8Cr5MoV锻钢冷轧辊断裂原因分析

Cause analysis of the fracture of 8Cr5MoV forged steel cold roll

某8Cr5MoV锻钢冷轧辊在使用时发生早期失效断裂,采用化学成分分析、金相检验、断口分析、硬度测试、冲击试验等方法对其断裂原因进行了分析,结果表明,未按要求对辊身进行热处理使辊身整个横截面在终淬(表面淬火)后几乎被淬透,其不符合心部为调质组织、边部有一定厚度隐针马氏体的淬硬层的要求。此外,辊身的心部和表面部分区域网状碳化物级别过高,导致了整个辊身的韧性恶化,造成轧辊的早期脆性断裂。

The early failure fracture of 8Cr5MoV cold roll occurred in use. The fracture reasons were analyzed by means of the chemical composition analysis,microstructure examination,fracture analysis,hardness test and impact test.The results showed that the heat treatment for the roll body,which did not conduct as required,caused the fracture of the whole cross section of the roll body,and the microstructure could not meet the requirement for the hardening layer with the tempering organization in the heart department and a certain thickness of needle martensite on the edge. In addition,the net cementite level was too high in the area of the surface and the core of the roll,and caused the deterioration of the toughness of the roll body,which resulted in the early brittle fracture of cold roll.