Basic Physicochemical Concepts for Controlling the δ-Ferrite Content When Welding with Austenite-Ferrite Materials

Abstract

Abstract—By the example of the metal of a seam obtained using welding materials based on 10Kh19N11M4F steel which are currently used for the welding of high-strength low-alloy steels, the influence of its chemical composition on the behavior of δ-ferrite throughout the entire temperature range of its existence is shown. On the basis of these studies, the prospects of the use of 10Kh19N11M4F steel for the welding of high-nitrogen corrosion-resistant steels with the retention of their nonmagnetization, including in the area of the welded joint, are shown. The critical parameters determining the behavior of δ-ferrite upon crystallization and subsequent cooling of solid steel are found using thermodynamic modeling. It is shown that the depth of the σ-ferritic transformation and the maximum equilibrium temperature of austenitization used for the interpretation of the experimental data obtained during hot physical modeling of welding are the most important among them. The areas of promising compositions of the metal of the seam in the case of welding of low-alloy high-strength and high-nitrogen corrosion-resistant steels without hot cracks and providing, if necessary, nonmagnetization of the seam are found and depicted on the fragment of the improved Scheffler–Speidel diagram.