相对厚度对锥形零件拉深成形的影响  

Effect of Relative Thickness on Tapered Part Drawing

作　　者：任运来[1] 吕亚臣[1] 彭加耕[1] 朱磊[1] 

机构地区：[1]燕山大学机械工程学院,秦皇岛066004

出　　处：《机械工程学报》2010年第8期51-55,共5页Journal of Mechanical Engineering

基　　金：国家科技支撑资助项目(2007BAF02B07-5)

摘　　要：分析计算锥形零件拉深成形中侧壁上各质点的悬空位移与周向应变,结果表明:初始位于凹模口处的材料环有最大的悬空位移与周向应变,拉深成形中此处材料首先产生压缩失稳。为避开锥形零件拉深成形计算中力学方面的困难而又抓住其实质,在凹模口处切取材料环并定义为锥形零件拉深的关键环。拉深成形中,关键环有周向压缩和周向压缩失稳两种可能的变形方式,变形方式的选择受锥形零件尺寸、板厚及材料物理性能的制约,仅产生周向压缩变形的称为厚壁锥形零件,否则称为薄壁锥形零件。通过比较压缩变形载荷与压缩失稳变形载荷的大小,导出了临界相对厚度。分析临界相对厚度的表达式可知,瞬时屈服应力与塑性模量是影响临界相对厚度的主要因素,借助临界相对厚度得到了区分厚壁锥形零件与薄壁锥形零件的条件。试验表明:理论计算与试验结果相差不大。The displacement and circumferential strain of particles on the sidewall which does not lean against die wall during tapered part drawing are analyzed.The result indicates that materials located in the orifice of the concave die at the beginning have the largest displacement and circumferential strain.The compression buckling deformation takes place first at here during tapered part drawing.To overcome the mechanical difficulty in calculating tapered part drawing and seize its essence,a material ring is cut at the orifice and defined as key ring during drawing.The key ring has two possible deformation modes,i.e.circumferential compression and circumferential compression buckling during drawing.The choice of deformation mode is restricted by tapered part size,sheet thickness and physical properties of material.The part only having circumferential compression deformation is called thick-wall tapered part,otherwise called thin-wall tapered part.By comparing the load of compression deformation and that of compression buckling deformation,the critical relative thickness is derived.It can be seen from the analysis of the expression that the instantaneous yield stress and plastic modulus are the main factors of influencing the critical relative thickness.The condition for distinguishing thick-wall tapered part from thin-wall one is obtained by means of the critical relative thickness.Experiment shows that the difference between theoretical calculation and experimental result is not great.

关 键 词：锥形零件 拉深成形 冲压 塑性变形 材料加工 

分 类 号：TG316[金属学及工艺—金属压力加工]