摘要
目的采用焊接中施加冷热源辅助的方式对焊接应力进行控制,以减小焊后残余应力。方法采用热机耦合数值模拟的方式对2024铝合金搅拌摩擦焊接过程进行仿真,研究采用焊缝两侧加热且底部激冷的温差拉伸辅助工艺降低残余应力的效果。结果与常规工艺相比,温差拉伸时焊缝附近区域的温度梯度明显减小,焊缝区域温度峰值降低了75.3℃;搅拌头后方形成一个焊缝两侧温度高中间温度低的马鞍形温度场。两种工艺下的纵向残余应力峰值均位于焊缝边缘;相比于常规工艺,温差拉伸工艺下的残余应力峰值降低了23.4%。结论冷热源辅助可以有效减小搅拌摩擦焊接头的残余应力峰值。
The work aims to control the welding stress by applying cold and thermal sources during the welding process,so as to reduce the residual stress after welding.The friction stir welding of 2024 aluminum alloy was simulated by thermo-mechanical coupling numerical simulation,and the effect of thermal tension process for heating at both sides of weld and chilling at the bottom to reduce residual stress was studied.Compared with the conventional process,the temperature gradient in the area near the weld was obviously reduced during thermal tension process,and the temperature peak value in the weld area was reduced by 75.3℃.A saddle-shaped temperature field with high temperature on both sides of the weld and low temperature in the middle was formed behind the rotating tool.The peak value of longitudinal residual stress under both processes was located at the edge of weld.Compared with the conventional process,the peak residual stress value was reduced by 23.4%under thermal tension process.Cold and thermal sources can effectively reduce the peak value of residual stress in friction stir welding joints.
作者
史学海
吕赞
胡云瑞
王留芳
SHI Xue-hai;LYU Zan;HU Yun-rui;WANG Liu-fang(CSR Qingdao Sifang Locomotive and Rolling Stock Co.,Ltd.,Qingdao 266111,China;Shenyang Aerospace University,Shenyang 110136,China)
出处
《精密成形工程》
2020年第2期55-60,共6页
Journal of Netshape Forming Engineering
基金
国家自然科学基金(51705339)。
关键词
搅拌摩擦焊
温差拉伸
温度场
应力场
friction stir welding
thermal tension
temperature fields
stress fields
