Enhanced boundary lubrication by potential control during copper wire drawing

Metal deformation process, such as wire drawing, is conventionally performed under open-circuit conditions. Lubrication is heavily dependent on the surface conditions of the wire. The surface condition of the wire depends on the electrochemical reactions once the wire contacts with the emulsion lubricant. An oxide layer on the incoming wire could be removed partially or completely and repassivation occurs on the asperities of the wire after abrasion. Adsorption of fatty acid on the oxide layer of the wire could play a vital part in the efficiency of boundary lubrication. Friction could be reduced when a proper potential is applied between the wire and the auxiliary tube before the drawing dies. The reduction of friction detected at Various potentials depended on the lubricant chemical composition. Surface quality could be significantly improved and energy consumption substantially reduced by the potential control. (C) 1997 Elsevier Science S.A.