Characterization of hot deformation behavior of 410 martensitic stainless steel using constitutive equations and processing maps

Hot deformation behavior of AISI 410 martensitic stainless steel was investigated by conducting hot compression tests at the temperatures of 900–1150 °C and the strain rates of 0.001–1 s−1. The relation between the flow stress and Zener–Hollomon parameter was successfully analyzed via the hyperbolic sine function under the whole range of deformation condition. Therefore, the value of apparent activation energy and the empirical materials constants of A and n were determined. The values of both strain and stress of peak and steady state flow were related to Zener–Hollomon parameter and pertaining relations were proposed. On the basis of dynamic materials model the power dissipation map and the instability map were developed. The processing map was obtained by superimposition of the power dissipation and the instability maps and the regions having the lowest strain rate sensitivity added for more clarification of low and high workability regions. Optical microscopy observations of prior austenite grains showed that dynamic recrystallization grain size had an adverse relation with Zener–Hollomon parameter. According to grain size measurements, the best relation between dynamic recrystallization grain size and Zener–Hollomon parameter was proposed.