Thermal Aging Effect of 17-4PH Martensitic Stainless Steel Valves for Nuclear Power Plant

In this work, impact toughness and tensile properties of valve stem used in NPP are obtained. Combining with microstructure analysis of fracture morphology and metallurgical structure, the thermal aging behavior of the martensitic stainless steel is studied. The results show that the thermal aging embrittlement is significant when the valve stem serves in high temperature for a long time. The ductile to brittle transition temperature (DBTT) and the hardness increase, and the upper platform energy decreases.