Friction Coefficients on Compression Testing Of AA6060 and 42CrMo4 with Different Lubrication Conditions

Friction at the interface of compression die/work piece plays an important role in the overall behaviour of metal forming processes. This work is dealing with the determination of the friction coefficient on compression loading of the aluminum alloy AA6060 and the steel 42CrMo4 as under different lubrication conditions.The coefficient of friction was determined using cylindrical specimens with different diameter d_o/ height h_o ratio (d_o/h_o = 0.5, 0.67, 1.43 and 2.0). The initial specimens diameter was 4mm. Different lubrication conditions were applied: (a) dry, (b) lubrication with Molykote, (c) one Teflon layer and (d) two Teflon layers with oil film between them. The test materials were the aluminum alloy AA6060 and the steel 42CrMo4. Friction coefficients as a function of the strain were determined by the description of the curves of the deformation resistance against the d_o/h_o values at different deformation degrees and different lubrication conditions. A comparative flow curves were determined after the elimination of the friction effect of the different d_o/h_o values.