Effect of Heat Treatment on the Mechanical Property Enhancement of 17-4 PH Stainless Steel for Sheet Forming Applications

17-4 PH stainless steel is a precipitation hardenable material finding notable applications in automotive and aerospace industries. The main requirement of materials for sheet forming application is enhanced ductility with lower strength. In precipitation hardenable alloys, maximizing ductility by optimizing the heat treatment parameters is possible. The present work investigates the influence of heat treatment on the tensile formability of 17-4 PH SS. Experiments were conducted to optimize the heat treatment parameters for improved ductility by performing tensile tests. Microstructure was investigated by light microscope, scanning electron microscopy, electron backscattered diffraction, and x-ray diffraction and correlated to the mechanical properties. The ductility of the as-received sheet increases by similar to 105% after solution heat treatment. Age hardening increases strain hardening exponent, enhancing strain hardening region and ductility. The ductility increased with increase in age hardening temperatures. The ductility of the solution heat-treated sample increases by 166% upon age hardening at 600 degrees C for 4 h. This was mainly due to the presence of reverted austenite during age hardening. Modeling the flow curve using the Kocks-Mecking-Estrin (KME) method revealed a fair correlation (coefficient of correlation, R-2 >= 0.96) with the experimental flow curve. Variation in dislocation density parameters, dislocation hardening, and dislocation recovery, evaluated by the KME approach, reveal that the overall dislocation density decreases during age hardening. This is due to an increase in dislocation recovery parameter. Enhancement in strain hardening region, hardening capacity, and strain hardening exponent in age-hardened conditions results in improved sheet formability.