Welding Thoughts (Relationship of Current and Arc Temperature)

[Grayfox]

Common Temperature ranges from a welding arc can range from 3000-8000 Degrees Celsius. I would like to know the direct relationship of a resultant arc temperature based on the amount of current (amps) flowing. Let's say common steel for the base metal (Electrical Resistivity: 1.74e-005 ohm-cm). One can adjust the amps from a welder to say 125, but I'm not sure how other variables such as properties of the electrode (mig wire resistivity, diameter), length of the arc, or even reverse polarity (we'll assume straight polarity) affect this value. My guess is that if the electrode (welding gun wire) is +, more heat is generated at the electrode, and if the base metal is +, a larger portion of the energy is distributed to the base metal. Of course we'll neglect any heat transfer with the shielding gas or ambient air. Getting past all that, would we apply something like Power=I^2*R or Q=mcdt?

 

[anorlunda]

The temperature at the tip is pretty independent of the current. But it is sensitive to the surrounding gas, and the rod composition and shape.

But the temperature away from the tip does depend on current, and geometry, air flow, and other factors.

The following paper, talks about ways to consider all those things to calculate temperatures at different point within the weld.

https://www.sciencedirect.com/science/article/abs/pii/S135943111931350X