S9074-AQ-GIB-010/248 Rev 1
f. A decrease greater than 10 percent or 5 cubic feet per hour (whichever is larger) in the rate of gas flow below that used during qualification for torch shielding gases only. g. The addition or deletion of a shielding gas. h. Elimination of purge gas, except that purge gas may be deleted as follows (for S-51, S-52, S-53, and S-53A materials, see 4-7.7.l below): (1) Welds re-welded from the reverse side. (2) Partial penetration and fillet welds and groove welds made with backing strips or rings. (3) Socket welds, unless qualification was performed with socket weld joints and purging was employed. i. For plasma arc keyhole welding, a change in the nominal composition of the backing (i.e., purge) gas or gas mixture. j. See footnote 8 of table 7-2. k. For S-51, S-52, S-53, and S-53A materials, a change from welding in a chamber to welding outside of a chamber. l. For S-51, S-52, S-53, and S-53A materials welded outside of a chamber, the omission of a trailing shield or backing (purge) gas. m. For S-51, S-52, S-53, and S-53A materials, the requirements of a., b., d., e., and f. also apply to trailing shield gas. Also, addition of a trailing shield gas other than a gas of the same composition as the torch shielding gas. 4-7.8 HEAT TREATMENT. a. A decrease in preheat or interpass temperature below the minimum temperature specified by the applicable fabrication document. For stud welding, also a decrease in minimum preheat temperature greater than 100 °F. b. An increase in preheat or interpass temperature above either: (1) The maximum interpass temperature specified by the applicable fabrication document, except for S-1 materials without toughness requirements, or (2) Where no maximum interpass temperature is specified by the fabrication document, the maximum interpass temperature used for qualification. c. The addition or omission of post-weld heat treatment; for S-1 materials, addition or omission of stress relief heat treatment does not require requalification, unless required by 4-7.8.e below. d. A change in PWHT outside the temperature range specified in the applicable fabrication document for the materials involved. e. For base metals and weld metals having impact requirements, a change in the PWHT temperature and time range from that recorded in the procedure qualification record. The procedure qualification test weldment shall be subjected to heat treatment essentially equivalent to that encountered during fabrication of the weldments, including at least 80 percent of the aggregate times at temperature. A change in temperature that is within the range specified by the fabrication document does not require requalification. f. For S-44 materials, the addition or omission of a post-weld solution anneal. Also, an increase greater than 25 percent in the total stress relief holding time beyond that used for qualification.
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