BLACK PLATE WITH IMPROVED SURFACE LUBRICITY

摘要

To prevent galling during the drawing and ironing process, black plate is provided with an economical coating for improving surface lubricity. Cold-reduced strip is rinsed with a solution containing soluble salts of manganese and sulfur, e.g. MnSO4; the strip is dried and then heated to above 800 DEG F in a reducing atmosphere, such as HNX. Heating is conducted at a temperature sufficient to reduce the sulfates and provide a surface coating of MnS in which the surface sulfur concentration is in excess of 0.5%.