Abstract
This paper aimed at studying the effects of adding aluminum into welding pool of low carbon steel on mechanical properties, microstructure, and chemical composition of the welding hardfacing using gas tungsten arc welding process. In this work, a speed of adding aluminum welding wire was varied from 5-15 m/min. As found from the experimental results, the hardness of the welding hardfacing was highest at 885.87 HV when using the welding wire speed at 15 m/min, and it decreased with reducing the speed of the welding wire. The minimum wear rate of the weld was at 0.123 g/min. when testing at 10 m/min. The investigation of microstructure and chemical composition revealed that the welding sample from the test with welding rate of 15 m/min had a greater contribution of aluminum than iron. The welding had a microstructure of Eutectic FeAl and Lamellar Eutectic FeAl2. The cracks were also found between these structures. However, when the speed of adding welding wire was lowered, the concentration of iron in the welding was higher than aluminum. In this case, a eutectic FeAl with needle-like structure was found, this similarly formed due to a partial eutectic reaction on main structure of FeAl3. In addition, no crack was found when adding aluminum welding wire with a lower speed.
Keywords : welding hardfacing , chemical composition, low carbon steel, gas tungsten arc welding
