During the rolling of an ingot, a lamination can result if it contains

• A. Inclusions.
• B. Seams.
• C. Glass.
• D. Arc Strikes.

Answer: (A)

Lamination in a rolled ingot occurs along planes of weakness created by nonmetallic inclusions. These inclusions—oxide, sulfide, or other impurities trapped in the metal—don’t bond as well as the surrounding material. When the ingot is deformed, the metal flows around these rigid particles, and the inclusions can align with the rolling direction to form a continuous plane that splits under stress, producing a laminated structure. Seams are casting-related features that don’t produce the same internal lamination, and surface defects like arc strikes or glass inclusions don’t create the characteristic laminated cross-section the way dispersed inclusions do. Keeping the melt clean and reducing inclusions minimizes this risk.