摘要
采用热弹塑性有限元法对焊缝与母材线膨胀系数匹配对焊接过程中的动态应力以及残余应力的影响规律进行研究。在相同焊接热源模型和热输入量作用下的计算结果表明，焊缝与母材等胀匹配时，焊缝中心的纵向残余应力σx为拉应力。其值随母材屈服强度变化。较低时，焊缝中心σx能达到；而较高时，焊缝中心σx明显低于。当焊缝与母材低胀匹配时（αw＜αP），焊缝中心σx值低于，且随αw的减小而减小，并有可能由残余拉应力转变为压应力；而当焊缝与母材高胀匹配时（αw＞αP），焊缝中心σx值还与焊缝应变硬化指标Hw'有关，Hw'较低时，焊缝中心σx值在达到后不再升高，Hw'较高时，焊缝中心σx值可超过。
The transient and then residual stress in welded joints with thermal expansion coefficient (simply TEC) mis-matching between the weld metal and the parent metal are investigated by using the method of thermal elasto-plastic finite element analysis in this paper. Results of the computation under the same welding heat source show that, longitudinal residual stress σx located in the weld center changes with the yield stress σs of the parent metal under the TEC even matched joints, the residual stress σx is close to equal to the stress σ when the stress σis low,and is abviously lower than the stress σ when the stress σ is high. Besides, the stress σx is lower than the stress σ and drops with the TEC of the weld metal decreasing, and the residual tensile stress σx possibly transverses into the compressive in the TEC undermatched joints. However,the stress σx in the weld center also changes with the strain hardening exponent Hs of the weld metal in the TEC over matched joints. The residual stress σx in the weld center attained as high as σ increases little when Hw' is low,but is somewhat higher than σwhen Hw' is high. The above conclusions are important to design or elect weld e1ectrodes.
出处
《中国机械工程》
EI
CAS
CSCD
北大核心
1998年第2期74-77,共4页
China Mechanical Engineering
基金
国家教委博士点基金!9369902
关键词
线膨胀系数
匹配
残余应力
有限元
焊接
焊缝
thermal expansion coefficient mis-matching residual stress FEM welding
