There are two broad classifications of base metal surface finish. These are produced by using either ground rolls or shot blasted rolls. Each of these basic roll surfaces can be modified to some degree so that several classes under each finish are available.
|Shot Blast Roll Finish||5C||A standard shot blast finish for general application of tin mill products. Also referred to as "matte". Average roughness (Ra) aim 30-60.|
|5D||A heavy shot blast finish for special applications. Average roughness (Ra) aim 70-100.|
|Ground Roll Finish||7B||A smooth finish that may contain fine grit lines for special applications. Average roughness (Ra) aim 17.|
|7C||A smooth finish with grit lines. This is the standard finish for tin mill products. Average roughness (Ra) aim 12-22.|