Effect of welding parameters on dissimilar pulsed laser joint between nickel-based alloy Hastelloy X and austenitic stainless steel AISI 304L

Abstract

The present study aims to investigate the strength and microstructure of dissimilar weld joints composed of Hastelloy X, i.e., a nickel-based superalloy, and austenitic stainless steel 304L. Nd-YAG solid-state pulsed laser is used to perform welding between these two alloys. The effects of welding speed, laser power, and pulse width on the joint strength are studied by changing the values of the mentioned parameters. Then, the test samples were adopted to conduct uniaxial tensile tests at room temperature. The results obtained from the uniaxial tensile tests showed that the pulse width and laser beam power had maximum effects on the strength of the joint. Results also indicated that a dissimilar joint with the highest quality could be obtained by optimizing the welding power, beam pulse width, and welding speed. Given the selected parameters for laser welding, the tensile strength of the joint was equal to 95.5% of the weaker alloy strength (AISI 304L), which showed excellent quality of the weld. Furthermore, changes in the composition of the constituting elements of the joint were investigated using the Energy-Dispersive XRay Spectroscopy (EDS) tests and scanning electron microscope. The results of the EDS tests indicated that a change in the composition of the constituting elements in this zone occurred on a regular basis.