Hot Deformation Behavior and Processing Map of Cr–Mn–Ni–Mo–N Austenitic Stainless Steels

Abstract

In the present work, the hot deformation behavior of two austenitic stainless steels with different nitrogen is studied by conducting compression tests at the strain rates in the range 0.01–7 s −1 and temperatures in the range 950–1150 °C using a Gleeble thermomechanical simulator. Simultaneously, the constitutive relationship is based on the Arrhenius hyperbolic sine equation and constructs the corresponding thermal processing maps based on dynamic material modeling (DMM).The 23Cr7MnNi2Mo0.93N (0.93 N) steel possesses a higher hot deformation resistance and a higher activation energy of deformation (628.39 kJ mol −1 ) compared to the 23Cr7MnNi2Mo0.45N (0.45 N) steel (315.79 kJ mol −1 ). Dynamic recrystallization occurs predominantly in 0.93 N steels under the conditions tested, the samples with 0.93% nitrogen content exhibit higher peak stresses and more complex rheological behavior. According to the thermal processing maps, the hot working region for 0.45 N steel is 1020 to 1150 °C at strain rates of 0.01 to 0.1 s −1 , while 0.93 N steel is not suitable for processing in the experimental parameter range.