锻压技术

高强汽车钢极限尖冷弯表征技术

英文标题：Tight radius bending characterization technology of high-strength automotive steel

作者：黄磊1 2 王青1 2 孙绍广1 2 许磊1 2 周勃1 2 谢广群1 2 吕丹1 2 苏洪英1 2

单位：1. 海洋装备金属材料及其应用全国重点实验室 2. 鞍钢股份技术中心理化检验研究所

关键词：高强汽车钢极限尖冷弯角负荷阈值试样宽度试验速率试验结束条件加工方式预应变方向弯曲方向

分类号：TG386

出版年,卷(期):页码：2025,50(8):82-89

摘要：

分析了极限尖冷弯角的影响因素，选用DP780钢分析试样宽度、试验速率、试验结束条件的影响规律，选用DH780钢分析试样加工方式的影响规律，选用QP980钢分析预应变方向和弯曲方向的影响规律。结果表明：随着试样宽度增加，极限尖冷弯角逐渐降低，当试样宽度增大至约50 mm后，极限尖冷弯角趋于稳定，试验速率小于20 mm·min-1或大于30 mm·min-1时，极限尖冷弯角波动较大；不同负荷阈值的试验结束条件对极限尖冷弯角有影响，选用VDA 238-100—2017规定的负荷阈值法作为试验结束条件容易误判；激光切割和剪切加工方式下极限尖冷弯角的数值分散且偏低，而线切割和剪切后磨削加工方式下结果数值不分散且较高；预应变方向和弯曲方向也对极限尖冷弯角有一定影响。综合考虑试验结果，推荐试样宽度选取60 mm，试验速率选取20~30 mm·min-1，以峰值载荷下降30%作为试验结束条件，采用线切割的方式，并且试验时需注明预应变方向和弯曲方向。

The influence factors of tight radius bending angle were analyzed, selecting DP780 steel to analyze the influence laws of specimen width, test speed and test end condition, selecting DH780 steel to analyze the influence law of specimen machining method, and selecting QP980 steel was selected to analyze the influence laws of pre-strain direction and bending direction. The results show that with the increasing of the specimen width, the tight radius bending angle decreases gradually, when the specimen width increases to about 50 mm, the tight radius bending angle tends to be stable. When the test rate is less than 20 mm·min-1 or greater than 30 mm·min-1, the tight radius bending angle fluctuates greatly. The test end conditions with different load thresholds have an influence on the tight radius bending angle, and selecting the load threshold method specified in VDA 238-100—2017 as the test end condition is likely to lead to misjudgment. The values of the tight radius bending angle are scattered and low by the machining methods of laser cutting and shearing, and the results are not scattered and are relatively high by the machining methods of wire cutting and grinding after shearing. The pre-strain direction and bending direction have a certain influence on the tight radius bending angle. Considering the test results, it is recommended that the specimen width is 60 mm, the test rate is 20-30 mm·min-1, a 30% decrease in the peak load is used as the test end condition, and the wire cutting is used as the machining method. Then during the test, the pre-strain direction and bending direction should be indicated.

基金项目：

作者简介：黄磊（1981-），男，硕士，正高级工程师 E-mail：12285269@qq.com 通信作者：苏洪英（1969-），女，硕士，正高级工程师 E-mail：13898019925@163.com

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