Welding of S960MC with undermatching filler material

Abstract

High strength structural steels are in high demand thanks to their favorable mechanical properties. They offer high strength with sufficient toughness and good forming capabilities. Applications range from shipbuilding, to offshore constructions, cranes, and pipelines. A lot of current research focuses on weldability of high strength low alloy (HSLA) steels, especially improving the toughness in the weld zone, i.e., weld metal (WM) and heat affected zone (HAZ). In the present work, four different fusion welding processes using undermatching filler metal are compared on 8-mm thick sheets of S960MC structural steel. The welding processes include electron beam, laser hybrid, plasma, and gas metal arc welding. The welded joints are characterized by means of mechanical testing, tensile, impact, and hardness testing, and microstructural investigaton, light optical, and scanning electron microscopy. Furthermore, microprobe analysis of the weld metal was used to investigate the chemical composition of the weld metal.