Evaluation of lubricants for cold forming of steels by double-cup extrusion tests

The double-cup extrusion testing method was chosen for measuring the pressure and material flow parameters in order to quantify the frictional shear factor between the workpiece and the forming tool in cold metal forming processes. The test was adapted to be used under production conditions and applied to characterize and compare the lubrication properties of different types of lubricants and coatings.;It was found to be a useful approach to estimate the relative efficiency of different lubricants and coating methods. It indicated that one specific lubricant has significantly superior lubricant characteristics than others.;FEA analysis of the experimental setup was constructed to generate calibration curves for the coefficient of friction, m, at various values of m and deformation stroke by using the metal forming software package ANTARES. Statistical techniques were utilized to calculate the mean and variance of results obtained for various combinations of the experimental control variables.;Additional efforts are needed in order to make the test results more sensitive to slight variations of friction within a given lubrication method