ENHANCED BOUNDARY LUBRICATION BY POTENTIAL CONTROL DURING COPPER WIREDRAWING

Metal deformation process, such as wire drawing, is conventionally per formed under open-circuit conditions. Lubrication is heavily dependent on the surface conditions of the wire. The surface condition of the w ire depends on the electrochemical reactions once the wire contacts wi th the emulsion lubricant. An oxide layer on the incoming wire could b e removed partially or completely and repassivation occurs on the aspe rities of the wire after abrasion. Adsorption of fatty acid on the oxi de layer of the wire could play a vital part in the efficiency of boun dary lubrication. Friction could be reduced when a proper potential is applied between the wire and the auxiliary tube before the drawing di es. The reduction of friction detected at Various potentials depended on the lubricant chemical composition. Surface quality could be signif icantly improved and energy consumption substantially reduced by the p otential control. (C) 1997 Elsevier Science S.A.