Cracks, suckback, undercut, and overlap are discontinuities found in which type of product?

• A. Castings
• B. Forgings
• C. Extrusions
• D. Weldments

Answer: (D)

Discontinuities like cracks, suckback, undercut, and overlap occur in welded joints because welding involves local melting and rapid solidification that can introduce defects at the weld bead and heat-affected zone. Cracks are breaks in the weld metal or HAZ caused by stresses or hydrogen embrittlement. Suckback is a crater-like withdrawal of molten metal as the weld solidifies, leaving a depression at the end of the bead. Undercut is a groove melted into the base metal along the weld toe, reducing cross-section and creating a stress riser. Overlap occurs when excess weld metal flows beyond the edge of the weld without fusing to the base metal. These issues are characteristic of welded constructions (weldments) and are not typically described as defects in castings, forgings, or extrusions, which have different defect profiles.