High-Speed Drawing of Al Alloy Wire by Diamond-Coated Drawing Die Under Environmentally Friendly Water-Based Emulsion Lubrication

Abstract

It is environmentally friendly to use water-based emulsion instead of the oil when cold drawing Al alloy production. In this research, adopting specially prepared water-based emulsion, contact angles and tribological properties of as-selected multilayer diamond films are clarified. The contact angle on diamond film is much smaller than that on WC-Co with the same surface roughness, and tribological behaviors of the diamond film are much better. The effects of surface roughness Ra of the film, lubrication, and water content in the emulsion W are studied, indicating that the contact angle increases with W or Ra. For the diamond film, lower Ra is beneficial for reducing the coefficient of friction (COF), Al alloy ball wear and oxidation, while lower W contributes to the reduction of the COF, ball oxidation, and coated disk wear. Finally, high-speed drawing of high-quality 6021 Al alloy wires (AWs) is accomplished, proving that using coated drawing dies, the water-based emulsion (W < 80 vol %) can totally replace oil, and coated dies under the water-based emulsion lubrication present much elongated lifetime and can guarantee the production quality, compared to uncoated ones under the oil lubrication, in spite of slightly severer wire oxidation.