Friction Welding of Aluminum Alloy Applied Positioning Control Process

摘要

Friction welding is one of solid-state welding processes that usefriction heating to join members. Aluminum alloy is preferableperformances by their high specific strength, however aluminum alloyseems to be difficulties to assemble by fusion welding processes.Friction welding process is a superior characteristics on mechanicalproperties and on production performances, however this process islimited to apply joining of round bar materials due to lack ofpositioning control capability. Positioning control means controlling the stopping position of main rotating spindle when the joining wascompleted. This process limitation has been overcome introducingrecent servo systems. This study is carried out to clarify effect ofprocess parameters on mechanical properties of positioning controlledjoints of aluminum alloy, A6061 in case of square cross section. Inaddition, the effect of geometry is revealed on friction welding incomparison with ordinary round bar. Two type specimens are prepairedin this study. One is square sectional bar of 17mm on a side. Other isordinary round bar of 19mm in diameter. Cross sectional area of twotype specimens are almost equivalent. In the result, Positioning controlprocess is successfully performed, and mechanical properties arealmost equivalent to conventional friction welding process whensufficient upset distance is applied. It seems to yield imperfection at thecorner of square joints when the small upset distance. Higher upset loadand longer friction time make a sufficient contact area in weld interfaceresulting in larger upset distance eliminating weld imperfection. Widthof softened zones in both sections, square and round, is almostequivalent under the optimized parameters.