Tempering heat treatment temperature range
Random single pulse tempering process. The results show that it is easier to control the random heat treatment energy input accurately by using multi-pulse tempering heat treatment than by using single-pulse tempering heat treatment, and control the tempering heat treatment temperature and temperature field distribution of the spot welding joints more effectively, so that the spring steel resistance spot welding joints can get more sufficient and even tempering heat treatment.
Tempering heat treatment temperature range
According to the temperature range of tempering heat treatment, tempering can be divided into low temperature tempering, medium temperature tempering and high temperature tempering.
1. Low temperature tempering
The workpiece is tempered at 150~250℃. The purpose is to maintain the high hardness and wear resistance of the quenched workpiece and reduce the residual stress and brittleness of the quenched workpiece.
2. Medium temperature tempering
The workpiece is tempered at 350 ~ 500 ℃. The purpose is to obtain higher elasticity and yield point, appropriate toughness. After tempering, tempered troostite is obtained, which refers to the complex phase structure with fine spherical carbides distributed in the ferrite base formed during the tempering of martensite.
3. High temperature tempering
Tempering of workpiece at above 500~650℃. The aim is to obtain the comprehensive mechanical properties of strength, plasticity and toughness. After tempering, the tempered sostenite is obtained, which means that the ferrite base formed during the tempering process is distributed with fine spherical carbides.
