摘要 |
A bath for treating metal surfaces for the formation thereon of composite films for the cold working of metal advantageously comprises an otherwise conventional conversion coating bath that also contains organic cationic polymer having at least 1 cationic nitrogen atom per molecule and having a molecular weight of 1,000 to 1,000,000, or a salt of such a polymer. Major improvements in the lubrication properties, particularly in the seizure resistance, can be achieved by applying out a conventional lubrication treatment on such a composite film. Specifically, practical operating limits in metal cold working, e.g., the working degree or ratio, working speed, tool life, and the like, can be increased in a single step. This is useful in terms of improving productivity, product stability, cost reduction, and the like. |