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弧焊快速成型中电弧形态及熔滴过渡行为对焊接过程的稳定性和构件成型性有较大影响。对平特性焊接电源单道叠层堆焊时的电弧形态及熔滴过渡行为的变化,建立了MIG单道叠层堆焊实验系统,并利用高速摄像采集了第一层和叠层焊接时的电弧形态和熔滴过渡行为,分析了叠层焊接时电弧长度较第一层的电弧长度出现明显缩短的原因,解释了叠层焊接过程中熔滴过渡比第一层焊接时困难的机理。结果表明:叠层焊接时电弧缩短是因为电弧形态变化使电弧特性曲线发生变化,所以不会出现电弧自调节现象,而干伸长增加,干伸长分压变大,其共同作用导致弧压变小。叠层焊接时电流的减小,导致电弧总机械力减小,使熔滴过渡频率下降,熔滴尺寸增大。
Arc shape and droplet transfer behavior during rapid prototyping of arc welding have a great influence on the stability of welding process and component formability. Aiming at the change of arc shape and droplet transition behavior during flat welding of flat welding power source, a MIG tunneling and surfacing experiment system was established. The first layer and the second layer Arc shape and droplet transfer behavior were analyzed. The reason why the arc length of the first layer was shorter than that of the first layer during lamination welding was analyzed, and the mechanism of the difficulty in welding during the lamella welding was explained. The results show that the arc shortening is caused by the change of arc shape due to the change of arc characteristic curve, so arc self-adjusting phenomenon will not occur, while the dry elongation increases and the dry elongation partial pressure increases. Smaller The current in the stack welding decreases, resulting in the total arc electric force decreases, the droplet transition frequency decreases, droplet size increases.