1. Pre-heat treatment on the market supply of H13 steel and mold billet, in the steel mills have been made to heat treatment, to ensure a good microstructure, the appropriate hardness, good processing, no need for annealing. But the factory to change the forging after the destruction of the original organization and performance, increased forging stress, must be re-annealed.
Isothermal ball annealing process: 860 ~ 890 ℃ heating insulation 2h, cooling to 740 ~ 760 ℃ isothermal 4h, the furnace cooled to about 500 ℃ baked.
2. Hardening and tempering requirements Good toughness of the mold quenching process specifications: heating temperature 1020 ~ 1050 ℃, oil cooling or air cooling, hardness 54 ~ 58HRC; requirements of the thermal hardening of the main mold quenching process specifications, heating temperature 1050 ~ 1080 ℃, Oil cold, hardness 56 ~ 58HRC.
Recommended tempering temperature: 530 ~ 560 ℃, hardness 48 ~ 52HRC; tempering temperature 560 ~ 580 ℃; hardness 47 ~ 49HRC.
The tempering should be done twice. In the 500 ℃ tempering, the secondary hardening peak tempering, tempering hardness of the highest peak at 55HRC, but the worst toughness. Therefore, the tempering process should be avoided about 500 ℃ is appropriate. According to the needs of the mold, in the range of 540 ~ 620 ℃ tempering better.
Quenching heating should be preheated twice (600 ~ 650 ℃, 800 ~ 850 ℃), in order to reduce the heating process to produce thermal stress.
3. Chemical heat treatment H13 steel if the gas nitriding or nitrocarburizing can further strengthen the mold, but its nitriding temperature should not be higher than the tempering temperature, in order to ensure that the strength of the heart does not reduce, thereby improving the service life of the mold.
Hubei Kaixin Supply Chain Management Co., Ltd.
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