Study on constitutivemodeling and processingmaps for hot deformation of medium carbon Cr-Ni-Mo alloyed steel

The hot deformation behavior ofmediumcarbon Cr-Ni-Moalloyed steel 34CrNiMowas studied in thewide temperature range of 900-1150 degrees C and the strain rate of 0.002-5 s(-1). The thermo-mechanical analysis using Thermo-Calc software indicates austenite is themain phase during hot compression, which has a high occurrence tendency of DRX because of lowstacking fault energy of such a phase. Constitutive equations for flowstresswere developed by using thework hardening curve for the work hardening and dynamic recovery period and Avrami equation for the dynamic recrystallization period. All the factors in the equations can be illustrated in terms of Zener-Hollomon parameter. Besides, processing maps based on dynamic material model at the strains of 0.2, 0.4, 0.6, 0.8 and 1.0 were established. The concluded optimum hot working parameters are at 950-1100 degrees C & 0.01-0.2 s(-1) and 1100-1150 degrees C & 0.01-5 s(-1). (C) 2015 Elsevier Ltd. All rights reserved.