COATED STEEL MATERIAL AND ITS MANUFACTURE

摘要

PURPOSE:To obtain a coated steel material not requiring pretreatment such as film removal before working or plating by cold working a steel material wetted with a lubricant contg. phosphorus so that the surface of the worked article is coated with a layer contg. phosphorus. CONSTITUTION:A steel material wetted with a liq. lubricant contg. phosphorus is cold worked by extrusion or other process so that the surface of the worked article is coated with a layer contg. phosphorus. The liq. lubricant contg. phosphorus is selected from a group consisting of esterified phosphorus compounds such as acidic phosphoric esters and condensed phosphoric acid such as chain polyphosphoric acid and mineral oil, polyol ester or the like is used as a medium. A high film is formed by lubricating the steel material at about 100-450 deg.C.