Constant voltage is NOT used for which of the following welding processes? A. Gas metal arc welding

B. Flux core arc welding

C. Gas tungsten arc welding

D. Submerged arc welding

It should be noted that Constant voltage is not used for the Gas tungsten arc welding.

Constant voltage can be regarded as the ability to fluctuate output current ,so that in this process set voltage can be maintained. and it is used where the workpieces do not have flat surfaces.

Constant voltage can be used for applications  such as welding process like;

Therefore, option C is correct because Constant voltage is not used for the

Gas tungsten arc welding.

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C. Gas tungsten arc welding

Explanation:

Arc welding processes that employ a continuous fed wire electrode uses a constant voltage power source. This type of power source has a flat volt-ampere curve. The welding current and the electrode feed rate are matched to rate of wire melting and transfer across the arc into the weld pool. A monitoring system is responsible for controlling electrode speed using the arc voltage.