屏式过热器弯头爆裂原因分析

Failure analysis of explosion and fracture of platen superheater elbow

通过宏观形貌检验、化学成分检测、力学性能检测、金相检验、断口形貌分析,对发生爆裂的屏式过热器弯头进行了失效原因分析,弯头外侧发生了珠光体严重球化和沿晶开裂,弯头内侧珠光体轻微球化、未见沿晶开裂,弯头爆裂处呈岩石状沿晶断口。结果表明:屏式过热器弯头外侧局部温度过高导致弯头发生了高温蠕变爆裂。

In order to analyze the reasons that the platen superheater elbow fails,the macroscopic morphology,chemical composition,mechanical properties,microstructure and fracture appearance were analyzed and tested. There are serious spheroidization of pearlite and intergranular cracking at the outside of the elbow,but there are slight spheroidization of pearlite and no intergranular cracking at the inside of the elbow. The fracture appearance where the pipe explodes shows the intergranular mode with rock-like. The result indicates that the local high temperature leads to creep at the outer pipe of the platen superheater elbow.