The welding current in medium frequency spot welding machine is the external condition that generates internal heat source – resistance heat. The influence of current on heat generation is greater than that of resistance and time. It affects the heating process of spot welding through the following two ways:
Adjusting the effective value of welding current will significantly change the heat generation of the internal heat source, affecting the heating process. In addition, the waveform characteristics of the current during spot welding also affect the heating effect.
The current field distribution characteristics formed on the internal resistance (average value) of the workpiece by the welding current will make the heating intensity uneven at various locations in the welding area, thereby affecting the heating process of spot welding. The current field and current distribution during spot welding have the following characteristics:
The current lines will concentrate and shrink at the fitting surface of the two workpieces, resulting in concentrated heating effect at the fitting surface.
The current density at the edge of the fitting surface peaks, where the heating intensity is the highest, ensuring the normal growth of the fusion core.
The current field during spot welding is characterized by an uneven heating process, with different temperatures at various points in the welding area, thus producing an uneven temperature field. By selecting different welding current waveforms and changing electrode shapes and end sizes, the current field morphology can be changed and the current density distribution can be controlled to achieve the purpose of controlling the shape and position of the fusion core: leo@agerawelder.com
Post time: Feb-28-2024