The forgings adopt an unconventional heat treatment process, which overcomes the different time characteristics of the internal and external microstructure transformation of the forgings, reduces the thermal stress and the tissue stress, so the effect is obvious. The following methods play an important role in the heat treatment of the forgings, and also save a lot of Energy is worth promoting and promoting.
1. Surface quenching (induction heating, flame heating, electrolytic heating quenching, etc.). For example, the elongated parts such as the screw, the screw and the spindle can ensure sufficient hardness, high wear resistance and fatigue strength of the surface after surface quenching, and the internal strength and toughness are small, and the overall deformation of the part is small.
2. Forging deformation heat treatment.
3. Controllable atmosphere and vacuum heat treatment.
4. Forging chemical heat treatment. For forgings, nitriding, soft nitriding, etc., the chemical composition in the internal and external tissues is different, and its temperature is below the phase transition point, thus avoiding the possibility of significant increase in deformation after the overall quenching, and is suitable for forgings with strict deformation requirements.
5. Ultrasonic quenching. The ultrasonic energy is used to vibrate the quenching medium, which can eliminate the vapor film on the surface of the quenching forging, improve the cooling rate, increase the quenching process severely, and make the cooling more uniform, which can avoid soft spots, soft bands, internal stress and deformation on the surface of the forging. Significantly reduced.
6, fast heating. It refers to the use of increasing the temperature of the heating, so that the surface of the forging quickly reaches the quenching temperature, and then the quenching heat treatment process is completed, for example, the gear rotates in the salt bath furnace to heat the tooth or high-frequency heating, etc., due to the short heating time, the surface is The grain of the solid body does not grow, and the heat of the surface after quenching cannot be transmitted to the inside, so only the surface transformation occurs, and the deformation is remarkably reduced.