The forging processing plant adopts unconventional heat treatment process, which overcomes the different timeliness of internal and external structures of forgings, reduces the thermal stress and organizational stress, and has obvious effect. The following methods have played an important role in the heat treatment process and saved a lot of energy, which is worth promoting.
1. Surface quenching (induction heating, flame heating, electrolytic heating and quenching, etc.) For example, screw. Screw Spindle and other slender parts can ensure that the surface has enough hardness. High wear resistance and fatigue strength, good internal strength and toughness, and small overall deformation of parts.
2. Deformation heat treatment of forgings.
3. Controlled atmosphere and vacuum heat treatment.
4. Chemical heat treatment of forging factory. If the forging is nitrided and soft nitrided, the chemical composition in the internal and external structures is different, and the temperature is lower than the phase change point, which avoids the possibility of significant deformation after overall quenching. It is applicable to forgings with strict deformation requirements.
5. Ultrasonic quenching. The ultrasonic vibration quenching medium can eliminate the steam film on the surface of the quenched forging, improve the cooling speed, increase the strength of the quenching process, make the cooling more uniform, and avoid soft spots on the surface of the forging. The soft band, internal stress and deformation are significantly reduced.
6. Fast heating. It refers to raising the heating temperature so that the surface of the forging can quickly reach the quenching temperature, and then completing the quenching heat treatment process, such as the rotary heating teeth of the gear in the salt bath furnace or high-frequency heating. Due to the short heating time, the surface austenite grains do not grow, and the quenching surface heat cannot be transferred to the interior, only the surface structure changes, and the deformation is significantly reduced.