Fracture Analysis on Safety Vavle Spring of Power Plant Boiler Drum

Based on macro-structure inspection,chemical composition analysis,hardness test,metallographic structure and fracture morphology analysis,the fracture of safety valve spring of power plant boiler drum was analyzed.The results show that unsuitable material and incorrect heat treatment make spring brittle fracture.The surface corrosion of the spring that oxidized by water occurred during operation,which can accelercate the fracture.