Analysis of non-metallic inclusions in low-alloy steels
Keywords:
Low-alloy steel, non-metallic inclusions, metallographic analysis, micro-X-ray spectral analysis, calcium aluminates, magnesium spinel, oxide-sulfide phases, deoxidation, morphology, phase compositionAbstract
This paper investigates the morphological, chemical, and phase composition of non-metallic inclusions in low-alloy steel. A comparative analysis was carried out for steel samples produced using conventional and proposed technologies. The amount, size, shape, and morphological characteristics of non-metallic inclusions were evaluated by metallographic analysis, while their elemental composition was determined using micro-X-ray spectral analysis. The results showed that the non-metallic inclusions in the investigated steel are mainly represented by complex oxide-sulfide phases belonging to the Ca–Al–Mg–O–S system. Calcium aluminates constitute the major part of the inclusions, while MgO·Al₂O₃-type magnesium spinel and sulfide phases such as CaS and MnS were also identified. A relationship between the morphology and phase composition of the inclusions was established, and their influence on the behavior of inclusions during hot deformation was evaluated. Based on the experimental results and thermodynamic calculations, a technological approach aimed at promoting the formation of 3CaO·Al₂O₃-type calcium aluminates was proposed to control the phase composition of non-metallic inclusions. The obtained results provide a scientific basis for improving steel deoxidation and modification processes and for targeted control of the size, morphology, and phase composition of non-metallic inclusions
References
EEIMVR-UFF, V. R. (2019). The effects of non-metallic inclusions on properties relevant to the performance of steel in structural and mechanical applications. J Mater Res Technol, 8(2), 2408.
Liu, H., Zhang, S., Zhang, J., Ren, Q., Zhang, L., & Ge, Y. (2023). Properties of typical non-metallic inclusions in steel: First-principles calculations. Materials Today Communications, 34, 105118.
Zhang, L., & Ren, Y. (2025). Handbook of non-metallic inclusions in steels. Springer Nature.
Kholmirzaev, N., Turakhodjaev, N., Khasanov, J., Bektemirov, A., Saidmakhamadov, N., Nurdinov, Z., … Khasanov, K. (2026). Thermodynamic mechanism of non-metallic inclusions modification in recycled low-alloyed cast steel using CaCO₃–CaSiO₃ composite mineral fluxes. Acta Metallurgica Slovaca, 32(3), 241–250.
Kholmirzaev, N., Turakhodjaev, N., Khasanov, J., Yang, C., Yusupov, B., Saidkhodjaeva, S., ... & Nurmurodov, B. (2026). Formation and characterization of non-metallic inclusions in steel produced by melting secondary ferrous scrap in an electric arc furnace: A case study of AISI 1066 steel. Acta Metallurgica Slovaca, 32(2), 116-123.
Turakhodjaev, N., Kholmirzaev, N., Nargiza, S., Kamola, T., & Abdullayev, B. (2022). Technology for cleaning non-metallic inclusions and gaseous pores in the process of liquefaction of steels in an electric arc furnace. European Multidisciplinary Journal of Modern Science, 4, 77-82.
Saidmakhamadov, N., Kholmirzaev, N., Bekchanova, V., Odilov, F., Karimov, B., Tadjiev, N., ... & Mukhammadaliev, B. (2026, March). Analysis of technologies for improving steel purity by controlling slag content. In AIP Conference Proceedings (Vol. 3390, No. 1, p. 020014). AIP Publishing LLC.
Peela, A., Mikitisin, A., Steinweg, F., Janitzky, T., Schwedt, A., Broeckmann, C., & Mayer, J. (2025). Influence of subsurface non-metallic inclusions on rolling contact fatigue behavior in bearing steels - Experimental and numerical investigations. Wear, 566–567. https://doi.org/10.1016/j.wear.2025.205767
Wang, J., Guo, B., Lyu, B., & Zhang, L. (2024). Thermodynamic modelling on the reaction between steel and slag. Journal of Materials Research and Technology, 32. https://doi.org/10.1016/j.jmrt.2024.08.005
Calderon Hurtado, F. A., Govro, J., Emdadi, A., & O’Malley, R. J. (2024). The Melting Behavior of Hydrogen Direct Reduced Iron in Molten Steel and Slag: An Integrated Computational and Experimental Study. Metals, 14(7). https://doi.org/10.3390/met14070821
Luiz, A., & Costa e Silva, V. (2018). Non-metallic inclusions in steels—Origin and control. J. Mater. Res. Technol, 7(3), 283-299.
Ren, Y., Wang, W., Yang, W., & Zhang, L. (2023). Modification of non-metallic inclusions in steel by calcium treatment: a review. ISIJ International, 63(12), 1927-1940.
Babu, S. R., & Michelic, S. K. (2024). Overview of application of automated SEM/EDS measurements for inclusion characterization in steelmaking. MetalMat, 1(2), e18
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