Determination of Optimal Weld Parameter for Joining Titanium Alloys by Gas Tungsten Arc Welding using Taguchi Method

• Published in: Journal of Welding and Joining Vol. 39; no. 1; pp. 81 - 88
• Main Authors: Huda, Nazmul, Kim, Jae Won, Ji, Changwook, Nam, Dae-Geun, Park, Yeong-Do
• Format: Journal Article
• Language: English
• Published: 대한용접·접합학회 28.02.2021; 대한용접접합학회
• Subjects: 기계공학; Mechanical properties; Titanium alloys; Optimal parameters; Microstructure; Taguchi method
• ISSN: 2466-2232; 2466-2100
• DOI: 10.5781/JWJ.2021.39.1.10

The optimal parameters for joining two different titanium alloys were determined by the Taguchi method and ap plied in similar and dissimilar joining of conventional Ti-6Al-4V and newly developed Ti-3Al-2.5V alloys. The mi crostructures of the two alloys and their mechanical properties were comparatively evaluated at the optimal parameters. The Ti-6Al-4V alloy showed a larger back bead width than that of Ti-3Al-2.5V under similar heat input, because of its lower thermal conductivity and higher specific heat capacity. The welded zone of Ti-3Al-2.5V con tained a retained beta phase, which was absent in that of Ti-6Al-4V. This indicates that the transformation of the Ti-3Al-2.5V weld metal starts above the martensite temperature, while it starts below the martensite temperature for Ti-6Al-4V. The failure of the welded specimen occurred in the base metal for both the titanium alloys, which in dicates the superior weld quality. However, the welded Ti-6Al-4V showed superior tensile strength to that of the Ti-3Al-2.5V weld under optimal conditions, owing the high beta phase fraction in its base metal. Meanwhile, it showed inferior ductility to that of Ti-3Al-2.5V because of its coarser beta phase. KCI Citation Count: 0