某导电辊在运行一段时间后发生断裂,采用宏观观察、化学成分分析、硬度测试、力学性能测试、金相检验、扫描电镜和能谱分析等方法对导电辊断裂原因进行分析。结果表明:该导电辊辊轴的断裂性质为多源疲劳断裂,断裂源的形成与辊轴和辊筒焊接圆弧处发生的严重晶间腐蚀有关,而该晶间腐蚀是导电辊工作时的强酸性环境和焊接热影响区发生的“敏化”反应共同作用导致的。

A conductive roller fractured after running for a period of time. The fracture causes of the conductive roller were analyzed by means of macroscopic observation, chemical composition analysis, hardness test, mechanical property test, metallographic examination, scanning electron microscope and energy spectrum analysis. The results show that the fracture property of the roller shaft of the conductive roller was multi-source fatigue fracture. The formation of the fracture source was related to the serious intergranular corrosion at the welding arc of the roller shaft and the roller, and the intergranular corrosion was caused by the strong acidic environment of the conductive roller and the 'sensitization' reaction in the welding heat affected zone.