Document Type : Original Research Article
Authors
1
MSc, Material Science & Engineering, MavadKaran Engineering Company, Mapna Group, Tehran, Iran.
2
M.Sc, Mechanical Engineering, MavadKaran Engineering Company, Mapna Group, Tehran, Iran.
10.22034/frj.2025.542238.1209
Abstract
Resistance spot welding is the most common welding process for joining metal sheets. In the power plant parts manufacturing industry, spot welding of nickel-based superalloy sheets, which have low weldability, is a challenging task. In resistance spot welding, three parameters of current intensity, welding time and electrode force have the greatest effect on the quality of the joints. In this research, the role and effects of these three variables in resistance spot welding of Haynes230 nickel-based superalloy sheet, which is widely used in the construction of gas turbine combustion chambers, have been investigated. In order to evaluate the quality of the welded samples, destructive and non-destructive tests such as metallographic tests, including the examination of the microstructure of weld areas by optical and electron microscopes, inspection of the weld area by penetrating liquid to identify surface cracks and Holes, radiography test to identify the internal defects of the weld area, microhardness test, Peel test to evaluate the weld strength, tension-shear test at ambient and high temperature to determine the shear strength of welds were performed. Also, the resistance spot welding process was simulated in ANSYS software by a finite element model of mechanical, electrical and thermal coupling using APDL code. In this regard, the temperature distribution, shape and size of the weld button were predicted and then, in order to validate, the element model and the geometry of the weld button obtained from the simulation results were compared with the experimental results, and a good match was observed between them. The optimal process parameters were identified as a welding current of 5800 A, welding time of 9 cycles, and electrode force of 5.6 kN, which resulted in a weld nugget with a diameter of 5.2 mm—exceeding the GE standard minimum of 5.08 mm for 1.6-mm-thick sheets—and achieved a shear strength of 13.4 kN at room temperature and 339 MPa at 649°C.
Keywords
Subjects
