A process of case hardening an iron-base alloy by the simultaneous absorption of carbon and nitrogen by heating in a cyanide salt. Cyaniding is usually followed by quenching to produce a hard case.
Lets’ see what and how the heat treatment makes the goods better,
Decarburization: The loss of carbon from the surface of an iron-base alloy as the result of heating in a medium that reacts with the coal.
Drawing: Drawing, or drawing the temper, is synonymous with Tempering, which is preferable.
Eutectic Alloy: The alloy composition that freezes at a constant temperature similar to a pure metal. The lowest melting (or freezing) combination of two or more minerals. The alloy structure (homogeneous) of two or more solid phases formed from the liquid eutectic alloy.
Hardenability: In a ferrous alloy, the property that determines the depth and distribution of hardness induced by quenching.
Hardening: Any process of increasing hardness of a metal by suitable treatment, usually involving heating and cooling. Also: See Aging
Hardening, Case: A method of surface hardening involving a change in the composition of the outer layer of an iron-base alloy followed by appropriate thermal treatment. Typical case-hardening processes are Carburizing, Cyaniding, Carbonitriding, and Nitriding.
Hardening, Flame: A process of heat treatment Company in USA use the surface layer of an iron-base alloy above the transformation temperature range using a high-temperature flame, followed by quenching.
Hardening, Precipitation: A process of hardening an alloy in which a constituent precipitates from a robust supersaturated solution. See also Aging.
Hardening, Secondary: An increase in hardness following the normal softening that occurs during the tempering of certain alloy steels.
Heating, Differential: A heating process by which the temperature is made to vary throughout the object heated so that on cooling, different portions may have such different physical properties as may be desired.
Heating, Induction: A process of local heating by electrical induction.
Heat Treatment: A combination of heating and cooling operations applied to a metal or alloy in the solid state to obtain desired conditions or properties. Heating for the sole purpose of hot working excluded from the meaning of this definition.
Heat Treatment, Solution: A treatment in which an alloy is heated to a suitable temperature and held at this temperature for a sufficient length of time to allow the desired constituent to enter into robust solution, followed by rapid cooling to maintain the part in the answer. The material is then in a supersaturated, unstable state, and may subsequently exhibit Age Hardening.
Homogenizing: A high-temperature heat-treatment process intended to eliminate or to decrease chemical segregation by diffusion.
Isothermal Transformation: A change in phase at a constant temperature.
Malleablizing: A process of annealing white cast iron in which the combined carbon is wholly or in part transformed to graphitic or free carbon and, in some cases, part of the coal obliterated. See Temper Carbon.
Maraging: A precipitation hardening treatment applied to a particular group of iron-base alloys to precipitate one or more intermetallic compounds in a matrix of essentially carbon-free martensitic.
