METAL DRAWING BY MEANS OF SOLID SOAP FILMS

Solid soap films are used alternatively to conventional powder lubrica tion in cold drawing. The material to be formed is initially coated wi th an aqueous soap dispersion and subsequently dried in order to obtai n a solid lubricant layer on the surface of the material. The rheologi cal behaviour of these layers is highly effective in the lubrication p rocess during metal drawing. Experimental results give evidence of hig h pressure hydrodynamic lubrication, which is superior to conventional powder-type lubrication, especially when using a double-die drawing t echnique. Both tribological and environmental aspects indicate the hig h potential of this solid-film lubrication, the environmental advantag es referring to a diminution of aggressive chemical substances and of air pollution by lubricant dusts, in the manufacturing process.