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一、前言南京内燃机配件二厂挺杆的热锻模采用3Cr2W8V钢。模子分为上冲头与下模。上冲头热处理后要求硬度HRC45～50,下模HRC47～52。原来采用常规热处理:1080±10℃,保留25分钟,淬油;560℃±10℃回火60分钟,油冷。热处理后硬度虽然合格,但使用寿命不长。上冲头平均寿命3000次,下模为5000次。为提高3Cr2W8V钢的强度、断裂韧性、疲劳强度,以提高模具寿命,我们曾采用复合热处理:(1)气体氮化+常规热处理;(2)常规热处理+气体软氮
First, the foreword Nanjing internal combustion engine parts factory tappet hot forging die 3Cr2W8V steel. Die is divided into punch and die. After the punch heat treatment requirements hardness HRC45 ~ 50, the next die HRC47 ~ 52. The original conventional heat treatment: 1080 ± 10 ℃, retained 25 minutes, quenching oil; tempering 560 ℃ ± 10 ℃ 60 minutes, oil-cooled. Although the hardness after heat treatment qualified, but the service life is not long. The average life of the punch 3000 times, the next model is 5000 times. In order to improve 3Cr2W8V steel strength, fracture toughness, fatigue strength, in order to improve die life, we have used composite heat treatment: (1) gas nitriding + conventional heat treatment; (2) conventional heat treatment + gas soft nitrogen