ANALISIS PERBANDINGAN SIFAT MEKANIK PENGELASAN MULTILAYER BAJA TAHAN KARAT 316L PADA PENGELASAN GTAW DAN SMAW

Abstract

Multilayer welding is a multiple times welding that do on a material which has a certain thickness until it was not possible to do a single layer welding. Multilayer welding is widely used in assembling industry of boilers, heat exchangers, pressure vessel etc. This research was conducted two variations multilayer welding processes; they are GTAW-GTAW, GTAW-SMAW on stainless steel 316L. Filer metal that used in GTAW welding is TGS316L and electrodes that used for SMAW welding are ER 316L. Penetrant testing does testing results of porosity defects and cracks. The observation of microstructure in the done specimens welding used an optical microscope. Hardness testing was conducted microvikers method. Both of GTAW-GTAW welding and GTAW-SMAW welding did not find any porosity defects and cracks on the surface of the weld area. Grains in the form of GTAW-GTAW welding look smoother than the GTAW-SMAW welding. It causes the tensile strength of GTAW- GTAW welding is higher than the GTAWSMAW

welding. In addition, the highest hardness results that are known in the second layer HAZ region on GTAW-GTAW welding is about 370 VHN and the lowest hardness found in the HAZ area which is in SMAW-GTAW welding is about 195 VHN. The test results said that GTAW-GTAW welding have better mechanical characteristic than GTAW-SMAW welding, nevertheless GTAW-SMAW welding still can be used for welding on the assembling of Shell circulation Heater in heat exchangers because when it viewed from the mechanical characteristic obtained from testing is still appropriate standard ASME section IX.