Failure Analysis on Tube Socket Crack of Supercritical Boiler Water Wall Header

Through methods, such as microscope analysis, mechanical analysis, chemical analysis, metallography examination and scanning electron microscope etc, the causes resulting in lots of tube socket cracks of supercritical boiler water wall header (15CrMo) have been analyzed. The result indicates failure of the supercritical boiler water wall header tube sockets are the ductile fracture and belong to thermal stress crack. The unreasonable structure, excessive thermal stress between header and sockets are the primarily inducement of crack failure.