Effect of beam oscillation and focusing on the electron beam welded 1100M high strength structural steel joint

Abstract

Abstract The development of ultra-high-strength steels (UHSS) is revolutionizing its need in the diverse field of application, and the main credit going to the new technological advancement in the manufacturing of steels using special heat treatment like the thermomechanical rolled process to produce UHSS with up to 1300 MPa tensile strength in the thicker plate. The steel provides higher strength, toughness, and extensive reduced weight, significant in structural components and higher load lifting vehicles (e.g., mobile cranes, trailers, concrete pump trucks, etc.) with lower fuel consumption. However, welding of UHSS is also a challenge due to their higher crack susceptibility and hardness reduction in the heat-affected zone (HAZ). The study’s main objective is to analyse the effect of beam focus on the weld geometry and the different beam oscillation on the weld microstructure and hardness behaviour of the 1100M EB-welded joint. The S1100M steel samples of the thickness of 15 mm were butt-welded by autogenous electron beam welding (EBW). The study finds that UHSS can be satisfactorily welded with EBW, improving the weld geometry with beam focus. The observed results show that beam oscillation’s microstructural and hardness behaviour was attributed to developing a more uniform microstructure.