The heat treatment process as we know that it is defined as the process which is done to increase the strength as well as ductility and brittleness of the materials. This also helps to lower the residual stresses and internal stresses.
Heat treatment is also used to manufacture of any other material such as glass.
Heat treat mainly involves the following process.
lets see them –
Annealing
It is the process that is done to alter the chemical properties of the material, it is done basically to improve the ductility of the material and to reduce the hardness of the material.
The material is heated above the recrystallization temperature and then maintaining a suitable temperature followed by cooling. Materials such as copper, steels, silver are annealed to increase there ductility.
Case hardening
It is also known as surface hardening, as the name suggests it is done to harden the surface of the material and allowing the surface beneath to remain soft.
Hardening is done for the metals which are subjected to the sliding contact with hard or abrasive material as the hard material offers more resistence to surface wear.
Tempering
It is a process of heat treating, which is used to increase the toughness of iron-based alloys.
it is usually performed after hardening to reduce some of the excess hardness , the material is heated below the critical point and followed by the cooling in air. It increases the toughness by decreasing the hardness of the alloy.
Tempering is usually performed after quenching, which means the rapid cooling of the material.
Quenching
It generally refers to the process in which the materials are cooled specifically by the immersing in the water, oil or forced air.
The hardness of the quenched steel on both cooling speed and composition of the alloy.
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