KARAKTERISASI SAMBUNGAN SPOT TIG WELDING DENGAN MATERIAL STAINLESS STEEL 304
Abstract
Spot TIG welding is one of the spot welding methods where the welding is done only on one side of material. One of the factors influencing the connection quality of the welding point is the current and the length of time during the welding process. The purpose of this study is to determine the effect of current variation and welding time on microstructutre, hardness value and tensile load capacity in stainless steel 304.
The type of connection used is the lap joint following the standard AWS D8.9-97 (American Welding Society) with a specimen length of 100 mm and a wdth of 30 mm, after that a midpoint for the area to be welded with a size of 30 mm x 30 mm is made. Protective gas that will be used in this research is argon with a gas flow rate of 10 liter/minute and is made constant. Varied with electric current 100 A, 110 A, 120 A, 130 A and welding time of 3 and 4 seconds. The test that will be carried out is the micro structure test, microvicers hardness test with a load of 200 gf with a pressure duration of 5 seconds and a shear tensile test with a speed of 5 mm per minute.
The results of the observation of the microstructure are dominated by austenite elements and chrome carbide which in stainless steel 304 material has a Cr content of 18,24%. The highest hardness value of 202 HV, while the lowest hardness value is in the base metal with a hardness value 160 HV. The highest tensile load capacity is obtained ad a current of 130 A with a welding time of 4 seconds with a value of the tensile veban capacity of 3,38 KN, while the lowest tensile load capacity value is at a current of 100 A with a tensile load capacity of 1,78 KN. The increase in welding current and time is directly proportional to the diameter of the resulting nugget