15-5PH (Precipitation hardening) stainless steel is a martensitic precipitation hardening material with high strength, relatively good ductility and excellent corrosion resistance. This steel is widely used for structural and infrastructural applications, such as marine facilities, aircraft fittings and nuclear plants. The steel contains approximately 3 mass% Cu and it is usually used after a simple solution treatment followed by aging in the temperature range of 480-620℃. The aging treatment leads to strengthening of the material due to the formation of highly dispersed nanometric-sized Cu precipitates in the martensite matrix.
The chemical composition of 15-5PH stainless steel is listed: 0.03 mass% C, 0.53 mass% Mn, 0.38 mass% Si, 0.03 mass% P, 0.005 mass% S, 15.83 mass% Cr, 5.33 mass% Ni, 0.28 mass% Nb, 3.19 mass% Cu, balance mass% Fe.