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本文分析了以往用cr_(12)MoV钢制造的冲压模具损坏的原因:1.由于锻造温度掌握不好,锻件在退火和机械加工后出现裂纹造成的废品;2.有些模具在使用时窝的外径和底部由于裂纹、掉渣和下沉现象;只冲几百个滚子就报废了。从金相组织分析看出:1.由于锻件没有经过反复镦粗,使原材料中二次碳化物末被击碎,产生碳化物不均匀、偏析和纤维流向顺丝的现象。2.由于淬火温度较低,模具强度不够;窝的底部产生被压沉现象等上述原因造成的废品。改进的方法是:1.严格控制锻造时的加热,始锻和终锻温度,加热温度为1050～1100℃;始锻温度;1000～1050℃,终锻温度840～880℃、2.反复镦拔三次使原材料二次碳化物被击碎,减少碳化物偏析,得到合理的纤维流向;3.严格控制淬火温度为1110℃,油冷;淬火后硬度为HRc40～45,回火温度510～520℃,回火2～3次,空冷。回火后硬度为HRc60～62。按这种方法加工的模具,其寿命稳定在5000～30000个,比原来同样材料模具提高8～10倍。较GCr15钢制模具提高3～5倍。
In this paper, the reasons for the damage of the stamping die made of cr 12 MoV steel in the past are analyzed as follows: 1. Waste products caused by cracks caused by forging after annealing and machining due to poor control of forging temperature; Outside diameter and bottom due to cracks, dregs and sinking phenomenon; only washed hundreds of rollers scrapped. Metallographic analysis shows that: 1. Forging does not undergo repeated upsetting, so that the end of the secondary carbide carbide is crushed, resulting in uneven carbide, segregation and fiber flow along the wire. 2. As the quenching temperature is low, mold strength is not enough; the bottom of the nest was sinking phenomenon caused by the above reasons caused waste. Improved methods are: 1. Strict control of the heating forging, forging and final forging temperature, heating temperature of 1050 ~ 1100 ℃; forging temperature; 1000 ~ 1050 ℃, final forging temperature 840 ~ 880 ℃, 2. Repeated upsetting Pull three times so that the secondary carbide crushed raw materials to reduce carbide segregation, to obtain a reasonable fiber flow; 3. Strictly controlled quenching temperature of 1110 ℃, oil cooling; hardness after quenching HRc40 ~ 45, tempering temperature 510 ~ 520 ℃, tempering 2 to 3 times, air-cooled. After tempering hardness HRc60 ~ 62. According to this method of processing mold, its life expectancy stable at 5000 ~ 30000, than the same material mold to improve 8 to 10 times. Than GCr15 steel mold increased by 3 to 5 times.