Effect of previous heating treatments conditions and gas metal arc welding (GMAW) on mechanical and microstructural properties of HSLA steel DOMEX 460MC

To meet the growing demands of various industries for materials that are not only highly resistant but also possess good mechanical properties at a reasonable cost, high strength low alloy steels (HSLA) have been developed. However, the low ductility associated with these steels can pose challenges in their application. Moreover, many components undergo gas metal arc welding, further highlighting the importance of ductility in steel conformation. The quest for an optimal heat treatment method capable of adjusting the mechanical properties to meet specific design requirements while enhancing the material’s ductility remains a critical issue. This study presents a comprehensive analysis of the microstructural and mechanical properties of a HSLA steel variant, DOMEX 460MC, subjected to three distinct heat treatment regimes: 400 °C, 580 °C, and 700 °C. Brinell hardness tests and microstructural analyses were conducted for each condition, alongside the evaluation of mechanical behavior through tensile testing following ASTM E8M-04 standards. The findings revealed that heat treatments at 580 °C and 400 °C notably improved ductility, while ductility remained consistent with the original steel at 700 °C. Furthermore, the heat treatment conducted at 580 °C exhibited the highest ultimate strength value among all heat-treated tested conditions.