| 摘要 |
A high quality lubricating coating can be provided on iron, carbon steel, and other low alloy steel workpieces before cold working them by electrolysis at a current density of 2 - 20 A/dm<2> for 1 - 30 seconds, with the workpiece as cathode, in an aqueous acidic electrolytic bath containing as its essential constituents water, free acid, 3 to 20 g/L of zinc ions, 3 to 20 g/L of phosphate ions, 3 to 40 g/L of nitrate ions, and substantially no complexing agents for zinc ions, the acidic electrolytic bath also having a zinc ions to phosphate ions weight ratio in the range from 0.7 to 1.4 and a nitrate ions to phosphate ions weight ratio in the range from 0.7 to 2.6. |
