摘要
通过金相显微镜、洛氏硬度计和直读光谱仪对纵向开裂的45钢销轴进行分析。结果表明,45钢销轴的化学成分满足标准要求,裂纹处及其附近的非金属夹杂物较少,显微组织为回火马氏体。裂纹两侧均未见明显脱碳现象,为典型的淬火裂纹。销轴的淬火加热温度偏高,淬火时在水中的冷却时间又过长,销轴直径∅7 mm位于45钢水淬时产生淬火裂纹的危险尺寸范围内,这些因素的综合作用导致销轴产生纵向淬火裂纹。为了防止45钢销轴产生淬火裂纹,应根据45钢的实际临界温度Ac 3制定淬火加热温度,淬火时严格控制销轴的水冷时间,或者采取亚温淬火工艺。
Longitudinal cracked 45 steel pin shaft was analyzed by metallographic microscope,Rockwell hardness tester and direct-reading spectrometer.The results show that the chemical composition of the 45 steel pin shaft meets the standard requirements,the non-metallic inclusions near and at the crack are few,and the microstructure is tempered martensite.No obvious decarburization is found on both sides of the crack,which is a typical quenching crack.The quenching heating temperature of the pin shaft is high,the cooling time in water during quenching is too long,and the diameter∅7 mm of the pin shaft is within the dangerous size range for quenching cracks in 45 steel during water quenching.The comprehensive effect of these factors leads to the longitudinal quenching crack of the pin shaft.In order to prevent the quenching crack of 45 steel pin shaft,the quenching heating temperature should be formulated according to the actual critical temperature Ac 3 of the 45 steel,the water cooling time of the pin shaft should be strictly controlled during quenching,or intercritical hardening process should be taken.
作者
金丽君
代玉杰
毕高杰
Jin Lijun;Dai Yujie;Bi Gaojie(Qingdao Choho Industrial Co.,Ltd.,Qingdao Shandong 266705,China;Qingdao Gold Chain Detection Technology Service Co.,Ltd.,Qingdao Shandong 266705,China)
出处
《金属热处理》
北大核心
2025年第8期301-305,共5页
Heat Treatment of Metals
关键词
45钢
销轴
淬火裂纹
亚温淬火
45 steel
pin shaft
quenching crack
intercritical hardening
