How to choose the temperature of high frequency quenching and ice cold treatment
First, the selection of the temperature of the high-frequency quenching and ice-cold treatment is mainly carried out according to the Ms and Mf point temperatures of the steel, and is also related to the technical requirements of the parts. Ms<T<Mf. The lower the temperature is not the better, as long as it can meet the technical requirements. In addition, pay attention to the cooling speed of the ice-cold treatment, neither too fast nor too slow.
Secondly, the temperature is not as low as possible, and the cold temperature should be selected according to the actual application! For example, for the cryogenic treatment of bearing rings, the Mf point should be about minus 70 to 80 degrees, and the maximum can reach minus 80 degrees. Therefore, dry ice is selected as the material for cryogenic treatment, which is already sufficient for use.
Cryogenic issues: Tool and die steel -180℃ (liquid nitrogen), general structural steel can be cryogenically cooled to -80℃ (refrigerator). Perform deep cooling. After the cryogenic cooling, wait for the workpiece to rise to room temperature before tempering.