30CrMo钢管件热加工鼓起失效分析

Failure Analysis on Bulging of 30CrMo Pipe during Hot Processing

采用宏观检验、化学成分分析、金相检验、扫描电镜和能谱分析等手段,对某30CrMo钢管件鼓起失效的原因进行了分析。结果表明:管件热加工过程中炉温的异常波动或管件剧烈摩擦使得管件温度过高,氧侵入晶界或原缺陷(如裂纹)处产生严重氧化脱碳甚至过烧,使得管件材料脆化,并且热旋压刮板的轻微松动使管件变形时受力不均,最后导致管件热压缩过程中在管件脆化区域产生鼓起和折皱失效。

Failure reason of bulging on a 30CrMo pipe was analyzed by means of macroscopic examination. chemical composition analysis, metallographic examination. SEM and EDS analysis. The Ft.,subs showed that the over high temperature was caused by unstable temperature of stove or the friction of pipe in hot processing, the oxygeu intruded into the grain boundary and the defect such as crack, and caused oxidalion decarbonization and overburnning, then embrittlement was happened in the pipe. On the other hand. the loose of hot spinning scraper led to the uneven forces during pipe deformation. Finally, the wall of pipe was bulged and folded at the embrittlement area during hot processing.