Cause Analysis on Fracture of 304 Stainless Steel Check Valve

The 304 stainless steel check valve on a company's production equipment fractured during use. The fracture causes of the check valve were analyzed by means of macro analysis, chemical composition analysis, fracture analysis, non-metallic inclusion detection, metallographic examination, microhardness test and so on. The results show that the fracture position of the check valve was located at the weld seam, which was one-time overload fracture. Due to the improper weld seam process, there was unwelded defect at the weld seam position, which made the strength of the check valve tube reduce. Under the action of large medium stress, one-time overload fracture occurred.