Comparative study of electrogas and shielded metal arc welding processes on steel A537 welded joints

Abstract

In this research, the electro-gas welding process was compared with a shielded metal arc welding process for welding steel A573 from a mechanical properties point of view. Visual and radiographic inspections confirmed the soundness of weldments produced by electro-gas welding and shielded metal arc welding techniques. Various assessments were performed, including hardness, tensile strength, V-notch impact toughness, macrostructure, microstructure, and electrochemical tests. The mechanical properties of the two welding processes were closely matched, with an average tensile strength of 590 MPa for electro-gas welding and 585 MPa for shielded metal arc welding. Furthermore, the influence of welding variables, such as groove design and heat input, on the welded joints’ quality, mechanical properties, and electrochemical behavior was thoroughly examined. Dilution estimates, particularly for the electro-gas welding process, were around 35%, and a significant similarity was observed between the chemical composition determined through dilution calculations and that obtained from chemical analysis using an arc spark emission spectrometer. Notably, the electro-gas welding process demonstrated exceptional productivity, surpassing the shielded metal arc welding process by more than elevenfold. The optimum welding parameters for the electro-gas welding process were identified to achieve superior mechanical properties, low corrosion rates, and reduced consumption of the welding electrodes. This included adopting a single V type and groove angle of 30° instead of 60°, resulting in a 23% reduction in economic costs. Selecting an appropriate heat input within the range of 12 to 14 kJ/mm further contributed to enhancing overall welding efficiency.