双电弧集成冷丝复合焊中冷丝位置对焊接过程的影响

Effect of cold wire position on the welding process in twin-arc integrated cold wire hybrid welding

搭建了双电弧集成冷丝复合焊接系统,研究了冷丝不同位置对焊接过程的影响机理,其中包括冷丝作用位置对其加热熔化作用及表面成形的影响.实验结果表明:冷丝从两引导焊丝正前方送入时,熔池前端对冷丝的加热熔化作用不充分,冷丝末端会顶触熔池底部,随着冷丝的持续送进和母材的向后移动,某一时刻冷丝回弹,焊丝末端的熔滴弹出落在母材表面形成大颗粒飞溅.当冷丝从侧面送入时,熔池一侧的温度较低,影响熔池金属的流动,导致最终的焊缝成形不对称分布.当冷丝从两引导焊丝正后方送入熔池时,冷丝始终插入熔池中,焊接过程稳定,是理想的冷丝作用位置.此外,随着冷丝送丝速度的增加,两种脉冲电流模式(同相和反相)下,熔敷率均随之增加,且相差不大.同相脉冲电流下电弧对冷丝的加热熔化作用最强烈,反相脉冲电流下次之,直流模式下最弱.

With rapid social and economic development, high-efficiency welding technology has become an important development direction in the field of welding. In recent years, scholars and professionals in many countries have devoted themselves to further increasing the welding efficiency by improving welding materials, welding process, and arc-welding equipment. The welding efficiency can be increased using two approaches: one is increasing the welding speed, the other is increasing the welding deposition rate.Considering these two methods, typical technologies such as multiwire submerged arc welding(SAW) and multiwire gas metal arc welding(GMAW) were proposed. A twin-arc integrated cold wire hybrid welding system was established. The mechanical effect of the cold wire position on the welding process was studied, including its effects on heating, melting, and weld surface formation. Results show that the melting of cold wire depends on the front end of the weld pool, and the melting effect of the weld pool on the cold wire is not sufficient when the cold wire is fed in front of two leading wires. The end of the cold wire makes contact with the bottom surface of the weld pool with the continuous feeding of the cold wire. Droplets melted at the wire ends are ejected and fall on the base metal surface to generate a globular spatter with the backward motion of the base metal. The thermal distribution on the side of the weld pool decreases as the cold wire is fed inside of the two leading wires. Hence, the flow of molten metal is affected, ultimately leading to an uneven weld formation. The cold wire is stably inserted into the weld pool when fed behind the two leading wires, representing the optimum cold wire position. Moreover, the deposition rates increase with an increase in the cold wire feed speed and show little change under two-pulse phase differences(in-phase and reverse-phase pulse differences). The effect of arc heating and melting on the cold wire was most intense at the in-phase pulse current, followed by the reverse-phase pulse current and subsequently direct current.