ANALISIS VARIASI SHIELDING GAS DAN DAYA (POWER) PADA PENGELASAN LASER BEAM WELDING (LBW) JENIS FIBER LASER PADA MATERIAL SS400 TERHADAP SIFAT MEKANIK DAN STRUKTUR MIKRO

Abstract

This research evaluates the effectiveness of Laser Beam Welding (LBW) with a Fiber Laser on SS400 material, addressing defects commonly encountered with Gas Metal Arc Welding (GMAW) on thin plates. It examines the impact of power variations (60%, 65%, 70%) and protective gases (97.5% Argon and 100% CO2) on welding performance. Testing included visual inspections, tensile strength, hardness, and metallography. Visual tests confirmed all variations met acceptance criteria. The highest tensile strength of 518.4 MPa was achieved with 100% CO2 at 70% power, while the lowest was 513.85 MPa with CO2 at 60% power. For Argon, the highest tensile strength was 485.25 MPa at 70% power, and the lowest was 402.25 MPa at 60% power. Macro testing revealed the best penetration of 1.9 mm with 100% CO2 at 70% power and the lowest of 1.6 mm at 60% power. For Argon, the highest penetration was 1.7 mm at 70% power, and the lowest was 1.5 mm at 60% power. Microstructure analysis showed that the base metal was ferritic, with the weld metal containing both ferrite and pearlite phases, the latter being more dominant. Hardness tests indicated that CO2 with 70% power had the highest hardness of 250.5 HVN, while Argon at 70% power had 243.33 HVN. CO2 provided superior tensile strength and penetration, while Argon offered a better visual appearance.