ANALISIS PENGARUH VARIASI FLOW RATE PADA MATERIAL PIPA 20 GB/T 8163 DENGAN PROSES LAS GTAW TERHADAP WELDING DEFECT, KEKERASAN, DAN STRUKTUR MIKRO

Abstract

GTAW is a welding method that is often used. However on the site, windy conditions resulted
in less than optimal GTAW results, causing defects. Therefore it is necessary to have a solution to
minimize the effect of wind on the welding results by increasing the flow rate of the shielding gas. The
purpose of this study was to determine the effect of flowrate variations in GTAW welding on welding
defects, hardness values, and microstructure of steel pipes. The method of this research using 3
specimens with flowrate variations of 15 L/min, 20 L/min, and 25 L/min. From radiographic testing, it
was obtained that specimens with a flowrate of 25 L/min had zero defect. In the hardness test, the
highest hardness value was in the variation of the flowrate where in the weld metal it is 184.88 kgf/mm2.
However, the flowrate variation has no significant effect on the hardness value. On micro observation
it was found that the weld metal has a darker color. The conclusion from this study is that variations in
flowrate can reduce welding defects, but do not have a significant effect on the hardness value and
microstructure. This research is expected to contribute to pipe production industry.