精冲剪切面质量评价及对边部成形性的影响
Quality evaluation of fine blanking shear surface and influence on edge formability
王雪听 1韩非 1庄新村2
作者信息
- 1. 宝山钢铁股份有限公司中央研究院,上海 201900
- 2. 上海交通大学 材料科学与工程学院 塑性成形技术与装备研究院,上海 200030
- 折叠
摘要
为研究精冲剪切面质量对边部成形性的影响,研究了不同冲裁间隙下 16MnCr5 钢、C20E钢和C35R钢 3 种材料的精冲剪切面质量及扩孔性能.结果显示,随精冲间隙的增加,3种材料的精冲剪切面光亮带比例逐渐降低,对应的扩孔试样的极限扩孔率也逐渐降低.对比精冲、普冲、铣削工艺的扩孔试样发现:普冲剪切面的光亮带比例远低于精冲,但其极限扩孔率与 0.1 mm冲裁间隙下的精冲扩孔试样的结果接近;在光亮带比例均为100%的情况下,铣削工艺获得的极限扩孔率为精冲工艺的 2.3～8.8倍,说明剪切面光亮带比例与材料扩孔性能无线性关系,冲裁过程中材料分离引起的材料损伤是影响材料边部成形性能的关键因素.实验测试了毛刺朝向改变和反顶力增加后精冲扩孔试样的极限扩孔率变化,结果显示,相比静水压应力增加带来的损伤值降低,毛刺朝向改变对极限扩孔率的提升更为显著.研究表明,减小冲裁间隙或增加剪切区域静水压力可有效提高剪切面光亮带比例,但光亮带比例增加对材料边部成形性能力提升有限,减少冲压过程中边部累积的损伤是减轻边部开裂风险的有效手段.
Abstract
In order to investigate the influence of fine blanking shear surface quality on edge formability,the fine blanking shear surface quality and hole expansion performance of three materials,namely 16MnCr5 steel,C20E steel and C35R steel,under different blanking clearances were investigated.The results show that as the fine blanking clearance increases,the proportion of bright band on the fine blan-king shear surface of the three materials gradually decreases,and the corresponding limit hole expansion rate of the hole expansion speci-mens also gradually decreases.Compared with the hole expansion specimens processed by fine blanking,ordinary blanking and milling processes,it is found that the proportion of bright band on the shear surface of ordinary blanking is much lower than that of fine blanking,but its limit hole expansion ratio is close to that of the hole expansion specimens by fine blanking with a blanking clearance of 0.1 mm.When the proportion of bright band is 100%,the limit hole expansion rate obtained by milling process is 2.3-8.8 times that of the fine blanking process.This indicates that there is no linear relationship between the proportion of bright band on the shear surface and the hole expansion performance of the material,and the material damage caused by material separation during the blanking process is the key factor affecting the edge formability of the material.The changes in the limit hole expansion ratio of the hole expansion specimens by fine blan-king after the burr direction is changed and the counter force is increased are experimentally tested.The results show that compared with the reduction in damage value caused by the increase in hydrostatic stress,the change in burr direction has a more significant effect on the improvement of the limit hole expansion rate.The research indicates that reducing the blanking clearance or increasing the hydrostatic stress in the shear zone can effectively enhance the proportion of bright band on the shear surface,but the increase in the proportion of bright band has limited improvement to the edge formability of the material,and reducing the cumulative edge damage during the stamping process is an effective measure to mitigate the risk of edge cracking.
关键词
精冲/光亮带比例/扩孔/边部成形性/损伤Key words
fine blanking/ratio of bright band/hole expansion/edge formability/damage引用本文复制引用
出版年
2025
NETL
NSTL
万方数据