【摘要】 采用切条应力释放法测量钛合金TC4薄板对接试件选用不同的热沉位置分别进行动态控制低应力无变形(DC LSND ,dynamicallycontrolledlowstressno distortion)钨极氩弧焊 (TIG)时试件中的纵向残余应力和纵向残余塑性应变的分布。测量结果表明 ,热源与热沉之间的距离是重要的工艺参数之一 ,该参数对焊接应力和变形的控制效果有很大影响 ,适当的热沉位置是动态控制低应力无变形钨极氩弧焊实现低应力无变形焊接效果的一个必要条件。热源与热沉之间的高温金属处于力学熔化状态、无力学抗力时 ,热源与热沉之间距离的增加有助于降低焊接残余应力 ,减小纵向塑性变形。在所选用的焊接条件下 ,动态控制低应力无变形钨极氩弧焊焊接时热源与热沉相距 3 0mm ,近缝区的不协调应变较小 ,控制焊接应力与变形的效果较好。更多还原

【Abstract】 The distributions of longitudinal residual stress and longitudinal residual plastic strain of Titanium alloy TC4 thin plate were studied experimentally using“cutting-slot stress relaxation”method when the specimens were welded by dynamically controlled low stress no-distortion (DC-LSND) tungsten inert gas (TIG) welding with different positions of heat sink. The experimental results showed that the distance between arc and heat sink is one of important parameters, which can strongly influence the controlling results of welding stress and distortion of TC4 thin plate. Suitable position of heat sink is a necessary factor to reach low stress and no distortion for specimen welded by dynamically controlled low stress no-distortion tungsten inert gas welding. If the high temperature zone between arc and heat sink is in a state of zero stress (called mechanical melting), the increment of the distance between arc and heat sink will be benefit to reduce the welding residual stress and plastic strain of TC4 thin plate. In selected welding conditions, incompatible strain of the zone near the weld is smaller when the specimen is welded by dynamically controlled low stress no-distortion tungsten inert gas welding with 30mm distance between arc and heat sink, and the result to control welding stress and distortion is better.更多还原