Below is a list of Cold Rolled Steel manufacturers from Stockton, California. Cold rolled steel is steel that has been shaped by rolling equipment without the application of heat. A metal roller is a metal forming machine that uses a series of rollers to shape or impart physical qualities onto a metal. When a sheet of metal is passed between two rollers, strain hardening, or the plastic deformation of the material, causes the material to become flattened somewhat. This flattening without heat gives the steel higher levels of strength.