Abstract: The change of structure and mechanical properties of Nb-Ti microalloying IF steel （/%: 0.006C, 0. 005Si, 0. 15Mn, 0. 008P, 0. 006S, 0. 039Al, 0. 01Nb, 0. 048Ti, 0.003 4N） during cold rolling process from 3. 98 mm hot rolled plate cold rolling to 0. 4 mm sheet （ deformation 40% to 90% ） by a four cold-rolling mill in laboratory has been tested and studied. Results show that with increasing cold-rolling reduction ratio the grains of Nb-Ti microalloying IF steel gradually decrease and flat, and the secondary phase particles are more arranged to orientate rolling direction, and the hardness, yield and tensile strength of steel increase while the elongation of steel decreases. With deformation 75% and 77% the yield strength-tensile strength ratio is lowest, and the comprehensive mechanical properties of steel could be gotten.

摘要： 试验研究了Nb-Ti微合金化无间隙原子(IF)钢(/%:0.006C、O.005Si、0.15Mn、0.008P、0.006S、0.039A1、0.01Nb、0.048 Ti、0.003 4N)在实验4辊冷轧机由3.98 mm热轧机冷轧至0.4mm(变形量40%～90%)过程组织和力学性能的变化。结果表明,随着冷轧变形量的增加,Nb-Ti微合金化IF钢组织中晶粒逐渐变为细小且纤维化,第二相粒子趋于沿轧制方向排列;钢的硬度、屈服强度、抗拉强度均增加,伸长率下降。变形量在75%和77%时出现低的屈强比,并可获得好的综合力学性能。

关键词: Nb-Ti微合金化IF钢, 冷轧变形量, 组织;第二相粒子, 力学性能