Formability investigations of 15–5 PH stainless steel sheets

In aerospace applications, 1 mm thick 15–5 precipitation-hardened (PH) stainless steel sheets containing 2.2–2.4 wt.% tungsten are used in an age-hardened condition for manufacturing the divergent section of the rocket exhaust nozzle. In the present study, the formability of 15–5 PH stainless steel sheets was investigated under three deformation modes: stretch forming, deep drawing, and stretch flanging. The sheets were age-hardened at 650 °C for 4 hours, followed by forced air cooling. Uniaxial tensile tests were conducted in both as-received and age-hardened conditions to determine mechanical properties and anisotropy. Numerical simulations of limiting dome height, cylindrical cup deep drawing, and hole expansion tests were performed. The numerical predictions showed good agreement with experimental results, with minor deviations attributed to sudden fracture without necking. The material exhibited low-to-moderate stretchability, drawability comparable to AISI 304 and DP600 steels, and superior stretch flangeability compared to AISI 204 stainless steel.