Difference between Black mild steel and bright mild steel?

Answer 1

from what i can gather, which isn't alot:

Cold Rolled Steel Strip is produced, as the term suggests by the further rolling of strip produced by the hot strip mills.Prior to cold rolling, the mill scale has to be removed, normally by the Pickling Process which uses mechanical manipulation (around small diameter rolls) and acid to dissolve the surface scale. The surface is then washed to remove the acid and a light oil added to prevent rusting.

Mild steel sheet is manufactured generally in two grades, cold rolled and hot rolled.

Hot rolled mild steel sheet is the initial product produced by the steel mill as a downstream process prior to further processing such as cold rolling.

Hot rolled mild steel sheet has a mill scale which is usually black in colour. Hence the common name Black Mild Steel Sheet. Black mild steel sheet is commonly used in fabrication shops, it is more economical than cold rolled mild steel sheet.

Black mild steel sheet will usually require more preparation work prior to any finishing system being applied.

Cold rolling is done to:

Reduce the thickness

Improve the surface finish

Improve the thickness tolerances

To offer a range of "tempers"As a preparation for surface coating