固定短芯棒拔管残余应力分布规律研究

为了研究固定短芯棒拔管残余应力的产生机理和分布规律,采用弹塑性有限元法模拟拉拔过程,讨论模具形状参数、拉拔变形参数、摩擦条件对残余应力的影响.结果表明,当模具半锥角α较小时,随着α的增加,残余应力增大;在减径率εs一定的条件下,随着减壁量ΔS的增加,钢管内外表面的残余应力逐渐减小,在ΔS一定而εs增加时,内外表面上残余应力呈先增大后减小变化趋势;同时,轴向残余应力随着拉拔速度v和摩擦系数μ的增加而增大.

Study of residual stress in pipe drawing process with fixed mandrel

To study the mechanism of production and regularities of distribution for residual stress in pipe drawing with fixed mandrel,the drawing process was investigated by elastic-plastic FEM.Meanwhile,influencing factors to residual stress,including the shape of die,the deformation parameters and the condition of friction,were discussed.The results show that when semi-die angle α is not so large,the residual stress increases with the increase of α;for a given diameter reduction ratio εs,residual stress in outer surface decreases with the increase of wall thickness reduction ratio ΔS,and for a given ΔS,with the increase of εs,residual stress in both surfaces increases firstly and then decreases;the larger are the value of drawing speed vand friction coefficient μ,the larger is the axial residual stress.