Abstract
Hastelloy X (HX) is a solid solution–strengthened nickel‐based superalloy that is frequently utilized in high‐temperature applications where traditional welding frequently results in solidification cracking due to microsegregation that is rich in Mo and Cr. In order to address these problems, this study investigates the application of CO
2
laser welding, which achieves full‐depth penetration with minimal heat input. Using an
L
9
orthogonal array, three crucial parameters—laser power, welding speed, and focal length—were adjusted at three different levels. Tensile, impact, and microhardness testing were used to assess mechanical characteristics, while optical microscopy (OM), FESEM, EBSD, color mapping, and EDX were used to describe welds. With only a minor decrease in tensile strength, the resultant junctions showed mechanical characteristics similar to those of the base metal and were free of porosity and fractures. At lower welding speeds, especially at 3200 W, hardness increased. Strength was significantly influenced by grain size: Coarser grains (59.88 µm) reduced strength to around 540 MPa, whereas finer grains (39.5 µm) yielded a tensile strength of about 690 MPa. IPF maps showed mixed equiaxed and dendritic structures, while EBSD results emphasized the role of grain boundary character in strengthening. All things considered, CO
2
laser welding showed efficacy in creating flawless HX joints with improved performance and refined microstructures, providing a viable substitute for traditional welding techniques.