Study of High-Strength Austenitic Nitrogen-Containing Steel Ingot Phase Formation and Structure

Abstract

Thermodynamic modeling is performed for phase formation of nitrogen-containing steel 04Kh20N6G11M2AFB during crystallization, solidification, and cooling that shows crystallization proceeds through δ-ferrite. In this case depending on alloying element content within the limits of the grade composition δ-ferrite may exist both at temperatures corresponding to the cuidus — solidus interval, and also be retained below the solidus temperature. Ingot metal is examined comprehensively in different ingot zones in order to study structure formation throughout the ingot volume, alloying element liquation, and nonmetallic inclusion and secondary phase composition and distribution.