New technology for thick plate welding

Jet transitions in gas shielded welding are widely used in actual welding operations. The jet transition occurs when a large welding current is used and a mixed gas of inert gas or high argon is used. In the late 1980s, the German standard DIN 1910-4 defined the jet transition as follows: "In the jet transition, the wire droplets are transferred into the weld in the form of fine particles, and no short circuit occurs in the droplet transfer. "The voltage of the arc is higher during the jet transition, which means that the arc is longer (see Figure 1). Longer arc stability is reduced, and the arc is easily deflected by the influence of magnetic partial blow, which is prone to weld undercut and pore formation. In addition, the burning loss of the alloy is also serious, which has an adverse effect on the practical application of the jet transition. Hans-Ulrich Pomaska ​​[1], one of the precursors of the fused gas shielded welding, proposed the "short arc jet transition of energy concentration" method. This method reduces the arc voltage of the jet transition a little, with the result that it is impossible to completely avoid the short circuit during the welding process. If the short-circuit duration is short, although the voltage drops sharply, the current does not rise much. In this state, the welding will not splash, but there are some small splashes. The sound heard during welding is a slight squeak, not a confusing noise. Figure 2 shows the current and voltage changes over time in this soldering mode. This arc is quickly applied to the real world. The definition of the corresponding jet transition in the German standard is also changed to read: "The droplet transfer is carried out in the form of fine particles, and there is almost no short circuit in the droplet transfer."

If the arc voltage of the injection transition is further reduced, the time during which the droplet is short-circuited is prolonged, causing severe splashing. Although it is theoretically desirable to reduce the voltage, it has been difficult to apply in practice. With the development of inverter technology and the development of modern digital control systems, ultra-short arc voltage injection transient welding applications have become possible. The new type of welding machine has a fast enough adjustment speed to control the excessive increase of the welding current before the normal arc voltage is reached after the short circuit is disconnected, and also controls the output energy of the welding machine per unit time. This can greatly reduce the spatter generated during the short-circuit transition, so that the ultra-short arc voltage injection transition can be successfully applied in practice. This new form of welding arc, we call it "EWM forceArc--super-arc".

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