高伸长率冷轧双相钢DP980显微组织及性能

Microstructure and properties of high elongation DP980 cold rolled dual phase steel

为了进一步提高冷轧双相钢DP980的强塑性,采用低C-Si-Mn-Nb-Cr成分,通过调整连续退火工艺参数,系统研究了工艺组织性能的关系,利用OM、SEM、EBSD分析了不同退火温度条件下各相的比例、尺寸、形貌、分布,同时利用力学拉伸试验手段研究了连退两相区退火温度对强塑性的影响。结果表明,通过优化调整连续退火工艺,不仅可以在冷轧铁素体和马氏体双相钢的组织上获得少量的残余奥氏体,也能细化再结晶晶粒,最终获得ReL/Rm≤0.5、高伸长率A50≥15%的冷轧DP980,提高强塑性的同时改善了成型性能。

In order to further improve the strength and plasticity of cold rolled dual phase steel DP980,the relationship between process-structure and properties were systematically studied by adjusting continuous annealing process parameters with low C-Si-Mn-Nb-Cr composition.The proportion,size,morphology and distribution of phases at different annealing temperatures were analyzed by OM,SEM and EBSD,and the effect of continuous annealing temperature on the strength and plasticity were studied by mechanical tensile test.The results show that not only a small amount of residual austenite can be obtained on the structure of cold rolled ferrite and martensite dual phase steels,but also recrystallized grains can be refined by optimizing and adjusting the continuous annealing process.Finally,cold rolled DP980 with high elongation of A50≥15%and less than 0.5 ultra low yield ratio can be obtained,which improves the strength and plasticity as well as the formability.