Effect of slag composition on the cleanliness of 28MnCr5 gear steel in the refining processes

Dong, Wenliang; Ni, Hongwei; Zhang, Hua; Lü, Ze-an

doi:10.1007/s12613-016-1235-y

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…The average %CaO/%Al 2 O 3 ratio is slightly higher for B slag (6.25) than for A slag (5.0), so the CaO supply for the transformation of the inclusions towards the liquid region is favored for slag B 39,[40][41][42] . In general, it is concluded that Al 2 O 3 inclusions are formed as a result of re-oxidation by air (the effect of the oxidation degree in slag is smaller) and the decrease in temperature during the final step of the steel manufacturing process 9,27,43 . On the other hand, the formation of inclusions of pure spinel (MgO⋅Al 2 O 3 ) is facilitated due to an increase in slag fluidity, which leads to increased MgO erosion of slag line refractories, as well as MgO saturation, which increase the dissolved magnesium in the liquid steel 1,9,10,17,18,[44][45][46][47][48] .…”

Section: Inclusionary Analysismentioning

confidence: 99%

“…Yoon et al 5 determined the optimized ratio (%CaO/%Al 2 O 3 ) for bearing steels in the slag between 1.7 and 1.8 by the addition of Al 2 O 3 and reduction of the CaO, changing the slag to the composition of slags found in a region of low melting temperature. Dong et al 27 reports that a %CaO/%Al 2 O 3 > 2 ratio in slag increases total oxygen, decreasing the ability of slag to absorb oxide inclusions and facilitating high melt temperature inclusions in high ratios.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Secondary Refining Slag Parameters with Focus on Inclusion Cleanliness

et al. 2018

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Secondary refining slag samples with different chemical compositions (45-54 % CaO, 7-13 % Al 2 O 3 , 20-29 % SiO 2 , 9-16 % MgO, 0-5 % CaF 2) were investigated to verify the influence of their effective viscosity on inclusion cleanliness of DIN 38MnS6 in a steelmaking plant. The steel samples were collected during the production process for analysis of inclusions. Using the commercial software FactSage 6.4, thermodynamic calculations were performed to determine the effective viscosity, solid fraction, liquid fraction and MgO saturation point of these slags at 1560ºC. The results showed that all the slags were saturated in MgO, revealing a better protection of the ladle refractory. The addition of 2 to 5 % of CaF 2 reduced the effective viscosity values for the analyzed slags from 0.45 Pa•s to 0.10 Pa•s , in comparison to the slags without the addition of CaF 2 , with an effective viscosity of 0.40 Pa•s, 0.27 Pa•s and 0.22 Pa•s, decreasing the level of non-metallic inclusions for some of the analysed heats. However, it was detected during the manufacturing process that high slag fluidity and re-oxidation events continue to be a challenge associated with reducing the level of non-metallic inclusions.

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Section: Inclusionary Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of Secondary Refining Slag Parameters with Focus on Inclusion Cleanliness

et al. 2018

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“…Hence, the type and composition of the inclusions are important to pipeline steels which should be well controlled. Inclusions are usually controlled by adjusting compositions of slag or/and steel during steelmaking process [16][17][18][19][20][21]. In addition, the nonmetallic inclusions can transform even during and after solidification.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cooling Rate on the Formation of Nonmetallic Inclusions in X80 Pipeline Steel

Zhang

Yang

et al. 2019

Metals

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Nonmetallic inclusions have a strong influence on the hydrogen-induced cracking (HIC) and sulfide stress cracking (SSC) in pipeline steels, which should be well controlled to improve the steel resistance to HIC and SSC. The effects of cooling rate on the formation of nonmetallic inclusions have been studied both experimentally and thermodynamically. It was found that the increasing cooling rate increased the number density and decreased the size of the inclusions, while the inverse results were obtained by decreasing the cooling rate. Furthermore, as the cooling rate decreased from 10 to 0.035 K/s, the inclusions were changed from Al2O3-CaO to Al2O3-CaO-MgO-CaS. At a high cooling rate, the reaction time is short and the inclusions cannot be completely transformed which should be mainly formed at high temperatures. While, at low cooling rate, the inclusions can be gradually transformed and tend to follow the equilibrium compositions.

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Formation of Plastic Inclusions in U71Mnk High-Speed Heavy-Rail Steel Refined by CaO-SiO2-Al2O3-MgO Slag

Zhang

Liu

Lin³

et al. 2018

Metall Mater Trans B

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Effect of slag composition on the cleanliness of 28MnCr5 gear steel in the refining processes

Cited by 4 publications

References 12 publications

Analysis of Secondary Refining Slag Parameters with Focus on Inclusion Cleanliness

Analysis of Secondary Refining Slag Parameters with Focus on Inclusion Cleanliness

Effect of Cooling Rate on the Formation of Nonmetallic Inclusions in X80 Pipeline Steel

Formation of Plastic Inclusions in U71Mnk High-Speed Heavy-Rail Steel Refined by CaO-SiO2-Al2O3-MgO Slag

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