Study on the modification of inclusions by Ca treatment in GCr18Mo bearing steel
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The effect of Ca treatment on the modification of inclusions in Al-killed GCr18Mo bearing steel was studied and a thermodynamic and kinetic model was established. The experimental results showed that oxygen content in the steel could be reduced from 120 μg/g to the range 5.5–21.6 μg/g by Al-Ca complex deoxidization at 1 873 K. An appropriate increase in Ca/Al mass ratio is beneficial to reduce the total oxygen content in steel. When the content of dissolved aluminum was in the range of 0.03%–0.3%, with the increase of Ca/Al mass ratio from 0.8–1.6 to 2.4–3.2, the number of inclusions per unit area significantly reduced. In addition, the main types of inclusions were modified from large-sized Al2O3 clusters to plastic or semi-plastic liquid phase calcium aluminates. The experimental results matched well with the thermodynamic analysis.
KeywordsGCr18Mo bearing steel Ca treatment Inclusion modification Deoxidization Thermodynamics
This study was financially supported by the Shanghai University and the Joint Funds of the National Natural Science Foundation of China (Grant No. U1560202).
- 3.Verma N (2010) Modification of spinel inclusions by calcium in liquid steel. Iron Steel Technol 7(1):189–197Google Scholar
- 7.Huang XH (1981) Principles of iron and steel metallurgy. Metallurgical Industry Press, BeijingGoogle Scholar
- 11.Chen JX (2010) Commonly used chart data handbook for steelmaking. Metallurgical Industry Press, BeijingGoogle Scholar
- 15.Won-Gap S, Han WH, Jeong-Sik K et al (2007) Deoxidation equilibria among Mg, Al and O in liquid iron in the presence of MgO·Al2O3 spinel. ISIJ Int 43(2):201–208Google Scholar
- 17.Murray JD, Johnson RF (1963) Effect of inclusions on the properties of 1%C-Cr bearing steels. J Iron Steel Inst London Spec Rep No 77: 104–109Google Scholar
- 18.Ning M, Fu JC, Zheng JH (2005) Study on inclusions modification in steel by weeding Ca-Si wire (Ca-treatment). In: CSM 2005 annual meeting proceedings, pp 246–251Google Scholar