U型铜材连挤连展工艺产品极限尺寸的研究  

Research on limit size of U-shaped copper produced by continuous extrusion and continuous flattening process

作　　者：马旭东 赵颖[1] 运新兵[1] 刘元文[1] 裴久杨[1] 易飞 MA Xudong;ZHAO Ying;YUN Xinbing;LIU Yuanwen;PEI Jiuyang;YI Fei(Engineering Research Center of Continuous Extrusion,Ministry of Education,Dalian Jiaotong University,Dalian 116028,China;Dalian Konform Technical Company Ltd.,Dalian 116028,China)

机构地区：[1]大连交通大学连续挤压教育部工程研究中心,辽宁大连116028 [2]大连康丰科技有限公司,辽宁大连116028

出　　处：《材料科学与工艺》2022年第4期86-96,共11页Materials Science and Technology

基　　金：辽宁省教育厅项目(JDL2019001);大连市科技创新基金项目(2018J11CY027);辽宁省科技攻关计划项目(2021JH1/10400080)。

摘　　要：采用U型模具连续挤压铜板带时,U型产品尺寸的变化对连续挤压成型过程会产生较大的影响。为了降低模具研发成本,本文通过有限元模拟与解析法得到了U型产品可挤压的极限尺寸。采用有限元法与理论计算研究了不同几何参数比(厚度挤压比λ_(1)、直径扩展比λ_(2)、产品宽厚比λ_(3))对U型连续挤压产品的流速均方差(SDV)以及模具型腔压力σ_(x)、挡料块应力p_(d)和挤压轮扭矩T的影响规律,并建立了模具型腔内接触应力和挤压轮扭矩的函数模型。研究表明:随着λ_(1)的增大,出口截面的速度差越来越大,SDV值增加幅度明显;λ_(2)增大,流速最快区域从U型两侧转移至圆弧处,SDV值变化范围不大。通过主应力法计算得到U型模具腔体内压应力σ_(x)与产品尺寸r_(0)的函数,利用上限法求解出挡料块应力p_(d)与腔体进料口压力p_(k)的关系。将SDV、p_(d)、T作为挤压极限厚度的判定标准,当坯料直径为30 mm,展平宽度为420 mm时,得到可挤压的极限厚度为7 mm。U型铜带连续挤压实验表明,实验结果与理论扭矩对比,误差可控制在10%以内,证明了理论计算极限尺寸的可行性与准确性。When using U-shaped dies to continuously extrude copper strips,the changes in the size of the U-shaped products have a great impact on the continuous extrusion molding process.In order to reduce the cost of mold research and development,the extrudable limit size of U-shaped products was obtained through finite element simulation and analytical method.The finite element method and theoretical calculation were adopted to investigate the influences of different geometric parameter ratios(thickness extrusion ratioλ_(1),diameter expansion ratioλ_(2),and product width-thickness ratioλ_(3))on the mean square deviation of flow velocity(SDV)of U-shaped products by continuous extrusion,die cavity pressureσ_(x),stopper block stress p_(d),and torque T of extrusion wheel.The function model of the contact stress in the die cavity and the torque of the extrusion wheel was established.Research results show that with the increase inλ_(1),the velocity difference at the outlet section became larger,and the SDV value increased significantly;with the increase inλ_(2),the area with the fastest flow velocity shifted from the two sides of the U-shape to the arc part,and the SDV value varied in a small range.The function of the pressureσ_(x) in the U-shaped die cavity and the product size r_(0) was obtained by principal stress method,and the upper limit method was used to solve the relationship between the stopper block stress p_(d) and the cavity inlet pressure p_(k).Taking SDV,p_(d),and T as the criteria for determining the ultimate thickness of extrusion,when the diameter d of the billet wasΦ30 mm and the flattening width b was 420 mm,the ultimate thickness t that could be extruded was 7 mm.The continuous extrusion experiment of U-shaped copper strip showed that the error between the experimental results and the theoretical torque values was controlled within 10%,which proved the feasibility and accuracy of the theoretical calculation of the limit size.

关 键 词：铜带 连续挤压 SDV 成型载荷 解析法 

分 类 号：TG379[金属学及工艺—金属压力加工]