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Alloy Steel a steel to which one or more alloying elements other than carbon have been deliberately added (I.e. chromium, nickel, molybdenum) to achieve a particular physical property.
Annealing the process of subjecting steel to high heat, with subsequent gradual cooling, to soften the steel thoroughly and render it less brittle.
B Chemical symbol for Boron
Be Chemical symbol for Beryllium
Bi Chemical symbol for Bismuth
Billet A section of steel used for rolling into bars, rods, and sections. It can be a product of the ingot route, or produced by continuous casting.
Bloom A large square section of steel intermediate in the rolling process between an ingot and a billet. Blooms are often produced by the continuous casting process eliminating the necessity of first producing an ingot.
C Chemical symbol for Carbon
Ca Chemical symbol for Calcium
Calcium In the form of calcium silicide acts as a deoxidizer and degasifier when added to steel. Both carbon and alloy steels modified with small amounts of calcium show improved machinability and longer tool life. Transverse ductility and toughness are also enhanced.
Carbon Carbon is an essential element in steel; it is added in specific amounts to control the hardness and strength of the material. In general, increased carbon content reduces ductility but increases tensile strength and the ability of the steel to harden when cooled rapidly from elevated temperatures.
Carbon Steel A steel whose properties are determined primarily by the amount of carbon present. Apart from iron and carbon, manganese up to 1.5% may be present as well as residual amounts of alloying elements such as nickel, chromium, molybdenum, etc. It is when one or more alloying elements are added in sufficient amount that it is classed as an alloy steel.
Carburizing is adding carbon to the surface of steel by heating the metal in contact with carbonaceous solid"s, liquids, or gases. The depth of the penetration of carbon into the surface is controlled by the time and temperature of the treatment. After carburizing it is necessary to harden the components by heating to a suitable temperature and quenching.
Case Hardening a process of surface hardening involving a change in the composition of the outer layer of an iron-base alloy by inward diffusion from a gas or liquid followed by appropriate thermal treatment. Typical hardening processes are carburizing, cyaniding, carbo-nitriding, and nitriding. Both carbon and alloy steels are suitable for case-hardening providing their carbon content is low, usually up to a maximum of 0.2%.
Cb Chemical symbol for Columbium
Ce Chemical symbol for Cerium
Charpy Test A test to measure the impact properties of steel.
Chromium When used as an alloying element, chromiumn increases the hardenability of steel an din association with high carbon gives resistance to wear and abrasion. Chromium has an important effect on corrosion resistance and is present in stainless steels in amounts of 12-20%.
Co Chemical symbol for Cobalt
Cobalt An alloying element used in tool, magnet and heat resisting steels. Together with tungsten and molybdenum, cobalt is used to form the super high speed steels.
Cold Finished a generic term used to designate three classes of cold processed bars: (1) cold drawn bars, (2) turned and polished shafting, and (3) ground and polished bars.
Cr Chemical symbol for Chromium
Critical Point This generally refers to a temperature at which some chemical or physical change takes place. The temperatures vary with the carbon content of the steel and the rate of cooling.
Cu Chemical symbol for Copper
Decarburization when steel is subjected to high temperatures, such as are used in hot rolling, forging, and heat treating, there is a loss of carbon at the surface which is known as decarburization. This is the reverse of carburization.
Descaling The process of removing the scale from hot rolled bars before cold finishing. It is normally carried out by shot blasting or pickling in acid.
Die When the term die is applied to steel, it often refers to the drawing dies through which hot rolled bars are drawn to produce the finish and dimensional accuracy that is required for cold finished steel.
Drawing The process of pulling metal wire, rods, or bars through a die with the effect of altering the size, finish, and mechanical properties. It is also a term used for tempering.
Ductility the property of a metal which allows it to be permanently deformed, in tension, before final rupture.
Elasticity The property which enables a material to return to its original shape and dimension.
Elongation the amount of permanent extension in the ruptured tensile-test specimen. It is usually expressed as a percentage of the original gage length.
Endurance Limit a limiting stress below which a metal will withstand a specified large number of applications of stress.
Etching Treatment of a prepared metal surface with acid or other chemical reagent which, by differential attack, reveals the structure.
F Chemical symbol for Flourine
Fatigue Limit The maximum value of the applied alternating stress which a test piece can stand indefinately.
Fatigue Strength the unit stress that ruptures a bar after an enormous (around 40 million) number of repetitions of a load covering a range of values.
Fe Chemical symbol for Iron
Ferrite A constituent of carbon steels. It is magnetic and soft.
Freecutting Steels Steels which have had additions made to improve machinability. The most common additives are sulphur and lead, while other elements used include tellurium, selenium, and bismuth.
