What is it?

This galvanize defect looks like lines of coatings that show up as dots in the rolling direction of the steel. It is also known as rough surface and beaded surface. It is caused when grooves that are designed into the galvanizing pot sink, build up with zinc, and deposit it or an impression of its buildup, onto the partially-solidified zinc layer on the coil. These lines are usually 1-1.5 inches apart and are usually segregated towards the middle portion of the coil’s width. This defect can also appear as pimpled areas.

Sink Roll Marks