Influences of Heat Treatment Parameters on Microstructure And Mechanical Behavior of TWIP Steel

Abstract

In this study, the effects of different heat treatment temperatures and times on the mechanical properties and microstructure of Twinning Induced Plasticity (TWIP) steel were examined. TWIP steel slabs produced by casting were shaped into plates by hot and cold rolling processes, respectively. The heat treatments were carried out at 600, 700, 800, and 900 °C for 20, 60, and 150 min. As a result of the experiments, M3C carbide precipitates were formed instead of twinning in the tempered sheets at 600 °C and 700 °C, and twinning occurred at 800 °C and 900 °C. The microstructure analysis and mechanical test results demonstrate that the carbide precipitates prevent twinning plane formation. The Vickers hardness and tensile test results showed the intense presence of carbides at 600 °C and 700 °C and twinning at 800 °C and 900 °C. As the annealing temperature and time increased, a decrease in hardness and tensile strength was observed. Elongation increased. However, as a result of annealing at 600 °C for 20 minutes, an increase in elongation and tensile strength was observed compared to the untreated sample.