EVALUASI PENGELASAN FCAW PADA KORT NOZZLE KAPAL TUGBOAT 28 M MENGGUNAKAN METODE AIR PRESSURE TEST

Abstract

The quality of welded joints is a crucial factor in the shipbuilding industry to ensure structural integrity, particularly for vital components such as the kort nozzle, which plays a key role in enhancing propulsion efficiency. Although Flux-Cored Arc Welding (FCAW) is widely utilized due to its high productivity, improper selection of welding parameters poses a significant risk of structural failure. This study focuses on evaluating the quality of FCAW welding on the kort nozzle of a 28M Tugboat by analyzing how variations in electrical current affect the strength and tightness of the welded joints. The research methodology employed is experimental, comparing three variations of welding current: 200 A, 250 A, and 300 A, on steel materials according to project standards. The evaluation process was conducted in two stages: a visual inspection referencing the AWS D1.1 standard to monitor surface defects, and an air pressure test with a pressure of 0.2 bar in accordance with BKI (Classification Bureau of Indonesia) rules to verify the tightness of the welds. The evaluation results indicate that the 250 A current produced the most optimal joint quality, achieving a fully airtight status (ACC). Conversely, the 200 A current resulted in insufficient penetration, triggering seven leak points caused by defects such as lack of fusion, porosity, and slag inclusions. Meanwhile, the 300 A current led to excessive heat input, which induced undercut and hot crack defects. In conclusion, a current parameter of 250 A is the most ideal for kort nozzle fabrication in this project, as it successfully meets both visual quality standards and the required technical specifications for airtightness.