This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κ_III structure with β′ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κ_III structure in between.

1) The bead geometry of titanium alloys is optimized by the Taguchi method. At optimal welding conditions, the bead width of Ti-6Al-4V is wider than the Ti-3Al- 2.5V due to the lower thermal conductivity and higher heat capacity of Ti-6Al-4V.

In the contemporary shipbuilding industry, the construction of Liquefied Natural Gas (LNG) carriers represents a pinnacle of high-value manufacturing that demands extreme precision. The fabrication of membrane-type containment systems, such as Mark III and NO96, relies heavily on the lap-joint welding of thin corrugated plates made of STS 304L or Invar alloy. Recently, the imperative for welding automation has intensified due to the critical shortage of skilled welders and the stringent requirements for gas leakage prevention. However, the application of Laser Vision Sensors (LVS) for seam tracking has been hindered by specular reflection, intense arc interference, and mechanical interference from clamping devices. This study aims to systematically evaluate the seam recognition performance of an LVS-based system under these adverse conditions. A robotic welding system integrated with a coaxial LVS module was constructed to conduct experiments on STS 304L corrugated lap joints. The influence of optical and geometric parameters, including laser power and camera angle, on the quality of acquired laser profiles was analyzed quantitatively. To enhance robustness, the sensor’s logarithmic gain settings were optimized to mitigate interference from TIG arc under varying heat inputs. The results demonstrate that a 200mW line laser at a 50-60° camera angle provides the highest height-difference detection resolution for lap joints. Finally, this research confirms the optical feasibility of LVS in LNG tank fabrication and suggests future directions for hybrid or AI-enhanced sensing solutions.