Microstructure and mechanical assessment of Inconel 625 and AISI 904L dissimilar joints using high-density welding technique for pressure vessels

• Published in: The International journal of pressure vessels and piping 2024-06, Vol.209, p.105191, Article 105191
• Main Authors: Prabu, S. Senthur, S M, Muthu, N, Beemkumar, Sujai, S., M, Arvind, K, Kailash, Chandran P M, Midhun, Ramkumar, S
• Format: Article
• Language: English
• Subjects: AISI 904L; Inconel 625; Laser welding; Microstructure; Phases; Structural integrity
• ISSN: 0308-0161; 1879-3541
• DOI: 10.1016/j.ijpvp.2024.105191

The dissimilar bimetallic joints of 5 mm thick Inconel 625 and AISI 904L were accomplished through the high-density fiber laser welding (LBW) process. The metallurgical investigation ensured the micro-segregation of Mo and Nb in the dendritic and inter-dendritic regions along with the formation of secondary topologically closed packed (TCP) phases. In addition to the metallurgical studies the Kernal average misorientation (KAM), Schmid factor (SF), and nucleation of the new grains were investigated through Electron backscattered diffraction (EBSD) analysis. The tensile strength opined the occurrence of failure on the 904L side, away from the weld seam ensuring that the joints have a higher strength. The notch tensile showed a higher strength of 678 ± 4 MPa in the weld zone than that of the 904L base alloy. The Charpy V notch studies showed a drastic decrease in the impact toughness with 38 ± 2 J as compared to the base alloys under sudden impact loading at room temperature (RT). •High-density laser welding of Inconel 625 and AISI 904L joints.•Grain refinement, segregation of elements, and precipitation of carbides along the grain boundaries and fusion zone using SEM/EDS analysis.•Meticulous discussion on the metallurgical and structural Integrity of the joints.