不同工艺两相区淬火后高马氏体含量双相钢的显微组织与力学性能

摘要

The effect of quenching time and temperature on the microstructure and mechanical properties of high martensite content dual phase steel was studied by scanning electron microscope, optical microscope, rockwell hardness tester and tensile testing machine.The results show that when the quenching temperature was 785 ℃, with the increase of holding time, martensite in the quenching microstructure increased and ferrite decreased, while carbide particles reduced and solution diffusion took place.The hardness, yield strength and tensile strength of the test steel increased, and the elongation and area reduction decreased.When the quenching temperature was 785-830 ℃ and holding for 30 min, with the increase of quenching temperature, ferrite in the quenching microstructure decreased, however, martensite increased.When the quenching temperature was 815 ℃, the quenching microstructure almost indicated martensite.The hardness and tensile strength of the test steel increased, and the elongation and area reduction decreased.The yield strength increased first and then declined slightly.%采用扫描电镜、光学显微镜、洛氏硬度计、拉伸试验机等研究了两相区淬火时间和温度对高马氏体含量双相钢显微组织和力学性能的影响.结果表明:在785 ℃淬火时,随保温时间的延长,双相组织中马氏体体积分数增加,铁素体体积分数减少,碳化物数量减少并发生固溶扩散,试验钢的硬度、屈服强度、抗拉强度均呈上升趋势,伸长率和断面收缩率均呈下降趋势;在785~830 ℃保温30 min淬火后,随温度升高,淬火组织中铁素体体积分数减少,马氏体体积分数增加,碳化物数量减少,当淬火温度为815 ℃时,组织基本全部为马氏体,试验钢的硬度、抗拉强度均呈上升趋势,伸长率和断面收缩率均呈下降趋势,屈服强度则先上升后略有下降.