热处理工艺对高成型性0.1%C-3%Mn中锰钢组织和性能的影响

研究了0.1%C-3%Mn中锰钢的热膨胀模拟相变行为和一步法与二步法ART处理对其显微组织和力学性能的影响。结果表明,二步法ART处理比一步法可产生更多的残留奥氏体,可显著改善钢的成型性能。将实验钢的热轧态试样在740℃预处理后再在660℃~680℃进行ART处理能产生12%~14%的残留奥氏体,使钢的总延伸率高于35%,均匀延伸率高于20%。热处理制度为740℃×0.5 h+670℃×1.0 h的试样具有最佳的综合性能,其屈服强度为470 MPa,抗拉强度为680 MPa,总延伸率为40.7%,均匀延伸率高达25%,冲击吸收功为163 J。

Effect of Heat Treatment Process on Microstructure and Properties of a 0.1%C-3% Mn Medium Manganese Steel of High-formability

The phase transition behavior of 0.1%C-3%Mn medium manganese steel was studied via thermal simulation with L78RITA automatic phase transformation instrument, meanwhile the effect of one-step and two-step austenite reverted transformation (ART) treatment on the microstructure and mechanical properties of the steel were also investigated. The results show that the two-step ART treatment produces more residual austenite than the one-step ART treatment, which can significantly improve the forming property of the steel. The hot rolled steel samples were pretreated at 740℃ and then heated to different temperatures for ART treatment, and it was found that 12%~14% of the retained austenite could be produced after treatment in temperature range of 660℃~680℃, which made the total elongation higher than 35% and the uniform elongation higher than 20% of the steel respectively. The steel heat treated in conditions of 740℃×0.5 h+670℃×1.0 h has the best comprehensive properties, namely the yield strength is 470 MPa, the tensile strength is 680 MPa, the total elongation is 40.7%, the uniform elongation is up to 25%, and the impact absorption energy is 163 J.