Raschetnaya otsenka rastvorimosti azota i fazovogo sostava v stali na osnove Fe-13% Cr pri ee dopolnitel'nom legirovanii (Mn, Mo, V, Nb)

Abstract

Estimates of the nitrogen solubility in model steels of various compositions based on Fe-13%Cr with additional alloying (a small amount from hundredths of a percent to 1.5%) with elements (Mn, Mo, V, Nb) that increase the solubility of nitrogen in iron-based solid solutions are calculated. 60 variants of compositions were studied. Based on previously obtained own experimental data for nitrogen-containing steels with a content of 16%Cr-5%Ni-Nb for martensitic steel, a preliminary assessment of the composition stability coefficient of nitrogen used in the calculations of its (nitrogen) solubility was carried out. The resulting value of the composition stability coefficient is lower than for austenitic steels. For steels of all composition variants with calculated nitrogen content and different content of additional alloying elements (Mn, Mo, V, Nb), the phase composition was estimated using a modified Scheffler—Delong diagram and a nonequilibrium Potak—Sagalevich diagram for steel, which processed on solid solution. It is shown, among other things, that all compositions of Fe-13%Cr-Mn, Mo, V, Nb with a low carbon content (0.03—0.05%) with the maximum calculated solubility of nitrogen in the metal are in the martensitic-ferritic region. By calculation, the temperature of the martensitic transformation beginning was obtained using the empirical Finkler—Schirra formula and a correlation was established between the temperature of the martensitic transformation beginning and the Niequivalent/Crequivalent ratio (chromium and nickel equivalents calculated using formulas for the modified Scheffler—Delong diagram).