Influence of process parameters on the friction coefficient in AlMg3 alloy stripe ironing drawing test

Abstract

Presented in this paper are the results of experimental investigations of influence on friction in the stripe ironing process with double thinning. Applied was modified mathematical model for evaluating influence of lateral force, contact pressure and average absolute roughness height on friction coefficient. Classical model in not suitable for small lateral and drawing forces, and give unreal negative friction coefficient values. Previously proposed and applied here, modified model is more appropriate. Calculated friction coefficient values in that model are more according to reality. 20 mm wide and 3.0 mm thick strips of AlMg3 alloy sheets were used in the single and three-phase process with a maximum thinning deformation of 27%. Appropriate lubricating grease was used in conditions of lower speed of 20 mm/min. Three phase process was realized with variable lateral force of 4, 8 and 12 kN. The applied experimental test procedure enables the precise quantification of lateral force, contact pressure and roughness influence on friction to be established. Test also enables evaluation of lubricants quality. Keywords: modified stripe ironing test, Al alloy, friction coefficient.