Reaction Behaviors of Al-Killed Medium-Manganese Steel with Different Refractories

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Some laboratory experiments are carried out to investigate the reaction between manganese steel and ladle slag. It is found that as expected when the slag basicity [R = w(CaO)/w(SiO2)] is sufficiently low, for example, R < 4, the dissolved Al in conventional Al‐killed steel could reduce the SiO2 component of the slag. In the case of manganese steel grades [w(Mn): 6–20%, w(Al): 0.025%], the reduction of SiO2 by dissolved Mn becomes much more profound compared with that by dissolved Al, resulting in the increase of MnO in slag. When the Mn content is high enough, for example, w(Mn) = 20%, the reaction between the MgO in slag and the dissolved Mn in steel is also very evident. High slag basicity can restrain the reduction of SiO2 by dissolved Mn, but the reaction between MgO and Mn can still take place to generate MnO in slag. High‐basicity refining slag (R > 4) is recommended for manganese steel grades.

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confidence: 81%

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confidence: 74%

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confidence: 50%

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confidence: 77%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Reaction of Al‐Killed Manganese Steel with Ladle Slag

Deng

Kong

Dong

et al. 2019

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Effect of Refractory on Nonmetallic Inclusions in Si–Mn‐Killed Steel

Deng

Liu

Chen

et al. 2019

Self Cite

Some laboratory experiments are carried out to study the effect of different refractories on the original and exogenous inclusions in Si-Mn-killed steel. As expected, it is found that Al 2 O 3 refractory causes high melting points of both SiO 2 -Al 2 O 3 -MnO system and SiO 2 -Al 2 O 3 -CaO system inclusions, while MgO crucible reduces the melting points of both systems of inclusions to a certain extent. The purity of MgO refractory is crucial for tire cord steel grades, and even 0.3% of Al 2 O 3 impurity in refractory results in an evident increase (by 10%-20%) of Al 2 O 3 content in the inclusions. Similar to Al-killed steel grades, MgO·Al 2 O 3 spinel can also be stable in Si-Mn-killed steel due to the effect of MgO refractory, and MgO and Al 2 O 3 inclusions can transform into MgO·Al 2 O 3 spinel. These inclusions should be strictly controlled during refining process. High-purity and high-quality MgO refractory as well as high-quality alloys are recommended for Si-Mn-killed steel grades, and Al 2 O 3 -based refractory should be avoided.

Effect of MgO on Evolution of Interface Structure between Low‐Basicity Refining Slag and MgO–C Refractory

Yu,

Li,

Zeng

et al. 2023

MgO–C bricks are widely used as a refractory lining in the slag line part of the ladle of a cord steel refining. The dissolution of their main component MgO into the refining slag is one of the main reasons for their shortened service durability. Laboratory experiments are carried out using low‐alkalinity refining slag and unaltered MgO–C bricks by static crucible method. Physicochemical analysis, FactSage thermodynamic calculations, etc., are performed on the specimens, and the dissolution mechanism of magnesia is investigated. When the low‐melting‐point‐phase CaMgSiO4 (CMS) decomposes at high temperatures, the concentration and activity of (MgO) at the local interface between slag and MgO‐C brick increase rapidly, inhibiting the dissolution of magnesia into slag at the CMS in situ. The rapid weakening of the dissolution drive of the slag to the magnesia corrosion occurs when the MgO content in the refining slag approaches saturation. To verify the feasibility of extending the service life of MgO–C bricks at the refining ladle slag line, the study involves controlling the MgO content in the refining slag.