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本文通过试验发现熔化极脉冲焊具有电弧形态可控的特点,通过两种典型目视电弧形态的控制可以在一定程度上控制脉冲电弧的工艺特性。不同的目视电弧形态是不同的瞬时电弧形态的变化过程决定的,本文研究了脉冲电流波形、脉冲电流值和保护气氛等因素对瞬时电弧形态变化过程的影响,为控制电弧形态提供了可能的途径。熔滴过渡与电弧形态有密切的关系。不同的电弧形态决定了不同的熔滴过渡形式(?)本文用高速摄影技术通过平焊和仰焊试验对不同熔滴过渡形式进行了比较,认为一脉冲一滴(脉冲喷滴过渡)和一脉冲多滴(脉冲射流过渡)在平焊和仰焊位置都能实现有力的轴向过渡,但一脉冲多滴的过渡形式可以有更宽的规范区间。跳弧现象是射流过渡的共同物理本质,只有在出现跳弧现象之后,焊丝端头的液体金属才能产生本质的变化,并出现射流过渡的特点。连续电流射流过渡时,跳弧现象只在引弧初期出现一次,而脉冲电流的脉冲射流过渡时,跳弧现象在每次脉冲电流期间都重复出现。脉冲喷滴过渡和脉冲射流过渡时皆有熔滴在脉冲电流停止后过渡的现象。这种在脉冲电流停止后仍能实现熔滴有力过渡的原因是由于惯性作用和细长金属液柱失稳而自动截成数段,形成分离的小熔滴而实现过渡的。
In this paper, it is found that the pulse-pulse welding has the feature of controllable arc shape. The control of the two typical visual arc patterns can control the process characteristics of the pulse arc to a certain extent. Different visual arc shapes are determined by the different process of instantaneous arc shape change. In this paper, the influence of pulse current waveform, pulse current value and protective atmosphere on the morphological change of instantaneous arc is studied. It is possible to control the shape of arc way. Droplet transfer and arc shape are closely related. Different forms of arc determine the different forms of droplet transition (?) In this paper, by high-speed photographic technology by flat welding and welding experiments of different forms of droplet transition were compared, that a pulse of a (pulse droplet transition) and a pulse Many drops (pulsed jet transitions) can achieve a strong axial transition both in the flat and in the stand-off positions, but a more gradual specification range can be achieved for a one-pulse, multi-drop transition. The phenomenon of jump arc is the common physical essence of the jet transition. Only after the phenomenon of jump arc occurs, can the liquid metal at the tip of the wire produce the essential change, and the characteristics of jet transition appear. When the continuous current jet transitions, the arc jump phenomenon occurs only once in the initial stage of arc initiation. When the pulse current of the pulse current transitions, the arc jump phenomenon occurs repeatedly during each pulse current. Pulse drop transition and pulse jet transition when there is a drop in the pulse current transition after the stop phenomenon. The reason that this kind of droplet can still transition after the impulse current is stopped is because the inertia and the instability of the elongated metal liquid column automatically cut into several sections to form the separated small droplet to realize the transition.