A welding machine is a unique tool that, in skilled hands, is able to connect individual elements of metal structures into a single whole with the help of reliable sewing. At the same time, the quality of such a connection, according to professionals, directly depends on the correct choice of current and thickness of the electrodes.
If the above characteristics were not chosen correctly, the welder will certainly encounter electrode “sticking”, metal spattering or burning of the workpiece. Each of these problems significantly reduces the quality of the connecting seam, and their elimination depends on the choice of the intensity of the welding current.
Standard parameters, which are usually indicated by manufacturers on each package of electrodes, do not always work correctly in this case, since the quality of welding depends on the thickness and composition of the metal, working conditions, as well than voltage in the network. Therefore, even professionals sometimes have to select the current strength empirically.
However, beginner welders should first familiarize themselves with the general rules for choosing the thickness of electrodes and welding current when working with metal of different thicknesses, given in the table:
|Metal thickness (mm)||Electrode (mm)||Current (A)|
If you study this table carefully, it becomes clear that ideally there are about 30 A per millimeter of electrode thickness. The problem is that standard parameters are extremely rare. Therefore, welders must adapt to specific conditions, especially with tension problems.
Professionals cope with this task without any problems, and novice welders are advised to first try to put a few seams on a small piece of metal with a suitable composition and thickness, changing the current strength by connection status function:
- With insufficient amperage, almost all of the electrode metal is above the surface of the parts to be welded. In this case, the seam turns out to be convex and does not provide sufficient strength, since the metal at the junction simply does not warm up.
- If the current is too high, the metal will begin to spread over the surface of the part, and small burns may appear on the reverse side. With a significant excess of parameters, burns are also formed from the outside.
- With optimal characteristics, the seam should be slightly vague (in width – no more than 2 electrode diameters) and low (less than 1.5 millimeters), and the metal on the back of the part is completely heated.
In conclusion, some advice for beginner welders: it is recommended to work with thin metal (up to 3 millimeters) in reverse polarity so that the seam is wide and shallow, which eliminates the appearance of burns; the highest current strength is needed when welding corner joints, and the lowest rates are used when “decorating” the bottom joint.