Failure cause analysis on cracking of 12Cr1MoVG steam pipeline
Steam leakage of steam pipeline occurred in a coal chemical enterprise after 10 years service.In order to find the cause of leakage and avoid such situation happening again,after the emergency shutdown of the pipeline,it cut offthe cracking parts and carried out the detailed failure analysis.The cracking parts of steam pipeline were analyzed by macroscopic inspection,non-destructive testing,chemical composition analysis,metallographic analysis,electron microscope analysis and mechanical properties test.The results showed that high temperature creep occurred in the heat affected zone of the base material at the weld of the leakage pipeline,and the cracking was caused by local stress concentration in the diameter reducing part of the pipeline.According to the above reasons,it put forward the reasonable and feasible suggestions on the prevention of weld cracks.