Analysis Cause of Cracking at Inner Wall of Boiler Header Cylinder

The crack cause at inner wall of boiler header cylinder was analyzed by macroscopic examination, chemical composition analysis, mechanical properties test, metallographic analysis, fracture analysis, spectrum analysis and comprehensive analysis. The results show that the crack at inner wall of boiler header cylinder was manufacture defect, which was formed in the steel pipe manufacturing process. Finally, the preventive measures are put forward for cracking cause.