Effect of deviations of the chemical composition of high-strength steel and electrode wire on the mechanical properties of narrow-gap welded joints

Abstract

Because of large allowances for the content of alloying elements, the initial chemical composition of welded metal and electrode wires is one of the reasons for the instability of the mechanical properties of welded joints in high-strength steels. Analysis using interpolation models is carried out to determine the dependence of the change of the mechanical properties of welded joints on the cooling time in the polymorphous transformation temperature range 850–500 °C. The experimental results show that the initial instability of the chemical composition of the welded joint has the strongest effect on the impact toughness of the welded joint at a cooling time shorter than 5 s. The instability of mechanical properties of welded joints, determined by variations of the chemical composition of the parent and electrode metals, even in optimum welding conditions is estimated by an error of 815%.