Experiments on the effect of thermoelectric current magnetic field on welding of 60-mm thick dissimilar steels

Abstract

The work describes a method for measuring the magnetic field induced by thermoelectric currents in control points above welded specimens and presents the measurement results. The dissimilar 60-mm thick steel samples are welded by electron-beam welding (EBW). The grades of the pairs of steels are 09Mn2Si + 12Cr18Ni10Ti, 09Mn2Si + 20Cr13 and 20Cr13 + 12Cr18Ni10Ti. The study shows that the electron beam in the weld root deflects towards the material with larger positive potential of integral thermal EMF. The deflection is uneven along the specimens, which necessitates taking into account the geometry of welding joints when elaborating the mathematical models of the process. Maximum deflection for the studied pairs of materials correspondingly amounts to 0.6, 2,8 and 3.8 mm, which is critical for producing a high-quality seam. In addition, the alteration of magnetic induction in control points during EBW was obtained.