Application Aims to steel and non-steel materials in order to decrease the permanent inner stress occurred during welding, cold forming, machining. If this isn’t applied , latter processes may cause unacceptable shape deformation and/or cracks related to stress and corrosion. The application doesn’t aim significant changes on the material’s structure or mechanical properties , fort his reason the process is limited within lower temperatures.
2 types of heat treatment may be applied to carbon and alloyed steel:
(1)Heat treatment at 150 - 200°C relieves high stress while not significantly changing the hardness after hardening.(i.e. carburized parts,bearings etc..)
(2) Heat treatment at 600-680°C provides complete stress relieving(i.e.post welding or machinig etc..)
Austenitic stainless steels are stress relieved below 480 °C or over 900°C, steels which aren’t stabilized on the mid temperatures loses corrosion resistance. Temperatures over 900°C are generally solution annealing treatment.
Waiting temperature is generally 2*-3 minutes for every mm thickness but it is widely accepted as 30 minutes after the core of the part is heated.
The yield of the material decreases as 20-60N/mm2, due to this reason the material starts to be deformed as the inner stress is greater than the yield at that temperature. Therefore inner stress is decreased to yield level at that temperature.