宝钢高强钢V弯回弹的特性研究

V-type bending springback characteristics of Baosteel's high strength steel

以宝钢生产的14种规格和牌号的钢板为研究对象,对其V弯成形特性进行了研究,通过单向拉伸实验,获得材料的基本力学性能,分析了试验材料的V弯回弹规律。试验结果表明,材料存在正、负回弹,相同弯曲角度下随弯曲半径增大,回弹量增加且趋向正回弹,在相同弯曲半径下,弯曲角度增大,回弹量减小且趋向负回弹,可通过调整弯曲角度或弯曲模具圆角大小来可合理控制零件回弹;在相同厚度条件下,当材料抗拉强度大于600 MPa时,回弹量显著增大;在相同强度条件下,回弹量随弯曲角度的增大而趋向负回弹,同时随着弯曲半径的变大,回弹量随材料厚度产生的差异趋缓,并趋向正回弹;980 MPa强度级别材料中材料厚度越小,不同弯曲半径下的回弹量差异变大;厚度相同的情况下,QP钢和MS钢的回弹量比DP钢更趋向于正回弹;数值拟合发现,回弹角度随R/T值的增大而增大,且经历一个由负到正的过程。随着弯曲角度的增大,拟合曲线下移且斜率变小,只有当R值足够大时才会出现正回弹。

The V-type bending springback characteristics of fourteen kinds of high strength steel sheets produced by Baosteel were studied. The mechanical properties were obtained by uniaxial tension tests and the springback law of V-type bending was analyzed. The experiment results show that the positive and negative springback are found. At the same bending angle,with the increase of bending radius,the amount of springback increases and shows positive trend. At the same bending radius,with the increase of bending angle,the springback decreases and shows negative trend. The springback of the parts can be controlled reasonably by adjusting the bending angle or the radius of mould fillet. At the same thickness,if the material tensile strength is greater than 600 MPa,the springback increases significantly; at the same strength,the springback shows negative trend with the increasing of bending angle,and with the increase of bending radius,the springback difference induced by material thickness slows down and the springback shows positive trend. For 980 MPa grade material,the springback difference under different bending radii increases with the decrease of thickness,and the springback of QP steel and MS steel show positive trend more obviously than that of DP steel; the numerical analysis shows that the springback increases from negative to positive with the increase of R/T values. With the increase of the bending angle,the fitted curve moves down and the slope becomes smaller,and when the R value is large enough,the springback can be positive.