微量残留元素铬、镍和铜对SPHC冷轧带钢组织和拉伸性能的影响

Influences of Trace Residual Elements Cr,Ni and Cu on Microstructures and Tensile Properties of SPHC Cold-Rolled Strip

采用拉伸试验、微观形貌观察和能谱分析等手段,研究了微量残留元素铬、镍和铜对SPHC冷轧带钢组织和拉伸性能的影响。结果表明:随残留元素当量增加,带钢的室温组织和平均晶粒尺寸无明显变化;随着冷轧累积压下率增大,带钢的抗拉强度逐渐增加,当冷轧累积压下率大于70%后,抗拉强度显著增加;当冷轧累积压下率相同时,随着残留元素当量增加,抗拉强度基本呈先升高后降低的趋势;第三道次冷轧后,残留元素在晶界上的偏析量较高时,带钢的抗拉强度明显偏高;残留元素当量应控制在0.02%以下,且应尽量减少残留元素铜的含量,以减小其对带钢拉伸性能的影响。

The influences of trace residual elements Cr, Ni and Cu on microstructure and tensile properties of SPHC cold rolled strips were studied by means of tensile test, morphology observing and energy dispersive spectroscopy. The results show that with the increase of residual elements equivalent, the microstructure at room temperature and average grain size of the strip had no obvious changes. With the increase of cold rolled reduction ratio, the tensile strength gradually increased. When the cold rolled reduction ration was more than 70%, the tensile strength increased significantly. When the cold rolled reduction ratio was same, with the increase of residual elements equivalent, the tensile strength increased firstly and then decreased. There was more segregation of residual elements on the grain boundary after the third pass cold rolling, tensile strength increased significantly. To reduce the bad effect of residual elements on tensile properties, the residual elements equivalent should be kept under 0.02%, especially, the content of residual element Cu should be decrease as far as possible.