Category D weld joints typically involve?

• A. Circumferential Seams
• B. Fillet Welds Only
• C. Longitudinal Seams
• D. Butt Joints in T-junctions

Answer: (C)

Category D weld joints are the long, lengthwise joints that form the main shell seams on cylindrical pressure vessels. When a cylinder is built from plates, the edges are welded along the length to create a seam that runs parallel to the vessel’s axis. This longitudinal seam is the typical representation of Category D joints. Circumferential seams wrap around the shell and are a different orientation, while fillet welds or butt joints at T-junctions describe other connection types rather than the main lengthwise shell seam. So the best fit for Category D is the longitudinal seam.