铜含量对超高强度低碳贝氏体钢力学性能的影响

Effect of Cu Content on Mechanical Properties of Ultra High Strength Low Carbon Bainitic Steel

实验用低碳贝氏体钢（％：0．042～0．045C、1．43～1．47Mn、1．0～2．5Cu、0．29～0．30Mo、0．025～0．029Nb、0．011～0．018Ti、0．0013～0．0023B）由50kg真空感应炉冶炼。实验结果表明，随铜含量由1．0％增加至2．5％，8．Cu在钢中沉淀速度加快，峰值硬度增大；随Cu％的增加，轧后直接淬火（DQ）钢的屈服强度由865MPa增至918MPa。DQ＋500℃回火钢的屈服强度由935MPa增至1140MPa，但1．0％～2．5％CuDQ＋500℃回火钢的抗拉强度和冲击韧性均比DQ态钢有所降低。

Test low carbon bainitic steel （0.042～ 0.045C, 1.43～ 1.47Mn, 1.0 ～2.5Cu, 0.29～0.30Mo, 0. 025～0. 029Nh, 0.011～0.018Ti, 0.001 3～0.0023B） was melted by a 50 kg vacuum induction furnaee. Test resuhs showed that with increasing Cu content from 1.0% to 2. 5%, the precipitation speed of ε-Cu in steel and the peak hardness increased; and with increasing Cu% , the yield strength of direct-quenching （DQ） steel after rolling increased from 865 MPa to 918 MPa and the yield strength of DQ ＋ 500 ℃ tempering steel increased from 935 MPa to 1 140 MPa, while the tensile strength and impact toughness of DQ ＋500 ℃ tempering 1.0 ～2. 5Cu steel were lower than that of DQ steel.