局部加载拉应力对平板焊接残余应力场的影响

Influence of loading of tensile stress on welding residual stress field in plate structure

采用有限元模拟技术,观察在局部加载条件下平板焊接残余应力场的应力分布,比较平板构件焊接过程中拉伸与焊后拉伸在降低应力方面的不同效果。发现在局部加载条件下焊接过程中拉伸比焊后拉伸可更好地减小焊接残余应力,且当外加载荷低于材料的屈服强度时,载荷越大,残余应力的降低越明显。用200MPa外截拉伸时,焊后拉伸残余应力最大值由常规焊条件下的235MPa降至130MPa,焊接过程中拉伸残余应力最大值可降至50MPa。结果表明,通过局部加载减小焊接残余应力是可行的。

By finite element method (FEM), the distribution of welding residual stress field in the plate structure was investigated under the condition of local loading, and compared the results of reducing stress between tension in process of welding and after welding. It is found that under the condition of local loading, tension in welding process can decrease the residual stress more significantly than that after welding. When the local loading was lower than the yield strength of the material, the decrease of residual stress become more prominence as the local loading increasing. When 200 MPa loading was applied, the maximum tension residual stresses decreases to 130 MPa after welding and to 50 MPa during welding. These results indicate that the decrease of welding residual stress by local loading is feasible.