Influência da variação invertida da tensão e corrente na eficiência térmica do processo de soldagem TIG.

Abstract

The objective of this work was to evaluate the relationship between the energy generated by the arc and the heat absorbed by the base metal, that is, its thermal efficiency (k), if the welding parameters (voltage and current) in the TIG welding process (tungsten inert gas) would vary so that the arc power is maintained the same. A continuous water flow calorimeter was used. With the results of the work it was possible to verify the contribution of each welding parameter (voltage or current) on the thermal efficiency of the process and on the weld bead geometry. It was shown that an increase in arc voltage provokes a growth of the heat generation in the arc but does not necessarily favor the heat transfer to the workpiece (that is, this does not favor the heat input - HI), because the increase of heat will happen in the arc column and will be lost to the environment almost for full. On the other hand, an increase in the current will always lead to an increased generation of heat in the arc and, what is more important, will always favor the transfer of heat to the workpiece (increasing the HI). This happens due to the fact that the increase in current causes a growth of heat in all three zones of the arc, and even with the loss of heat by the column (by the way, the smallest part of the three), the HI will grow because the heat generated in the coupling arc – base metal will be transferred to the workpiece almost in full.