Cryogenic treatment can solve several problems after heat treatment

2024-03-24 10:02:02

Cryogenic treatment can solve several problems after heat treatment

From a macro perspective, cryogenic treatment has the following functions:

Improve the wear resistance of the material

Improve the dimensional stability of the material

Improve the strength, plasticity, toughness, fatigue and other comprehensive properties of the material

Improve the physical and chemical properties of the material such as electrical conductivity, thermal conductivity and corrosion resistance
 

Cryogenic treatment involves a variety of materials, including steel materials, non-ferrous metals and some non-metallic materials (such as plastics, nylon, etc.), for different materials, the mechanism of cryogenic treatment is not consistent.
 

For steel materials, first of all, the transformation of residual austenite to martensite occurs during the cryogenic treatment process, which improves the hardness, strength and dimensional stability of the workpiece. Secondly, due to the shrinkage of martensite matrix volume during cryogenic treatment, the lattice constant of iron tends to shrink, which increases the driving force of carbon atom precipitation. On the other hand, the residual austenite is transformed into martensite at low temperature, and the internal stress of the material increases, which promotes the precipitation of carbide. Therefore, in the subsequent tempering process, a large number of dispersed ultra-fine carbides are precipitated on the martensite matrix, which causes the material to strengthen and greatly improves the wear resistance of the material. In addition, cryogenic treatment can refine the organization and cause the strengthening and toughening of the workpiece, while causing the material internal defects (micropores, internal stress concentration) plastic flow, so that the surface of the material produces residual compressive stress, cryogenic treatment can also partially transfer the kinetic energy of the atom, so that the atoms are more closely combined, improve the performance of the material.