Liquid nitrogen machine cryogenic treatment process

When we mention the concept of heat treatment, many people think of a process of heating steel to a certain temperature and keeping it warm, and then cooling it to change the structure of the steel to improve the properties of the steel. However, it is not always the case. Heating the steel to a high temperature and then cooling it is a heat treatment process, and it is also a heat treatment process to heat the steel to a low temperature of minus 100°C and keep it at a low temperature for a period of time. Therefore, heat treatment is not only for heating steel, but also for low-temperature treatment of steel, which is called heat treatment.

The role of liquid nitrogen cryogenic treatment equipment:

1. Changes in retained austenite: At low temperatures (ie below the Ms point) retained austenite continues to undergo phase transformation and transforms into martensite, which improves the hardness and strength of the workpiece, thereby improving the size change of precision molds after a period of use question;

2. Precipitation of ultrafine carbides from martensite: Because the martensite matrix structure is cryogenically treated, the lattice constant of iron tends to shrink due to volume shrinkage, thereby increasing the driving force for the precipitation of carbon atoms; on the other hand At low temperature, the retained austenite is transformed into martensite, the internal stress of the material increases, and the precipitation of carbides is also promoted.

3. Liquid nitrogen machine tissue refinement: tissue refinement causes the workpiece to be toughened.

4. Cause the plastic rheology of the internal defects of the liquid nitrogen machine material (micropores, the inner part should be concentrated) to avoid the failure of the workpiece defects.