Stainless steel head due to the inconsistent surface and center cooling rate and time, the occurrence of thermal stress. Stainless steel head the workpiece surface pressure and heart Ministry tension under the action of thermal stress. This phenomenon is cooled velocity, material composition and heat treatment and other factors.

 

Stainless steel during heat treatment due to the change in the organization that is the transformation of austenite to martensite, accompanied by an increase in specific volume expansion in volume of the workpiece, the various parts of the workpiece has a phase change, causing the volume grew inconsistency of the stress.

 

The end result stainless steel head the surface tissue stress is tensile stress, the heart portion compressive stress, and thermal stress exactly the opposite. The stress in the workpiece size and cooling rate of martensite transformation zone factor, shape, chemical composition of the material.

 

Thermal stress before organizational changes it has produced a stainless steel head, and the stress is generated in the organizational transformation process, the entire cooling process, heat stress and the results of the stress combined effects, that is, the work actually present stress . The results of these two combined effects of stress is very complex, being affected by many factors, such as composition, shape, heat treatment and so on. Only two types, namely thermal stress and stress, the role of the opposite direction when the two offset its development process, the role of the same direction both mutual superposition.