Journal Published Online: 16 June 2023
Volume 51, Issue 6

Evaluation of Mechanical and Microstructural Properties of High-Temperature Hastelloy X Alloy-Welded Joints Made by Laser Welding Process

CODEN: JTEVAB

Abstract

The usage of Hastelloy X (HX) is crucial in high-temperature applications, and its joining is needed in industries. When HX is welded using traditional methods, the microsegregation of molybdenum- and chromium-rich components causes the material to crack in the final stage of welding solidification. To overcome this, in this current work, HX alloy specimens were welded by a carbon dioxide laser welding process autogenously, which provides low heat input to prevent carbide phase segregation while maintaining a complete depth of penetration. Laser power, welding speed, and focal length were chosen as input parameters with three levels for each input, and the experiments were conducted following Taguchi’s L9 orthogonal array with a suitable combination of the parameters. A structural study was done to analyze weld bead geometry and the microstructure of the weld interface through an optical microscope and scanning electron microscope. Elements present at the weld zone were confirmed through energy-dispersive X-ray analysis (EDAX). The mechanical properties of the joints were tested as per ASTM standards. Mechanical results showed that the tensile strength of a joint maintained a level with a slight decrease in weldment compared with the base metal and maintained the same in the impact test as well. Weld joint efficiency was estimated, and it showed a maximum of 93 %. Hardness was increased with a decrease in welding speed at 3,200 W laser power. The grain size of 39.5 μm had a tensile strength of 690 MPa, but the grain size of 59.88 μm had 540 MPa. The grain sizes of the samples and their orientation with austenite were shown by electron backscatter diffraction results.

Author Information

Sathishkumar, G.
Department of Production Engineering, National Institute of Technology Trichy, Tiruchirappalli, Tamil Nadu, India
Sathiya, P.
Department of Production Engineering, National Institute of Technology Trichy, Tiruchirappalli, Tamil Nadu, India
Senthil Murugan, S.
Department of Mechanical Engineering, Rajalakshmi Engineering College, Chennai, Tamil Nadu, India
Pages: 21
Price: $25.00
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Stock #: JTE20220653
ISSN: 0090-3973
DOI: 10.1520/JTE20220653