Investigation of extrudability of different aluminum alloys by using the method of hot extrusion

Abstract

Aluminum extrusion is a very important forming process in metal industries. Byusing different dies and technologies, high variety of products can be produced byusing the method extrusion. Extrudability is an important parameter for extrusion processes. For evaluating extrudability of a material not only force and energyrequirements must be investigated but also surface quality and mechanical properties ofproduct must be considered properly.In this study, by using the method hot extrusion, extrudabilities of AA 6063 andAA 7075 aluminum alloys are investigated. Furthermore, by using die-bearing angled dies with relief and choke systems, effect of die-bearing angle on the extrudability ofthese alloys is tried to be evaluated. Three different choke dies with die-bearing angleof 1.5o choke , 1o choke , 0.5o angle, one type of relief die with die-bearing angle of 0.3o relief adding to all these a standard extrusion die, with no angle system is used forexperiments. During experiments, AA 6063 and AA 7075 alloys are used as billetswith 30 mm diameter and 80 mm length. A special designed hydraulic hot extrusionpress with 350 bars of maximum extrusion pressure is used for extruding the billets. Inorder to discuss results of experiments properly, SEM images of samples are obtained, for detecting surface qualities of samples roughness test is conducted and for evaluatingmechanical properties of samples, tensile test and hardness test are made. Also forinvestigating flow behaviours of samples during extrusion a special microstructuralstudy is made.