Assessment of V influence on the microstructure and mechanical behavior of high strength low alloy steel welded joints

The analysis of the microstructural evolution and mechanical behavior of high-strength low-alloy (HSLA) steels subjected to different manufacturing processes is essential to evaluate their performance and durability. This approach is important in the development of multi-pass welds, as the intercritical coarse-grain heat-affected zone (ICCGHAZ) may experience a significant decrease in mechanical behavior, due to the formation of phases such as martensite/austenite (M/A). The objective of this work is to analyze the influence of the addition of vanadium in S355 steel plates welded by the GMAW process, using multiple welding passes. The microstructural analysis reveals the presence of martensite, bainite, and ferrite in the HAZ, along with M/A constituents with blocky and stringer morphologies. Hardness tests show an increase in the variants with vanadium, which can be attributed to the microalloying effect. Furthermore, the results of tensile tests indicate that the vanadium does not compromise the mechanical performance of the joints.