Hot deformation behavior and microstructural evolution of high-carbon high-strength low alloy steel

Abstract

This study investigates the hot deformation behavior, microstructural evolution, and processing map of a high-carbon high-strength low alloy steel subjected to hot compression tests in the temperature range of 850 °C–1150 °C and strain rates from 0.01 s⁻1–10 s⁻1. A highly accurate flow stress constitutive equation has been established and the activation energy of the experiment steel is 462.6 kJ/mol. Processing maps were generated to identify unstable zones, low-power dissipation zones, and optimum processing zones, accompanied by detailed discussions on corresponding microstructures and mechanical properties. The recommended hot deformation parameters at a true strain of 0.9 are temperatures from 944 °C to 1050 °C and strain rates from 0.01 s⁻1 to 0.52 s⁻1 according to the processing map. The effects of deformation temperature and strain rate on the microstructure were then investigated. It is revealed that reducing deformation temperature and increasing strain suppress the recrystallization process and the growth of recrystallized grains; while VC precipitation is suppressed under high temperatures and high strain rates.

Keywords

• High-carbon HSLA steel
• Hot deformation
• Processing map
• Constitutive model
• Microstructure evolution