If ESO is increased while welding at the same current, what happens to the deposition rate and why?

If ESO is increased while welding at the same current, what happens to the deposition rate and why?

• A. Deposition rate increases due to preheating of the wire
• B. Deposition rate decreases due to longer transfer distance
• C. Deposition rate remains the same
• D. Deposition rate becomes zero

Answer: (A)

Increasing ESO means more resistance heating of the filler wire as it travels to the arc. With the welding current held constant, that additional resistance heat preheats the wire before it reaches the arc, so the wire melts more readily when it enters the weld pool. As a result, more filler metal can be deposited per unit time, raising the deposition rate. If ESO is increased too much, arc stability can suffer, but under moderate increases the preheating effect is the dominant reason deposition rises.

Increasing ESO means more resistance heating of the filler wire as it travels to the arc. With the welding current held constant, that additional resistance heat preheats the wire before it reaches the arc, so the wire melts more readily when it enters the weld pool. As a result, more filler metal can be deposited per unit time, raising the deposition rate. If ESO is increased too much, arc stability can suffer, but under moderate increases the preheating effect is the dominant reason deposition rises.