very thick rectangular piece of steel for rolling down into plates. SLABBING MILL -A mill for rolling slabs from ingots. SLIP BANDS-A series of parallel lines running across a crystalline grain. Slip bands are formed when the elastic limit is passed by one layer or portion of the crystal slipping over another portion along a plane, known as the slip plane. SLIP PLANE -See "Slip Bands." SOAKING-Holding steel at a predetermined temperature for a sufficient time to assure heat penetration and/or to complete the solution of carbides. SOLIDIFICATION RANGE -The temperature range through whichmetal freezes or solidifies. SOLID SOLUTION-A condition wherein one element is dissolved in another element while the dissolving element is in a solid and not liquid condition. SONIMS -Solid non-metallic inclusions in metal SPALLIN -G-Cracking and flaking of a metal surface. SPHEROIDIZING-Any of a number of processes of heating and cooling which cause the carbides to assume a spherical-like shape Ordinary steels are commonly spheroidized by prolonged heating at a temperature just below the lower limit of the transformation range with subsequent slow cooling. SPIEGEL (OR SPIEGELEISEN)-A pig iron containing 15 to 30% manganese and 4.5 to 5.5% carbon. STATIC LOAD-A load which is sustained without motion such a weight hanging on a string. STEP DOWN TEST-In this test, a sample of steel is machined down to a series of different diameters so that inspection can be made at different distances from the surface. STRESS -The load per unit area tending to deform a material. STRETCHER LEVELING-A method of producing unusual flatness in steel sheets by stretching them in a hydraulic device. STRECHER STRAINS-These are vein-like surface defects appear in low carbon steel during cold deformation. They are associated with the irregular movement of the metal when it is being strained at the yield point. Stretcher strains are also known as "Luder's lines," "strain figures," etc' STRUCTURAL GRAIN SIZE -See "Grain Structure." T TAPPING -Removing molten metalfrom a furnace. TEEMING -Pouring steel from the ladle to the molds. TEMPER CARBON-A form of graphite in iron-base alloys produced by heating below the melting point. TEMPERING-Reheating after hardening to a temperature range vital and then cooling. TENSILE STRENGTH-The maximum load per unit cross-sectional area obtained before rupture of s tensile specimen. TRANSFORMATION RANGE-The temperature range in which varios changes occur in the structure of steel and above necessary to heat steel to effect complete structural change. Normally, distinction should be made betwen the transformation range when heating and the range when cooling. W WATER QUENCH-(In steel heat treatment.) Cooling steel from its quenching temperature with water. WORK HARDNESS-Hardness resulting from mechanical working. XYZ YIELD POINT-The load per unit of original cross-section area at which a marked increase in the deformation of the specimen occurs without increase in load. Usually calulated from the load detemined by the drop of he beam of the testing machine or by use of dividers. The terms in this glossary have been carefully selected from the Steel Exchangeof Terms one can encounter in the shipping business. We hope you will find it useful. |