| 摘要 |
PURPOSE: A mold flux having larger interfacial thermal resistance in the continuous casting of steel is provided to inhibit excess growth of solidification beneath meniscus, thus preventing break-out and crack of continuous casting slab. CONSTITUTION: The mold flux for continuous casting of steel comprises Na2O 10-15 wt.%, F 5-10 wt.%, CaO 25-50 wt.%, SiO2 25-40 wt.%, Al2O3 1-5 wt.% and MgO 2-7 wt.% wherein basicity(CaO/SiO2) is lower than 1.45, Na2O/F is regulated within the range of 1.0 to 2.0, and Na2O/F is regulated within the range of 1.5 to 1.7. As shown below, after mold flux is melted, molten mold flux flows into a space between solidification shell and mold and then it begins to solidify from the side contacting to the mold because surface temperature of the mold is lower than the solidification shell. As liquid glass flux(25) is transformed into crystalline mold flux layer(23), air gap(22) is formed between Cu mold(21) and crystalline mold flux layer(23) due to differential volume contraction ratio between different materials.
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