P80高级塑料模具钢热处理生产工艺的试验研究

对比研究淬火回火工艺及正火回火工艺对P80沉淀硬化塑料模具试验钢组织及硬度的影响。结果表明:20 mm方块试样淬火后得到马氏体组织,正火后得到马氏体与少量贝氏体组织;随着回火温度的提高,硬度先升高后降低,500℃回火时硬度最高,但淬火回火试样的最高硬度(45 HRC)高于正火回火试样(42 HRC);100 mm方块试样在淬火加500℃回火后主要是板条回火马氏体组织,硬度范围为42~45 HRC,平均硬度为44 HRC;正火加500℃回火后主要是板条贝氏体组织,硬度范围为39~43 HRC,平均硬度为41 HRC。实际生产中采用热轧控冷加回火工艺生产P80的厚钢板能够满足用户的硬度要求。

Study of Heat Treatment Production Technology of P80 High-grade Plastic Die Steel

The results of the contrastive studies of the effects of quenching-tempering and normalizing-tempering technology on microstructure and hardness of precipitation hardening plastic die steel P80 show that martensite is obtained after quenching and martensite and few bainite is obtained after normalizing in 20 mm block test samples. Along with the rise of tempering temperature, hardness rises at first and reduces afterwards. The hardness attains the peak value as tempering temperature at 500 ℃. The hardness of the quenching-tempering test sample （45 HRC） is higher than the normalizing-tempering test sample （43 HRC）. Lath tempering martensites and bainites are obtained after quenching and tempering at 500 ℃, with the hardness range within 42-45HRC and the average hardness is 43 HRC in 100 mm block test samples. Lath tempering bainites are obtained after normalizing and tempering at 500 ℃, with the hardness range within 39-43 HRC and the average hardness is 41 HRC in 100 mm block test samples. Quenching-tempering technology can substitute for normalizing-tempering in actual production of P80 steel plate with thickness satisfying users＇ required hardness.