Theoretical and experimental studies on evaluation of friction factor in extrusion process of AA6063 and AA6063 SiCp composites

Abstract

In metal forming processes, the friction between the die and billet newlineinterface plays a major role on the forming load and quality of the finished newlinecomponent. The various methods used to determine the friction factor during newlinemetal forming process are, uniform compression, ring compression, forward newlineextrusion and double cup extrusion tests. Aluminum alloys have good physical properties, such as low newlinedensity, good corrosion resistance, electrical conductivity, thermal newlineconductivity, formability, machinability and weldability. Due to these unique newlinecombinations of properties, Aluminum alloys offer a wide range of newlineengineering applications. AA6063 extrusions are used in structural frame newlineworks. The major constituents of this alloy are Magnesium and Silicon. In newlinethis research work AA6063 has been chosen for investigation. The main objective of this study is to find a suitable methodology newlineto determine the friction factor, and to evaluate the change in the friction newlinefactor with respect to the lubricant, temperature, grain size, area reduction and newlinepercentage of SiCp content, using the forward extrusion process for its newlinespecific advantages. In this work, four types of configurations, viz., channel type, newlinerectangular type, three and two components circular die sets were examined. Among these, the two components circular die set was found suitable, and the newlinesemidie angle was selected by considering the load requirement and area newlinereduction. The selected semidie angle increases with an increase in the area newlinereduction. A theoretical model has been developed for finding the newlineintermediate extrusion load. The experimental friction factor was determined newlineby three models, namely, Altan, Avitzur and Bakhshi-Jooybari. In all the newlinethree models, the friction factors obtained are very close to one another. Lubricants were used at the interface to reduce the friction factor newlineand hence the forming load reduced. Molybdenum disulphide, Graphite and newlineZinc stearate were chosen as lubricants for the extrusion process. newline