DISSIMILAR SPOT WELDED BETWEEN ALUMINUM AND STEEL USING COPPER FILLER

Abstract

The welding point on the metal weld joints is necessary to facilitate the connection of two different materials and material cost savings. It is widely used in manufacturing, especially the automotive and shipbuilding industries. The purpose of this study to determine the quality of the welding by using the welding machine DN-16-1-type AC-point welder against physical and mechanical characteristics of welded joints between steel SS400 point with aluminum Al6061.

Welding parameters used are electricity voltage, long welding, the thickness of aluminum, and the addition of filler. Voltage electricity using 3.20 volts and 2.67 volts at 10 seconds, 7.5 seconds, and 5 seconds. This study used two different materials is aluminum alloy Al6061 thickness 6 mm, 5 mm, 4 mm and 3 mm and low carbon steel SS400 thickness 2,3 mm with a material thickness of 0.2 mm copper filler. Making specimen welding refers to the standard JIS Z 3139 and for testing the structure of the results of the welds using the macro image and a microphotograph using optical microscopy, testing the tensile strength of the connection with the method of tensile testing, testing microstructure and composition of the nugget to test SEM-EDAX, and testing of violence micro Vickers methods.

Welding research specimens obtained the best results in the voltage variation of 2.67 volts welding time 10 seconds, the thickness of 5 mm aluminum and 3.20 volt voltage variation 5 seconds long welding, aluminum thickness of 5 mm. In the tensile test with filler obtained the highest results obtained 34.58 MPa, a low of 12.45 MPa. While the tensile strength without filler gained 106.40 Mpa. Structure nugget optical microscopy test results showed the atoms experience in the area intermetallic bonding interface FeAl and Fe₃Al by forming a boundary line between the two materials and columnar appears to grow. Vickers hardness test results on the nugget area have a high hardness at 623.33 HVN at a voltage of 3.20 volts, long welding 5 seconds, and the thickness of the aluminum material on 3 mm without filler.