Undercut on J-groove seam — cover C-77

Defect found during first-article inspection of Cover C-77. The J-groove weld showed undercut at 180 a on sus304; joint gap measured at 1.2 mm against a 1.5 mm maximum.

Root cause: the two-point locating scheme allowed the upper flange to rotate under clamping load, opening the gap on the far side of the groove.

Corrective action: Reduced current to 165 A and re-qualified the WPS.

Disposition: rework and re-inspect. Lesson recorded for drawings using the same locating pattern.