温差拉伸和随焊激冷配合使用控制焊接变形

对温差拉伸和随焊激冷配合使用控制铝合金薄板焊接变形的联合工艺进行了数值模拟和试验研究。数值分析表明 ,随焊激冷更倾向于在焊缝中心造成显著的纵向塑性拉伸 ,而温差拉伸则倾向于在近缝区造成显著的塑性拉伸。将二者配合使用 ,不仅可以靠温差拉伸将焊缝和近缝区在加热阶段形成的纵向塑性压应变控制在较低的水平 ,还可以靠随焊激冷增加冷却阶段的纵向塑性拉伸进一步抵消焊缝区已经形成的压应变。因而充分发挥二者的作用 ,有效地控制焊件的残余变形。试验研究与数值模拟得到的结论基本一致 ,随焊激冷和温差拉伸联合使用 ,可使 5 4 0mm× 3 0 0mm× 2mm的LY1 2CZ薄板焊后纵向挠曲由单独使用温差拉伸时的 2 .87mm和单独使用随焊激冷时的 4 .88mm降低到 0 .80mm的水平

Using thermal tensioning and trailing intense cooling simultaneously to reduce welding distortion

The technique using thermal tensioning and trailing intense cooling simultaneously to reduce welding distortion was investigated by both numerical simulation and experiments. Numerical simulation shows that trailing intense cooling tends to cause obvious longitudinal plastic tensioning in the weld, while thermal tensioning can create plastie tension in the adjacent zones to the weld. When they are coupled to use the longitudinal plastic compressive strain in the weld and its adjacent zones can be reduced markedly by thermal tensioning in the heating stage and the plastic tensioning following in the cooling stage will be increased by trailing intense cooling. The former takes place more remarkably in the zone adjacent to the weld while the latter in the weld, so the compressive strain will be evenly cancelled out further and the residual distortion of welded piece will be reduced greatly. The same conclusions were drawn from aluminum alloy welding experiments.