Heat Treatment Process

Heat Treatment Process Conducted by Hi-Tech are listed below.

Hardening: Increasing the hardness of the steels by quenching from the temperature within or above transformation range.

Tempering: A process of re-heating quench -hardened normalised steels to a temperature below the transformation range and cooling at any desired rate. Usually applied for the processes of producing a desired combination of mechanical properties.

Air Hardening: Hardening steels by air cooling from a temperature above the critical range.

Annealing: Heating and holding at a suitable temperature and then cooling at a suitable rate, for such purposes as reducing hardness, improving machinability, facilitating cold working, producing a desired microstructure and obtaining desired physical mechanical or other properties.

Austempering: Quenching from a temperature above the transformation range to some temperature above the upper limit of marten site formation, and holding at this temperature until the austenite is completely transformed for the purposes of conferring certain mechanical properties.

Carburizing: A process that introduces a carbon into a solid ferrous alloy by heating the metal in contact with a carbonaceous material in solid, liquid or gaseous form . The process is generally followed by quenching to produce a hardened case.

Case Hardening: Hardening a ferrous alloy so that the outer portion or case is made substantially harder than the inner portion or core. The term is usually applied to the Carburizing or nitriding treatments followed by quenching to produce a hard case and core suitable properties. Flame and induction hardening are not included in this definition.

Flame Hardening: Rapid heating of surface by means of flame to a temperature within or above the transformation range followed immediately by quenching.

Induction Hardening: Quench hardening in which heat is generated by electrical induction.

Full Annealing: Heating and holding at some temperature above the transformation range followed by cooling slowly through the transformation range.

Nitriding: Introducing nitrogen into a ferrous alloy by holding a suitable temperature in contact with a nitrogenous material usually ammonia or molten cyanide of appropriate composition (gas nitriding or Bath nitriding ).Quenching is not required to produce a hard case.

Quenching: Rapid cooling from elevated temperatures. It is carried out by contact with liquids or gases. Term also applied to the rapid cooling of austenitic steels from very high temperatures to obtain the most homogeneous possible austenite structure.

Mar Tempering: Quenching from the temperature above the transformation range to some temperature slightly above the upper limit of martensite formation, holding at that temperature long enough to permit equalization of temperature without transformation of the austenite, followed by cooling in air. This results in formation of martensite which may be tempered as desired.

Solution Treatment: Heating an alloy to a suitable temperature, holding at that temperature long enough to allow one or more constituents to enter into solid solution, & then cooling rapidly enough to hold the constituents in solution.

Stabilizing Treatment: Any treatment intended to stabilize the structure of an alloy or the dimensions of a part.

Spherodizing: (Spherodize Annealing) Subjecting steel to a selected temperature cycle usually within or near the transformation range in order to produce a suitable form of giobular carbide for such purposes as : Improving machinability, Facilitating subsequent cold working. Obtaining a desired structure for subsequent heat treatment.

Stress Relieving: Heating to a suitable temperature, holding long enough to reduce residual stresses & then cooling slowly enough to minimize the development of new residual stresses. The stresses relieved may be those induced by casting, machining, cold working, welding, quenching or normalizing.

Normalizing: Heating a ferrous alloy to a suitable temperature above the transformation range and then cooling in air to a temperature substantially below the transformation range, in order to modify the grain size, render the structure more uniform, & substantially improve the mechanical properties.

Sub-zero Treatment: Cooling hardened steel to a temperature sufficiently below zero (0º C) to promote the transformation of any retained austenite to martensite.