New welding wire for welding high-strength quenched and tempered steels

Abstract

The article is devoted to the complex challenges associated with the development of welding wire for welding high-strength steel in shielding gases.

In the development of welding wire, it is essential to address a number of considerations related to the resistance of welded joints to hot and cold cracking, wire production technology, the regulatory level of mechanical properties, the manufacturability of the welding process, and the environmentally friendly working conditions of welders. These factors should be taken into account when determining the chemical composition of the wire. This is a challenging and multifactorial task related to optimizing the chemical composition of the wire in order to ensure compliance with all of the aforementioned requirements. The formation of cold cracks in welded joints of steels that have undergone electroslag remelting can be prevented by increasing the austenitic stability of the weld metal. This can be achieved by increasing the nickel content in the welding wire. However, this results in a decrease in the resistance of the weld metal to the formation of hot cracks and a reduction in hot ductility. This makes the technology of metal rolling for wire manufacture more challenging. To enhance the resistance of the weld metal to the formation of hot cracks, it is necessary to increase the chromium content in the welding wire. However, this approach results in an increase in the ferritic phase within the weld, which subsequently leads to a reduction in the resistance of the welded joint to the formation of cold cracks. The results of the research on the effect of the chemical composition of welding wire, when varying the Cr_eq/Ni_eq ratio, on the indicators of technological strength were used to optimize the composition of the new welding wire. The experimental data on the properties of welded joints of high-strength steels made with a new welding wire demonstrated an advantage over serial joints manufactured with the Sv-08Kh20N9G7T grade wire. Furthermore, the studies of the welding aerosol showed a 6.6-fold reduction in the content of toxic manganese oxides when welding with the new wire in comparison to the conventional Sv-08Kh20N9G7T.