Ga Chemical symbol for Gallium
Ge Chemical symbol for Germanium
Good Machinability the characteristics of a material that result in easy, fast machining, less downtime, less secondary finishing operations, improved tool life, and less overall cost of the machined part.
Grain Size Grain size is normally quantified by a numbering system. Coarse 1-5 and Fine 5-8. The number is derived from the formula N=2^(n-1) where n is the number of grains per square inch at a magnification of 100 diameters. Grain size has an important effect on physical properties. It is generally considered that fine grain steels have a better combination of strength and toughness, whereas coarse grain steel have better machinability.
Grinding A machining process to perform either of two effects: (1) to shape components that are too hard to be machined by conventional methods such as hardened tool steels and case hardened components, or (2) to obtain a high degree of dimensional accuracy and surface finish.
Guage Length Used in the mechanical testing of steel, it is the length marked on the parallel portion of a tensile test piece from which the elongation is measured.
H Chemical symbol for Hydrogen
Hardenability the ability of a steel to achieve a desired hardness under defined conditions of heating and cooling.
Hardening the formation of martensite resulting from the heating and quenching of certain iron-base alloys.
Hardness The hardness of steel is generally determined by testing its resistance to deformation. A number of methods are employed including Brinell, Vickers and Rockwell. For steel there is an empirical relationship between hardness and tensile strength and the hardness number is often used as a guide to the tensile strength.
Heat This term often defines the batch or cast produced from a single melting operation.
Heat Treatment one or more operations involving the heating and cooling of a metal or an alloy in the solid" state for the purpose of obtaining certain desirable conditions or properties.
Hydrogen An undesirable impurity if present in steel and can cause fine hairline cracks especially in alloy steels.
I Chemical symbol for Iodine
Impact Strength the energy absorbed by a specimen under a sudden blow of a certain intensity.
In Chemical symbol for Indium
Inclusions Usually non-metallic particles contained in metal. In steel they may consist of simple or complex oxides, sulphides, silicates and sometimes nitrides of iron, maganese, silicon, aluminium and other elements. In general they are detrimental to mechanical properties buy much depends on the number, their size, shape and distribution.
Iron The term iron refers to the chemical element iron or pure iron and is the chief constituent of all commercial iron and steel.
Jominy Test A method for determining the hardenability of steel.
K Chemical symbol for Potassium
Killed Steel Steel that has been completely deoxidized by the addition of an agent such as silicon or alumimium, before casting, so that there is practically no evolution of gas during solid"ification. Killed steels are characterized by a high degree of chemical homogeneity and freedom from porosity.
La Chemical symbol for Lanthanum
Lap A defect appearing as a seam on a rolled bar. Laps are rolled over pieces of material that arise when a bar is given a pass through the rolls after a sharp overfill or fin has been formed, causing a protrusion to be rolled into the surface of the product. The presence of oxides usually prevents the lap welding to the original bar surface, so that in subsequent cold finishing it is carried through as a longitudinal crack.
Lead When added to steel, lead does not go into solution but exists in a very finely divided state along the grain boundaries. It greatly assists machinability as it acts as a lubricant between steel and the tool face.
Li Chemical symbol for Lithium
Machinability Simply defined as a measure of the ease with which a metal can be machined satisfactorily.
Manganese One of the most important constituents of steel in which it fulfils a number of functions. It acts as a mild de-oxidizing agent. It combines with the sulphur present to form globular inclusions of Manganese Sulphide which are beneficial to machining. It increase tensile strength and hardenability of steel.
Martensite is the structure in quenched steel.
Mechanical Properties are those characteristics measured under certain conditions which reveal the reaction of a material to an applied force.
Mg Chemical symbol for Magnesium
Mn Chemical symbol for Manganese
Mo Chemical symbol for Molybdenum
Molybdenum Its use as an alloying element in steel increase hardenability and in low alloy steels reduces the risk of temper brittleness. It is used in stainless steels as well as high speed steels.
N Chemical symbol for Nitrogen
Na Chemical symbol for Sodium
Nb Chemical symbol for Niobium
Ni Chemical symbol for Nickel
Nickel One of the most widely used alloying elements in steel. In amounts of 0.50% to 5.00% its use in alloy steels increases the toughness and tensile strength without detrimental effect on the ductility. Nickel also increases the hardenability.
Niobium Also known as columbium. Niobium is a strong carbide forming element.
Nitrogen Nitrogen is a gas that forms approximately 70% by volume and 77% by weight of the atmosphere. It can combine with many metals to form nitrides and is thus applied to the case hardening of steel.
Normalizing heating steels to approximately 100 degrees Farenheit above the critical temperature range followed by cooling to below that range in still air at ordinary temperature.
