空心钨极同轴填丝焊空间热场分布特征

Spatial thermal field distribution characteristics of hollow tungsten arc welding with coaxial filler wire

利用理论建模与试验相结合的方法,系统研究了空心钨极同轴送丝焊接过程中焊丝熔化热量的来源.结果表明,基于磁流体力学的理论模型分析结果和实际情况高度吻合;在高温电弧热辐射及钨极热传导共同作用下,钨极内孔形成的梯度式高温区会对焊丝起到一定的预热作用;环状空心钨极电弧中轴线上近几何中心区域的温度最高,焊接电流400 A时温度高达13 700 K;熔滴与液态熔池接触后电势相等,在最小电压原理作用下,部分高温电弧的阳极作用区会由液态熔池转变至焊丝表面,同时部分焊接电流会从焊丝流过,形成的电阻热也是高效熔丝的主要原因之一;熔滴过渡分析结果表明空心钨极同轴填丝焊接具有较高的工艺稳定性,是一种极具发展前景的焊接新方法.

The source of welding wire melting heat in the process of hollow tungsten arc welding with coaxial wire feeding is systematically studied by using the method of theoretical modeling and experiment. The results show that the analysis results of the theoretical model based on magnetohydrodynamics are highly consistent with the actual situation. Under the combined action of high temperature arc heat radiation and cathode heat conduction, the gradient temperature zone formed in the inner hole of cathode will preheat the welding wire to a certain extent. The temperature near the geometric center on the central axis of annular hollow tungsten arc is the highest,and the temperature is up to 13 700 K, when the welding current is 400 A. The potential is equal after the droplet contacts with the liquid molten pool. Under the action of the principle of minimum voltage, the anode action area of some high-temperature arc will change from the liquid molten pool to the surface of the welding wire. At the same time, some welding current will flow through the welding wire, and the resistance heat formed is one of the main reasons for the high-efficiency fuse.The results of droplet transfer characteristics analysis show that hollow tungsten arc welding with coaxial filler wire has high process stability and is a new welding method with great development prospect.