Lubrication and Friction of Magnesium Alloys in Warm Forging

In order to realize precision forging of magnesium alloys, the frictional behavior of ZK60 (Mg-6%Zn-0.5%Zr) is studied. At room temperature, the friction test of ZK60 sliding over the surfaces of cemented carbide tool with and without TiC+TiCN+TiN and DLC (diamond like carbon) coating is carried out. It is found that the DLC coated film is effective to reduce the coefficient of friction and the oxide film of magnesium increases friction. For warm forging, ring compression tests are carried out at temperatures from 200 °C to 300 °C. Several liquid lubricants are applied onto the tool surfaces by controlling the film thickness and the effect of lubrication on friction is examined. Some methods for heating and lubrication for warm forging of magnesium alloys are suggested.