冷轧变形量和退火对双相高强度钢DP780应力分布的影响

Effect of Cold-Rolling Percentage of Reduction and Annealing on Stress Distribution of Dual-Phase High-Strength Steel DP780

860℃终轧水冷的3 mm双相钢DP780热轧板(/%:0.09C,0.17Si,1.94Mn,0.009P,0.003S,0.23Cr)分别经单道次压下率1.0%和6.0%冷轧至1 mm板,并经780℃5 h退火处理。利用X射线衍射法及剥层法分别分析了双相高强度钢DP780不同单道次压下率冷轧后和退火后的表层残余应力及厚度方向上残余应力的分布。实验结果表明,单道次压下率对双相钢DP780应力分布影响较大,道次压下率为6.0%时表层残余应力值较大且随着厚度方向的深入,应力值逐渐减小,道次压下率为1.0%时表层残余应力值较小,且随着厚度方向的深入,应力值先增加后减小,两者在厚度中心位置应力都达到最大压应力。退火可以显著减小残余应力,1.0%道次压下率钢板表层残余应力减小了50%,6.0%道次压下率钢板表层残余应力减小了75%,两者在退火完成后厚度方向残余应力分布规律基本一致。

The 3 mm hot-rolled plate finishing rolling at 860 ℃ water-cooling of dual-phase steel DP780 （/% ： 0. 09C, 0. 17Si, 1.94Mn, 0. 009P, 0. 003S, 0. 23Cr） is cold-rolled to lmm sheet respectively with single pass reduction 1.0% and 6. 0% , and annealed at 780 ℃ for 5 h. The distribution of surface residual stress and thickness direction resid- ual stress afte cold-rolling and annealing of dual-phase high-strength steel DP780 with different single pass reduction is ana- lyzed respectively by using X-ray diffraction and peeling method. Test results show that the effect of single pass reduction on distribution of stress in dual phase steel DP780 is great, the surface residual stress of sheet with pass reduction 6. 0% is larger and with increasing the distance along thickness direction the stress gradually decreases, the surface residual stress of sheet with pass reduction 1.0% is smaller and with increasing the distance along thickness direction the stress first increa- ses then decreases, and the compressive stress of center of thickness for both reduction is up to maximum value. The resid- ual stress of sheet reduces markedly by annealing, that is with pass reduction 1.0% the surface residual stress of sheet decreases by 50% and with pass reduction 6. 0% the surface residual stress of sheet decreases by 75% , and after annealing the distribution rule of residual stress along thickness direction with both reduction percentages is about the same. Material Index Dual-Phase High-Strength Steel DP780, Cold Rolling, Pass Reduction, Annealing, Residual Stress Distribution