钛合金薄板带热沉钨极氩弧焊的应变场

Strain Field of Gas Tungsten Arc Welding with a Spot Heat Sink on Titanium Alloy Thin Plate

采用数值模拟和试验相结合的方法对比研究了钛合金常规钨极氩弧焊(GTAW)及带热沉的钨极氩弧焊,即动态控制低应力无变形(DC-LSND)GTAW焊接过程中纵向应变场的形态与发展历史。DC-LSNDGTAW焊接过程中,由于紧随热源之后热沉冷却介质的急冷作用,使得热沉作用部位产生强烈收缩,热源与热沉之间的极大温度梯度,对高温金属产生较强的拉伸作用,使得焊缝中拉伸塑性应变增大,近缝区压缩塑性应变减小,焊缝与近缝区的不协调应变减小。DC-LSND焊时,不但可以降低残余应变,减小变形;而且,在所选用的焊接条件下,DC-LSNDGTAW焊缝中甚至还可获得拉伸的不协调应变。

The longitudinal strain field pattern and the longitudinal strain developing history were studied numerically and experimentally for both the conventional Gas Tungsten Arc Welding (GTAW) and Dynamically Controlled Low Stress No-Distortion (DC-LSND) GTAW welding of a titanium alloy. Results show that high tensile effect generated by heat sink with sharp cooling and contraction of weld metals is acting in the zone between the arc and the trailing heat sink during DC-LSND GTAW welding, which increase tensile plastic strain of weld and decrease compress plastic strain in the zone near to the weld. All of these phenomena mitigate the incompatible strain in the weld and the zone nearby. With the selected welding parameters, residual tensile incompatible strain can be reached in the weld during DC-LSND GTAW -welding.