Rolling Defects

There are two types of rolling defects—surface defects and internal defects as shown in Figures 21.3 and 21.4, respectively.

Figure 21.3 Surface Rolling Defects

Figure 21.4 Internal Rolling Defects

• Surface defects: scale, rust, scratches, cracks, pits, and gouges.
• Internal structural defects: wavy edges, crack in the centre of the sheet (zipper cracks), edge cracks, folds, etc.