O Chemical symbol for Oxygen
Occlusion A term applied, in the case of metals, to the absorption or entrapment of gases.
Os Chemical symbol for Osmium
Oxidation A common form of chemical reaction which is the combining of oxygen with various elements and compounds. The corrosion of metals is a form of oxidation.
P Chemical symbol for Phosphorus
Pd Chemical symbol for Palladium
Pearlite is the structure of annealed or soft steel.
Ph Chemical symbol for Lead
Phosphorus The presence of this element in steel is usually regarded as an undesirable impurity due to its embrittling effect. In most steels it is limited to a maximum of 0.050%.
Quenching the process of cooling steel suddenly by immersion, usually in water or oil.
Ra Chemical symbol for Radium
Rb Chemical symbol for Rubidium
Re Chemical symbol for Rhenium
Reduction of Area the diminution in section per unit of original area as applied to a bar that has been subjected to tensile forces and ruptured.
Rh Chemical symbol for Rhodium
Rockwell Hardness A method for determining the hardness of metals by determining the depth of penetration of a steel ball.
Rolling The process of shaping metals by passing it between rolls revolving at the same peripheral speed and in opposite directions.
Ru Chemical symbol for Ruthenium
S Chemical symbol for Sulphur
Sb Chemical symbol for Antimony
Scale The oxidized surface of steel produced during hot working, such as rolling, and by exposure to air or steam at elevated temperatures.
Se Chemical symbol for Selenium
Seam A surface defect formed from blow holes in the ingot, non metallic inclusions, or stresses arising during the solid"ification stage. They appear as longitudinal discontinuities in the bar.
Selenium An element that closely resembles sulphur in its properties. The main use in steel is as a freecutting additive buy due to high cost its use is limited primarily to stainless steel.
Steel Generally defined as a metallic product whose principal element is iron and where the carbon content is not more than 2%.
Stress Relieving a thermal process for reducing internal stresses in metals.
Sulphur Generally regarded as an impurity in steel as it can have detrimental effects on strength, ductility, and weldability as well as producing hot and cold shortness. Its content in most steels is limited to a maximum of 0.050%. Sulphur is beneficial to machining and is added to freecutting steels in amounts up to 0.35% with the manganese content increased to overcome any detrimental effects.
Ta Chemical symbol for Tantalum
Tantalum A rare metal of silver white color having excellent corrosion resistance and high melting point. It is widely used for chemical process equipment and specialized aero-space and nuclear applications.
Te Chemical symbol for Tellurium
Tellurium Its primary use in steel is as an additive in leadbearing freecutting steels to further improve their machinability.
Tempering reheating a hardened steel to a specified temperature followed by any desired rate of cooling for the purpose of relieving stresses set up by quenching and to develop toughness and ductility.
Tensile Strength the maximum load per unit of original cross sectional area sustained by a material during the tension test.
Tension Test a test in which a specimen is broken by applying an increasing load to the two ends. During the test the elastic properties and the ultimate tensile strength of the material are determined. After rupture, the broken specimen may be measured for elongation and reduction of area.
Ti Chemical symbol for Titanium
Tin When present in steel it is an undesirable impurity which gives rise to temper brittleness. When used as a coating, it has good resistance to corrosion for many applications.
Titanium Small amounts added to steel contribute to its soundness and give a finer grain size.
Tool Steel A generic term applied to a wide range of steels, both carbon and alloy, which are suitable for various types of cutting tools, press tools, dies, etc.
Toughness The ability of a material to withstand shock loading. It is the exact opposite of brittleness which carries the implication of sudden failure.
Tungsten When used as an alloying element, it increases the strength of steel at normal and elevated temperatures.
U Chemical symbol for Uranium
Ultrasonic Inspection A means of locating defects in steel. When acoustic energy in the ultrasonic range is passed through steel, the sound waves tend to travel in straight lines. If there is a defect in the path of the beam it will cause a reflection of some energy depleting the energy transmitted. The resulting acoustic shadow can allow for the detection of these defects.
V Chemical symbol for Vanadium
Vacuum Degassing A ladle of molten steel is placed within a chamber which is then evacuated. This reduces the gas content, particularly hydrogen, as well as reducing non-metallic inclusions.
Vanadium Steels with vanadium have a much finer grain structure.
W Chemical symbol for Tungsten
Yield Point the stress at which a piece under strain yields markedly, becoming permanently distorted without increase of load.
Zinc A metallic chemical element used as a protective coating for iron and steel sheet and wire.
Zirconium Acts as a deoxidizing element in steel and combines with sulphur.
Zn Chemical symbol for Zinc
Zr Chemical symbol for Zirconium