Investigation of Silicon and Manganese Solubility in Cementite of Iron-Based Alloys

Abstract

In the paper we obtained the expression of cementite free energy and determined the solubility of manganese and silicon in Fe3C cementite depending on the temperature. Investigation was carried out for alloys with carbon content of 0.55-0.60 % (wt.), silicon content of 0.95-1.0 % (wt.), manganese content of 0.8-0.9% (wt.), the rest was iron. The smelting of Fe-Mn-Si-C system alloys was carried out in the alundum crucible furnace in argon atmosphere. The cooling rate of alloys after casting was 10 K/s. Microstructure analysis along with X-ray diffraction analysis was used to determine the structural state of the alloys. In addition, the physical characteristics of the alloys studied in this paper were determined, such as alloy chemical dependence of ultimate strength, extension and contraction ratio, impact toughness and hardness. The results obtained in this paper showed that the iron-based alloy with the content of carbon of 0.57 % (wt.), silicon of 0.97 % (wt.) and manganese of 0.85 % (wt.)) had the superior microstructure and physical properties. The microstructure of alloys studied in the paper is represented by pearlite, which makes up to 95 % of the volume. In the alloys we revealed the highly dispersed inclusions of Fe2.7Mn0.3C, Fe0.25Mn1.4C0.6 and Fe9SiC0.4 carbides, whose volume ratio was up to 1.5 %, the rest was ferrite. As it is known, the structural constituent of pearlite is cementite. The cementite has a significant effect on the physical properties of alloys. Application of quasi-chemical method enables to calculate the free energy of silicon and manganese doped with cementite and to determine the temperature dependence of silicon and manganese content in cementite. It is ascertained that there is a slight increase of carbon content in cementite (up to 28.79 % (atoms). Manganese can replace up to 12 % of iron atoms, and silicon can replace up to 4.5 % of iron atoms, depending on temperature. The calculated data obtained in this paper are in good agreement with those found experimentally by other authors.

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

“…(в зразку криці № 3 у порівнянні зі зразком криці № 1) приводить до збільшення кількости включень -складних карбідів і силіцидів Феруму. Одержаний результат можна пояснити тим, що є межа розчинности елементів у фазах, а їхній надлишок приводить до утворення окремих включень [14][15][16].…”

“…З літературних джерел відомо, що Манґан стабілізує аустеніт [14] і зменшує дифузійну рухливість Карбону в аустеніті та схильний, так само, як і Силіцій, до макросеґреґації [7,17]. Дендрити зразків з кіркової зони криці № 3 мали вміст Манґану у 0,2% (мас.…”

“…де õ1С, õ1Fe, x1Si та x1Mn -концентрації відповідних хемічних елементів у δ-фериті [14], а L 1 ij -енергія парної взаємодії компонентів, L 1 ijz -енергія взаємодії трьох компонентів, L 1 ijzk -енергія взаємодії чотирьох компонентів (Дж/моль).…”

Microstructure, Nano-, and Macro-Indentation Characterization of AISI 302 Steel After High-Temperatures Aging

“…Owing to their importance at the industrial level, steels have been extensively studied to understand their metallurgical behavior [5][6][7][8][9][10]. In the literature, the phenomenon of austenite grain growth and its relationship with the temperature and time of the aging treatment have gained great interest [11][12][13].…”