切割工艺对超高强度钢边部质量及成形性能影响的试验研究

Experimental research on influence of cutting process on edge quality and formability of ultra-high strength steel

选用DP980-1. 6 mm、QP1180-1. 2 mm和MS1180-1. 4 mm 3种超高强度钢材料,研究了冲裁间隙和凸模刃口角度对冲裁断面的影响。结果显示,DP980和QP1180对冲裁间隙的变化更加敏感,在冲裁间隙过大时,毛刺高度明显增大导致断面质量极度恶化。通过切割边部显微硬度的变化,对比了冲裁和线切割两种工艺下边部影响区的大小,结果表明冲裁边部显微硬度值高,且影响区宽度较大。采用基于数字图像相关法的切边拉伸试验,探究了冲裁、冲裁+打磨和线切割3种工艺对边部拉伸性能的影响,冲裁+打磨可以改善边部质量,提高成形性能。同时,发现相较于DP980和MS1180,QP1180具有较好的局部成形性能。

Three kinds of ultra-high strength steel(UHSS),DP980-1.6 mm,QP1180-1.2 mm and MS1180-1.4 mm,were selected to investigate the influence of blanking clearance and punch angle on blanking sheared surface.The results show that DP980 and QP1180 are more sensitive to blanking clearance,and the height of burr increases observably with overlarge blanking clearance which causes poor sheared surface quality.The areas of edge affected zone of blanking and wire electrical discharge maching(WEDM)were compared through the micro-hardness profiles of cutting edges.It is discovered that the micro-hardness in blanking edge is higher and the affected zone is larger.The influence of three cutting processes including blanking,blanking with polishing and WEDM on edge formability were investigated by using sheared-edge tension test based on digital image correlation(DIC)method.The results show that blanking with polishing can improve the edge quality and formability.Meanwhile compared with DP980 and MS1180,QP1180 has a good performance on local formability.