管坯镦挤成形工艺成形极限的上限法分析  

Upper-bound analysis of forming limit of tube upsetting process

作　　者：丁泰然 胡成亮 赵震 龚爱军 施卫兵 DING Tai-ran;HU Cheng-liang;ZHAO Zhen;GONG Ai-jun;SHI Wei-bing(National Engineering Research Center of Die&Mold CAD,Institute of Forming Technology and Equipment,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200030,China;Jiangsu Sunway Precision Forging Co.,Ltd.,Dafeng 224100,China)

机构地区：[1]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模具CAD国家工程研究中心,上海200030 [2]江苏森威精锻有限公司,江苏大丰224100

出　　处：《塑性工程学报》2019年第4期28-33,共6页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(51475294)

摘　　要：根据管坯中部镦挤成形特点,考虑到成形过程中内壁会形成凹陷、折叠等缺陷,建立了带凹陷的平行速度场。求解了各个区域的应变速率分量以及等效应变速率,并且计算了各个区域的塑性变形功率消耗、速度间断面上剪切功率消耗与接触面上摩擦功率消耗,从而获得了变形总功率和单位变形力;借助上限法对管坯镦挤成形过程进行解析,分析了凹陷对单位变形力的影响,推导出了凹陷判别式;结合实际工艺条件,绘制出管坯镦挤的成形极限图,获得了相应的工艺安全区和危险区,并在此基础上探讨了相对法兰外径、坯料内外径比、相对法兰高度等对成形极限的影响。According to the forming characteristics of upsetting in the middle of tube billet,the parallel velocity field with cavity was es-tablished considering the defects of inner wall such as cavitation and folding.The strain rate components and equivalent strain rate of each region were solved,and the plastic deformation power consumption,the shear power consumption on the velocity discontinuity and the fric-tion power consumption on the contact surface of each region were calculated,then the total deformation power and the unit deformation force were obtained.The upsetting process of tube billet was analyzed with the upper-bound method,the effect of cavity on unit deforma-tion force was analyzed,and the cavity discriminant was deduced.Combined with the actual process conditions,the forming limit diagram of tube billet upsetting was drawn,and the corresponding process safety zone and danger zone were obtained.On this basis,the effects of relative flange diameter,blank inside and outside diameter ratio and relative flange height on the forming limit were discussed.

关 键 词：管坯镦挤成形 上限法 缺陷分析 成形极限 

分 类 号：TG376[金属学及工艺—金属压力加工]