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我们过去对30CrMnSiNiA钢的预先热处理工艺是:900℃正火后,进行快速退火或低温退火。快速退火工艺是:加热到780℃,保温至透烧后,随炉冷至650℃保温2小时后空冷,硬度HB202。低温退火是:加热至680～700℃保温2～5小时后空冷,硬度HB222。由于硬度高铣削加工困难。我们通过很长时间摸索后,采取装箱用生铁屑保护退火的工艺,解决了铣削困难问题。工艺为:加热到850℃,保温至透烧后(6～7小时),随炉冷至400℃以下出炉空冷。这样处理后硬度为HB177左右,铣削加工的速度提
We used to pre-heat treatment of 30CrMnSiNiA steel is: 900 ℃ normalizing, rapid annealing or low-temperature annealing. Rapid annealing process is: heated to 780 ℃, heat to thoroughly baked, with the furnace cooled to 650 ℃ for 2 hours after cooling, hardness HB202. Low-temperature annealing is: heated to 680 ~ 700 ℃ for 2 to 5 hours after cooling, hardness HB222. Milling difficult due to high hardness. After a long time of exploration, we adopted the process of packing annealing with pig iron to solve the problem of milling difficulties. Process is: heated to 850 ℃, heat to thoroughly after burning (6 to 7 hours), with the furnace cooled to below 400 ℃ baked air-cooled. This treatment after the hardness of about HB177, milling speed mention