Compressive Deformation Behavior of Thick Micro-Alloyed HSLA Steel Plates at Elevated Temperatures

다국어 초록 (Multilingual Abstract)

<P>The hot deformation behavior of a heavy micro-alloyed high-strength low-alloy (HSLA) steel plate was studied by performing compression tests at elevated temperatures. The hot compression tests were carried out at temperatures from 923 K to 1,223 K with strain rates of 0.002 s(-1) and 1.0 s(-1). A long plateau region appeared for the 0.002 s(-1) strain rate, and this was found to be an effect of the balancing between softening and hardening during deformation. For the 1.0 s(-1) strain rate, the flow stress gradually increased after the yield point. The temperature and the strain rate-dependent parameters, such as the strain hardening coefficient (n), strength constant ( K), and activation energy (Q), obtained from the flow stress curves were applied to the power law of plastic deformation. The constitutive model for flow stress can be expressed as sigma = (39.8 ln(Z) - 716.6). epsilon((-0.00955ln(Z) + 0.4930)) for the 1.0 s(-1) strain rate and sigma = (19.9ln (Z) - 592.3). epsilon((-0.00212ln(Z) + 0.1540)) for the 0.002 s(-1) strain rate.</P>