Influence of the Carbon, Manganese, and Silicon Content on Formation of Structural Components During Continuous Casting of Steels

Abstract

Манґану та Силіцію: в кірковій зоні та на 1/2 радіюса злитку сеґреґацію Манґану до 0,7% (мас.) і Силіцію до 0,5% (мас.), а в центральній частині злитку вміст буде майже таким, як їхній вміст у стопі.Ключові слова: безперервно литі криці, дендрити заліза, сеґреґація Манґану та Силіцію.The study of continuously cast steels with different contents of carbon, manganese and silicon is carried out in the work. To determine the features of the structural state of steels, we use microstructural analysis, x-ray microanalysis, and x-ray diffraction method. As shown, depending on the carbon, manganese, and silicon contents in the structure during solidification, the next development is possible as follows: formation of the primary phase of δferrite and, then, formation of γ-iron according the peritectic reaction; coexistence of L-, γand δ-phases, and formation of γ-iron from the melt. As found, with an increase in the carbon content ≥ 0.5 wt.%, manganese content ≥ 0.75 wt.% and silicon content ≥ 0.45 wt.% in steel, formation of the δferrite primary phase from the melt in the continuous cast steel billet does not occur. At given content of carbon, manganese and silicon in the steel, formation of γ-iron in the melt and increase in the quantity of inclusions, namely, complex carbides and iron silicides, are observed. Calculations show that, with an increase in the manganese and silicon contents, the peritectic area in the diagram decreases. In the interdendritic space, the segregation of manganese and silicon is detected: in the crust zone and at the 1/2 radius of ingot, the segregation of manganese is up to 0.7 wt.% and the silicon one is up to 0.5 wt.%; in the central part of ingot, the content will be almost the same as in the alloy.