MECHANISM OF SURFACE QUALITY IMPROVEMENT IN CONTINUOUS CAST SLAB WITHRECTANGULAR COLD CRUCIBLE MOLD

The control of the initial stage of solidification for continuous cast ing of steel is extremely important in producing high surface quality products. The surface quality is Strongly influenced by the oscillatio n mark on the solidifying shell, which could be improved by applying a lternating electromagnetic field in the mold. A 50 x 200 mm rectangula r cold crucible mold has been designed by numerical simulation and use d for measuring the meniscus contour and local heating of molten metal s using tin and lead. It has also been used in continuous casting expe riment with Sn and Sn-10%Pb alloy to study the effects of frequency, i nput power, melt level in the mold, casting speed, mold cooling water flow rate, and mold oscillation frequency on the oscillation mark. The maximum melt temperature was observed near the triple point where the mold wall, melt free surface and the atmosphere meet all together. II has also been found that the local Joule heating density has strong i nfluence an the oscillation mark formation.