Investigation of mechanical properties and parametric optimization of the dissimilar GTAW of AISI 304 stainless steel and low carbon steel

Abstract

Purpose

The purpose of this study is to conduct gas tungsten arc dissimilar welding of AISI 304 stainless steel and low carbon steel within a process window so as to investigate the effects of current, speed and gas flow rate (GFR) on the microstructure and mechanical properties of the weldments.

Design/methodology/approach

The welding experiment was carried out at different combinations of parameters using WN-250S Kaierda electric welding machine. A combination of scanning electron microscopy and energy dispersive X-ray spectroscopy was used to examine the microstructure of the weldments. Micro-hardness and tensile tests were performed using Vickers hardness tester and Instron universal testing machine, respectively. ANOVA was used to analyze the significance of the parameters on the mechanical properties.

Findings

The microstructure of the weld region is characterized with dendritic structure with the existence of ferrite and austenite phases. The utilized parameters show significant effects on the ultimate tensile strength (UTS) of the weldments. The current and GFR were found to be the most and least significant factors, respectively. Both the grain size and weld penetration contributed to the UTS of the weldments. The UTS (427-886 MPa) increased with decreasing current and welding speed. In all samples, the weld region exhibited higher hardness (297-396 HV) than the HAZ in the base metals (maximum of 223 Â ± 6 HV). All the three factors show significant effect with the welding speed contributing mostly to the hardness of the weld region.

Originality/value

The parametric combination that gives the optimum mechanical performance of the dissimilar gas tungsten arc weldments of AISI 304 stainless steel and low carbon steel was established.

Citation

Ogedengbe, T.I., Abioye, T.E. and Ekpemogu, A.I. (2018), "Investigation of mechanical properties and parametric optimization of the dissimilar GTAW of AISI 304 stainless steel and low carbon steel", World Journal of Engineering, Vol. 15 No. 5, pp. 584-591. https://doi.org/10.1108/WJE-12-2017-0412