Stahlmantel Gefrierschrank Kältetechnik

Stahlmantel Gefrierschrank Kältetechnik

For the application of the mold industry, the service life and dimensional stability of the mold will affect the use of the mold. What effects can the low temperature technology of the steel jacket freezer achieve?

First, the main factors affecting the service life and dimensional stability of the mold

1. The influence of retained austenite

After quenching, austenite cannot be completely transformed into martensite at room temperature, and the amount of retained austenite hardly changes, but in post-processing and use of molds, such as friction in grinding, electrical machining, and high-speed stamping Heat generation can easily lead to further transformation of retained austenite, and the impact resistance of the mold will deteriorate due to the increased brittleness of the nascent martensite.

At the same time, because the volume ratio of austenite and martensite is different, the instability of retained austenite will lead to the instability of mold size, including the loss of wire cutting positioning accuracy and the decrease of hole verticality, resulting in wire clamping , including changes in precision during mold use and storage.

The post-processing of the mold, including grinding and electrical machining, will generate local high heat on the processed surface, which will cause the transformation of the surface structure of the mold, and the new martensite caused by the surface will increase the brittleness of the mold surface and toughness, and fatigue The resistance is reduced, and at the same time, the wear resistance of the mold is reduced.

2. Influence of residual stress

The residual stress of die quenching comes from two aspects: one is the volume stress caused by uneven heating and cooling; the other is the structural stress caused by martensitic transformation. These two kinds of residual stress are generally tensile stress. The existence of this residual tensile stress reduces the actual bearing capacity of the mold, that is, reduces the fatigue life of the mold; change. At the same time, the redistribution of stress generated during mold processing often makes it difficult to achieve machining accuracy, and even causes mold cracking in severe cases.

Second, the effect that the cryogenic treatment of the steel jacket freezer can achieve

1. Almost all retained austenite is transformed into martensite, and the hardness of the mold is improved;

2. Improved wear resistance;

3. The residual stress is greatly reduced;

4. Improve the processing performance of wire cutting, good precision stability, reduce the verticality deviation of the rough cutting aperture, and cut large or thin pieces without wire clamping;

5. The linear change of mold size caused by room temperature changes can be reduced compared with conventional treatment, which is conducive to the maintenance of high-precision mold dimensions;

6. The service life of the punching notch is significantly improved, which can significantly reduce the cost of the mold.