【摘要】 42CrMo导向套是煤炭行业支护装备中的重要工件。某批导向套在热处理后的机加工过程中出现了裂纹，影响其正常使用。通过金相显微镜和扫描电镜对试样的化学成分、金相组织、夹杂物、断口进行分析，对裂纹的成因进行探究。结果表明，该批次42CrMo导向套表面裂纹为淬火应力裂纹，导向套在淬火过程中淬火温度过高、冷却速度较快、回火不及时导致内应力超过其强度极限产生裂纹。更多还原

【Abstract】 42CrMo guide sleeve is an important workpiece in the coal industry support equipment. A certain batch of guide sleeves appeared cracks in the machining process after heat treatment, which affects its normal utilization. The chemical composition, metallographic organization, inclusions and fracture surface of the specimens were analyzed by metallographic microscopy and scanning electron microscopy to investigate the causes of cracks. The results show that the surface cracks on the 42CrMo guide sleeves of the batch are quenching stress cracks. The guide sleeve in the quenching process temperature was too high, fast cooling rate, and delayed tempering, resulting in internal stress exceeding its strength limit and causing cracks.更多还原