Investigation of the Influence of the Chemical Composition of Tubular Steels on the Features of the Formation of Phase Constituents during the Solidification of Continuously Cast Billets by Computer Simulation

Abstract

The paper presents the results of modeling the features of the formation of the main phase constituents and carbide phases during solidification and cooling of a continuously cast billet from low carbon pre-peritectic and peritectic steels used for the production of seamless pipes. As a result of calculation using the software system Fact Sage, it was found that with a carbon content in the range from 0.04% to 0.20%, and when vanadium and niobium carbide elements are introduced into the composition of carbide-forming elements of mass fraction to 0.08%, a change occurs phase composition of steels in different temperature ranges. Positive dynamics in the part of increasing the content of δ-ferrite and narrowing of the crystallization interval by transferring steel to the pre-peritectic class are noted. The temperature intervals for the separation of carbide and carbon-nitride phases in steels with different chemical compositions have been established. A comparative study of steels with manganese-vanadium / manganese-vanadium-niobium and steels with a manganese-silicon alloying system showed a significant difference in the separation of carbonitride phases in the temperature range 1200-800 ° C due to the formation of high-temperature constituents.