On the basis of failure analysis, new heat treating processes to raise service life of nut cold heading dies made of AISI-D2 steel were exploited. All of the experiment was carried out in a factory. According to actual service life, the effects of pretreating and processing parameters upon the combination of strength and toughness of the steel were discussed. The experimental results showed that the performance of the dies could be appreciably increased through homogenizing original microstructure, controlling austenitizing conditions and the tempered hardness. It is a key point of the process to coordinate the relationship among matrix composition, undissoved carbide and retained austenite. By means of the new process, the service life of the dies was raised by more than ten times.
展开▼
