The quick answer is NO! Using flux with the GTAW process is not (Key word here) NECESSARY... Nor is it a requirement to use at all times when qualifying a procedure or welders.
The only way it would be necessary to use flux is if the actual job order/ job condition requires you to qualify/ certify the welders to USE a flux... If the contract specs, and access is'nt limited to complete the joint, and the EOR does not REQUIRE you to use flux, then you DO NOT NEED TO USE FLUX when qualifying the procedure or the welders. Hope this helps.
Respectfully,
SSBN727
Run Silent... Run Deep!!!