Mechanical Properties and Micro Structure of Aluminum Alloys [Al-Mg-Si] as Results of Variation Time in Friction Welding

Abstract

Friction welding is one solution to solve the problems joining of metals which are difficult to be welded by fusion welding such as aluminum. The process was run by rotating a rod upon another metal and force was applied. Consequently, heat arose below the melting point and made the metals molten joined together as force continuously applied. In this research aluminum 6xxx series were used as this metal have good corrosion resistance, good machinability but not ease to weld. Among important parameters in linear welding are friction time, friction pressure and rotation speed; we only concern in the first one. The friction time variations were 20, 45, 80, and 120 seconds respectively. Whereas the pressure and the rotation speed were kept constantly. The joined aluminum then tensile strength tested using universal testing machine, hardness tested using Electrical Brinnel hardness Tester Hauser Henry SA and also observed under optical microscope. The highest tensile strength of 61.07 MPa was gained from friction time of 45 seconds, while the least of only 28.81 MPa when using friction time of 20 seconds. Hardness in the welding areas was almost the same as that of base metal, whereas in the heat affected zone tend to little bit decreased. Friction time of 20 seconds gave the hardest in the welding are almost the same as base metals, whereas the softest as result of 120 friction time. Optical microscope observations show that there were porosities in the welding areas. It probably caused by some trapped gas which formed inter-dendritic porous.