Generally socket-welded pipe is not used for nominal pipe sizes above:

Generally socket-welded pipe is not used for nominal pipe sizes above:

• A. 3 inches
• B. 4 inches
• C. 1 inch
• D. 2 inches

Answer: (D)

Socket welds are practical for small-bore piping because the pipe ends fit into a recessed socket and can be joined with a relatively simple fillet weld, offering quick assembly and adequate strength at low diameters. However, as pipe diameter grows, the socket geometry becomes more awkward to weld around the full circumference, increasing heat input, distortion, and the risk of leakage at the root. The weld root can be harder to achieve reliably on larger bore joints, and the resulting stress concentration at the inner weld area becomes more significant under pressure and temperature. For these reasons, full-penetration butt-weld joints are preferred for larger diameters, while socket welds remain generally limited to nominal pipe sizes up to two inches.

Socket welds are practical for small-bore piping because the pipe ends fit into a recessed socket and can be joined with a relatively simple fillet weld, offering quick assembly and adequate strength at low diameters. However, as pipe diameter grows, the socket geometry becomes more awkward to weld around the full circumference, increasing heat input, distortion, and the risk of leakage at the root. The weld root can be harder to achieve reliably on larger bore joints, and the resulting stress concentration at the inner weld area becomes more significant under pressure and temperature. For these reasons, full-penetration butt-weld joints are preferred for larger diameters, while socket welds remain generally limited to nominal pipe sizes up to two inches.