WARM-DEFORMATION BEHAVIOR OF 65Mn SPRING STEEL

The warm-deformation behavior of 65Mn spring steel was shown with a thermomechanical simulator. The deformation temperatures were in a range of 550-700 degrees C and strain rates were in a range of 0.001-1 s(-1). The deformation activation energy was calculated to be 486.829 kJ/mol. A strain-compensated Arrhenius-type constitutive model was established. Relationships between material constants and strain were fitted with an 8th order polynomial. It was found that the strain has a significant influence on the instability map. At a strain of 0.4, there were two flow-instability domains. One domain occurred in a temperature range of 550-630 degrees C and a strain-rate range of ln(0.004) - ln(1) s(-1). The other domain occurred at a temperature range of 671-700 degrees C and a strain-rate range of ln(0.09) - ln(1) s(-1).