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Effect of Refractory on Nonmetallic Inclusions in Si–Mn‐Killed Steel
Author(s) -
Deng Zhiyin,
Cheng Liu,
Chen Lei,
Zhu Miaoyong
Publication year - 2019
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201900268
Subject(s) - refractory (planetary science) , materials science , spinel , metallurgy , impurity , crucible (geodemography) , chemistry , computational chemistry , organic chemistry
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.