Hard coatings for lubrication reduction in metal forming

Abstract

Different forming processes were investigated to evaluate the possibility of reducing the usage of lubricants. A successful way to minimize the consumption of lubricants is to use tools which are covered with PVD hard coatings deposited by the cathodic vacuum arc evaporation. The most promising coating in use was the CrN coating. It becomes evident that neat stamping oils may be substituted by water diluted emulsions when working with coated tools in the forming process. Four main effects were observed: reduction of lubricants up a factor to 85% of additive concentration, increase of tool life up a factor to 169 (first polishing), increase of working speed up a factor to 2 and reduction of washing processes. These effects lower the production costs and decrease the environmental charge.