فرایندهای عملیات حرارتی Heat Treatment Processes

This process involves heating the steel to its austenitizing temperature to transform its microstructure to austenite. It is then rapidly cooled (quenched), forming a hard but brittle martensitic structure. To reduce brittleness and improve toughness, the steel is reheated to a lower temperature (tempered), which partially relieves internal stresses and slightly reduces hardness. This treatment results in a desirable combination of high hardness and improved resistance to fracture

سمانتاسیون فرآیندی است که طی آن فولاد کم‌کربن در محیطی غنی از کربن قرار می‌گیرد و در دمای بالا حرارت داده می‌شود تا سطح آن کربن جذب کرده و پس از کوئنچ، سختی سطحی بالا و مغز چقرمه حاصل گردد. این روش برای افزایش مقاومت به سایش و حفظ انعطاف‌پذیری داخلی قطعه استفاده می‌شود.

Carburizing is a heat treatment in which low-carbon steel is exposed to a carbon-rich atmosphere at high temperatures, allowing carbon to diffuse into the surface. After quenching, a hard outer shell with a tough core is formed. This method is widely used to improve surface wear resistance while maintaining core ductility

Nitriding and nitrocarburizing are thermochemical processes that introduce nitrogen (and some carbon in the case of nitrocarburizing) into the steel surface. Carried out at relatively low temperatures without rapid quenching, they create a hard, wear-resistant and corrosion-resistant surface layer, enhancing performance without distortion

These heat treatments aim to soften steel, improve machinability, relieve residual stresses, and homogenize the microstructure. Full annealing involves slow furnace cooling, isothermal annealing maintains a constant holding temperature, and normalizing involves air cooling from the austenitizing temperature to refine grain structure

Martempering and austempering are heat treatment processes used to reduce distortion and residual stresses caused by rapid quenching. In these methods, the steel part is first cooled to a specific intermediate temperature in a hot salt or oil bath. Then, in martempering, the cooling continues slowly; whereas in austempering, the part is held at that temperature for a period of time. Both methods aim to produce a uniform microstructure with high hardness and minimal deformation.