摩擦对工件间推挤式等通道转角挤压技术的影响  

Effect of Friction on Pushing Type Equal Channel Angular Pressing Technology for Workpieces

作　　者：成城[1] 许晓静[1] 费震旦[1] 蒋凌[1] 罗勇[1] 

机构地区：[1]江苏大学先进成形所,江苏镇江212013

出　　处：《热加工工艺》2012年第15期78-82,85,共6页Hot Working Technology

基　　金：江苏省高校科研成果产业化推进项目(JH10-37);江苏大学拔尖人才培养工程基金项目(1211110001)

摘　　要：运用有限元软件DEFRORM-3D对工件间推挤式等通道转角挤压(ECAP)技术进行了仿真模拟和试验研究(所用模具拐角为100°),重点分析了推挤变形过程及摩擦系数(μ)的影响、推挤接触区形貌与应变特征以及μ对最大挤压载荷、工件平均有效应变及加工单位体积工件产生单位有效应变所消耗的能量的影响。模拟结果表明,工件间推挤式ECAP加工与单根工件ECAP加工有很大不同。在该模拟条件下,μ≥0.7时,推挤式ECAP加工不能进行。工件推挤接触区形貌及接触面积在μ<0.5时,随着μ的增大,接触区形貌发生变化、接触面积增大,而当μ>0.5后,基本不发生变化。当μ≥0.5后,工件接触两端呈典型剪切变形特征,与单根工件ECAP加工有本质不同。工件接触区应变在μ=0.5时均匀性最佳,并与工件其他区域应变大小相差很小。最大挤压载荷随着μ增加而增大的幅度比传统ECAP更为强烈。工件的平均有效应变比单根工件ECAP加工的应变有所增加。工件间推挤式ECAP加工单位体积工件产生单位应变所消耗的能量随着μ的增大而增大。试验研究表明,当μ过大时推挤式ECAP加工不能进行,而当μ较低时可以实现推挤式ECAP加工,仿真模拟结果与试验结果吻合。The finite element simulation using Deform-3D software and the experimental investigation of workpieces pushing type equal channel angular pressing （ECAP）were carried out. With the special focus on the workpieces pushing deformation process and its dependence on friction between workpieces and ECAP die, the workpieces contacting zone shape and strain features, as well as the friction effect on the maximum pressing load, average effective strain and energy consumption of the unit volume unit effective strain were investigated. The simulation results show that the present ECAP processing procedure has considerable differences from one workpiece ECAP processing procedure. As friction coefficients are large, such as above 0.7, the present ECAP processing procedure can＇t be realized. With the increase of friction coefficient up to 0.5, the shape of workpieces contacting zone change and its area increases. As friction coefficients are not less than 0.5, the contacting zone of workpieces keeps almost unchanged, and the ends of workpieces exhibits essentially different features from those of one workpiece ECAP process, which are characterized by typical shear shape, superior strain uniformity and strain magnitude closing to those of workpieces＇ other zones, especially as friction coefficients is 0.5. With the increase of friction coefficient, the maximum pressing loads increases more rapidly than those of one workpiece ECAP technology. The average effective strain of the workpieces pushing type ECAP increases slightly with the growth of friction coefficient. The energy consumption of the unit volume unit effective strain increases enormously. The experiment demonstrates that the workpieces pushing type ECAP process can be realized only on low friction. The simulation and the experiment results were in accordance.

关 键 词：ECAP 工件间推挤式 仿真模拟 

分 类 号：TG376[金属学及工艺—金属压力加工]