9Cr2镁球轧辊在淬火-低温回火处理后,发生断裂。分析表明,因冶金及铸造工艺不当造成组织偏析及夹杂物聚集、在随后的锻造及热处理中进一步增加了组织内应力,最终在应力集中处形成裂纹源,最后导致轧辊断裂。根据事故成因提出了应对措施。 9Cr2 magnesium ball roll quenching - low temperature tempering, the fracture occurred. The analysis shows that due to the metallurgical and casting process caused by tissue segregation and inclusion aggregation in the subsequent forging and heat treatment to further increase the stress within the organization, the final concentration of stress in the formation of crack sources, and ultimately lead to roll fracture. According to the cause of the accident proposed countermeasures.