Near Net Forming Process Optimization of 17-4PH Steel Based on High Temperature Deformation Behaviour and Microstructure Control

Abstract

In this paper, the high temperature deformation behaviour of 17-4PH steel was studied. A new forming optimization method was proposed. The study will help guide the obtainment of high-precision and high-mechanical properties forging products in the aerospace industry. A hot compression test was carried out on a Gleeble1500D test machine (DUFFERS SCIENTFIC, Beijing, China). The stress–strain behaviour at a temperature of 1000 °C~1150 °C and strain rate of 0.1~10 s−1 was analysed. Through the analysis of multiple heating tests, we come to the conclusion that the heating times should be controlled within 1 or 2 times in order to obtain a grain size above grade 6. Optimization analysis of the forming process was carried out to shorten the process and ensure the precision of the product. The preform shape was obtained quickly by fourth-order curve fitting. According to the method of finite element numerical simulation, the near net forming process within two heating procedures was determined. A 17-4PH forging product with precise shape and qualified structure was obtained through actual forming test.