How to prevent the production of quenching stresses during standard model cooling?

So how do you prevent the production of quenching stress during the standard precision mold base cooling?
A tempering should be used to eliminate stress, and after quenching of standard models, boil 30 ~ 60min before cooling treatment, eliminating 15% to 25% quenching stress, stabilizing residual aus, then carried out - 60 ° C conventional cooling treatment or deep cold treatment of -120 ° C.

The lower the temperature, the more the residual austenite transition is the number of martensite, but it is impossible to transform. The experimental results show that the residual austenite accounts for approximately 2% to 5%, and a small amount of residual austenite can make a slow stress and buffer. Since the residual austenite is soft and tough, it can partially absorb the energy of the might's rapid expansion, eliminate phase change stress. After the cold treatment, the standard model is taken out in hot water to heat the temperature, and 40% -60% cold treatment stress can be eliminated. When the temperature rises to room temperature, it should be tempered in time to further eliminate cold treatment stress, avoid forming cold treatment cracks, gaining stable tissue and performance, ensuring that standard precision mold base are not deformable during storage and use.