Metallurgical and Materials Transactions B

, Volume 47, Issue 2, pp 1217–1227 | Cite as

Formation Mechanism of CaS-Al2O3 Inclusions in Low Sulfur Al-Killed Steel After Calcium Treatment

  • Jianfei Xu
  • Fuxiang Huang
  • Xinhua Wang


The laboratory experiments of alumina inclusions modified by calcium treatment in Al-killed steel were carried out at 1873 K (1600 °C), and the inclusions in steel samples were characterized at 1, 5, and 10 minutes after calcium addition. The results show that the type of inclusions after calcium treatment was determined by the sulfur and T.O contents of steel. CaS-Al2O3 inclusions were obtained in steels with high sulfur and low T.O contents. The mass ratio between CaS and Al2O3 was determined by T.Ca and T.O contents of steel. The influence of holding time after calcium addition on the composition of inclusions was negligible. The thermodynamics for the formation of CaS-Al2O3 inclusions after calcium treatment was discussed, and a simple formation mechanism was proposed. Moreover, the CaO, Al2O3, and CaS contents in the inclusions were predicted through the sulfur, total calcium (T.Ca), and T.O contents, and it was found that the CaO content decreases with increasing S/T.O, while (pctCaS)/(pctAl2O3)1/3 increases with increasing T.Ca/T.O.


Sulfur Content Steel Sample Molten Steel Calcium Aluminate High Sulfur Content 
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Copyright information

© The Minerals, Metals & Materials Society and ASM International 2016

Authors and Affiliations

  1. 1.School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijingP.R. China

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