Here is the welding result. Welded a profile pipe 1.5 mm with a gap of 2 mm with electrodes three-3 mm. Cooked without additives with the second electrode, there are no burn-throughs and slagging. Now, in order, I will tell you the technique of welding thin metal, which I often use.
I took a professional pipe 30 by 30 1.5 mm thick. To complicate the task, I washed it down with a grinder with a 2 mm thick disc, as if we were going to weld the connection with a gap.
First, a little theory.
We will weld with a separation with a double poke - this is the whole trick. The direction of welding is angle forward, so the depth of penetration of the metal is less. The polarity is straight-minus to the grip with the electrode, although this contradicts theory, but some advised to try, I compared it on graph paper, the minus on the electrode burns less, now I adhere to this rule with thin metals.
We light the arc, lengthen it a little and abruptly return to the weld pool until the coating touches the metal electrode. And so we do point by point. We do not just cook with a gap, no, but we do exactly these actions - they ignited, lengthened the arc and came back abruptly. See what happens from such an action.
For example, a turning flap wheel. Here we have a weld pool. As soon as we removed the arc, the slag crust immediately envelops the metal of the bath. When re-ignited, it takes some time to melt and disperse this slag crust and get to the metal so that the seam continues to form. During this time, the metal can get too hot and fail, resulting in burn-through.
With a sharp shortening of the arc, we disperse the slag to the sides, and after tearing off, the layer turns out to be thin and re-ignition takes less time, which means that the welding speed increases and the likelihood of burn through. Slagging will also not occur during such welding.
We start welding. The current is about 80 amperes, the electrodes are 3 mm ANO-21, although the manufacturer is ESB, good electrodes. And so point by point without tension that we will burn through and weld our gap.
Brewed up, beat off the slag, there are no burn-throughs and slag in the seam. The result is good.
Friends who are interested in this method, I shot a detailed video of the whole process, because words cannot describe all the small details, take a look.