All weld procedures are to be approved by Quality Assurance Manager
All general repair and modification welding is to be done by Gas Metal Arc Welding (GMAW) (or MIG) method only unless prior approval has been given.
All seating surface overlay welding is to be done by Gas Tungsten Arc Welding (GTAW) (or TIG) method only unless prior approval has been given.
When applying overlays that require preheat are applied to P # 8 base materials the preheat temperature applied should be as minimal as practical.
All welds shall have dye-penetrant examination performed on them during the process as necessary and after final finishing of the part.
* (Per ANSI B31.3) Recommended Preheat
1 (Per ANSI B31.3) 1100-1200°F for nominal thickness > ¾” and no PWHT for nominal thickness < ¾”.
2 (Per ANSI B31.3) 1300-1375°F for nominal thickness > ½” and no PWHT for nominal thickness < ½”.
3 (Per ANSI B31.3) 1300-1400°F for nominal thickness > ½” and no PWHT for nominal thickness < ½”.
4 (Per ANSI B31.3) 1350-1450°F for all thickness.
5 15 minute minimum holding time
6 (Per ASTM A182) Recommended Preheat and Interpass Temperature Range
(Note: Some of these values conflict with ANSI/ASME B31.3 values)
7 (Per ASTM A182) 1900°F PWHT + WQ with no holding time given
(per paragraph 12.1.5 “... may be (welded) without (PWHT)...”)
8 Listed as A5.9/28 because these classifications are in the process of being added to AWS A 5.28 and deleted from AWS A 5.9
Source: qualichek.com
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