精轧后冷却速度对700MPa级带钢残余应力及组织影响的实验研究

通过实验室轧制、电镜观察、残余应力和力学性能测试,研究了精轧后不同冷却速度对700MPa级高强度带钢残余应力和组织性能的影响。结果表明,带钢的残余应力均为压应力,奥氏体转变后的产物与奥氏体膨胀系数差别大的带钢所测得的残余应力值较大,反之,残余应力值较小;典型的析出相均为聚集析出,随着冷却速度的减缓,析出相的尺寸开始变大。在精轧后不同冷却速度下高强度带钢的强度和残余应力的变化趋势是一致的。因此,要适当控制精轧后的冷却速度,在降低残余应力的同时,满足其强度要求。

Experimental analysis on the effect of cooling rate after finishing rolling on residual stresses and microstructure in the 700MPa grade strip

The effect of cooling rate after finishing rolling on residual stress and microstructure in high-strength steel strip was investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM) and test of little hole method and mechanical properties.The results showed that the residual stress of different cooling rate after rolling was mainly compressive stress,and the residual stresses diminished with slowing cooling rate.The typical morphology of precipitation is mass precipitation,With the decrease of the cooling rate,the size of the precipitation increased,and that with the slowness of cooling rate,both the intensity and residual stress decreased in high strength steel strip.Result of this investigation property through control of cooling rate after finishing rolling.