Challenges and opportunities to develop the method of joining dissimilar material aluminium-steel by using Rotational Friction Welding (RFW)

Abstract

The combination of the lightweight AL 6061 and high-strength steel SWRM 1008 is utilized by the industrial sector, including the automotive industry to make bumper reinforcement. The properties of AL 6061 and SWRM 1008 steel have specific differences so an appropriate welding method is needed. This is a challenge and an opportunity for its application in the future. Rotational friction welding (RFW) is one of several welding processes that can be applied to join AL 6061 with SWRM 1008 and furthermore, the welding is environmental. The occurrence of diffusion between AL 6061 and SWRM 1008 is influenced by the heating temperature and forging pressure. Due to different melting temperature the steel in this research has been preheated. Al 6061 has a lower melting temperature than SWRM 1008 and a male-female shape has been made so that excessive upset did not be overformed and the forging process ran optimally. The welding process used rotational friction welding between Al 6061 and SWRM 1008 with preheat temperature 3500C, rotational speed 800 rpm, friction pressure 2 Mpa, and forging pressure 3 Mpa. The results of the joining were then tested for tensile strength and micro-photos. The preheat to SWRM 1008 before the welding process causes softening of the aluminium surface immediately after contact. Excessive softening of the aluminium surface establishes an upset before diffusion occurs. IMC will form well under high shear stress and forging pressure. The welding process at low pressure obtained a connection tensile strength value of 65.2Mpa even though it had been preheated before welding took place. From this research, we can know if rotational friction welding gives opportunities to join the AL 6061 with SWRM1008.