| 摘要 |
PURPOSE:To prevent longitudinal crack of solidified shell at initial stage in kind of steel executing hypo-peritectic solidification having 0.10-0.15% carbon content by arranging the specific lattice-like grooves on mold surface positioning near meniscus of molten steel. CONSTITUTION:In the copper-made mold for continuous casting, on the mold surface positioning gear the meniscus of the molten steel in the mold, the lattice- like grooves having 0.5-1.0mm depth and 0.5-1.0mm width are arranged at 5-10mm interval between the grooves. By this method, cooling degrees at grooving part and non-grooving part fiffer and the initial solidification is a little delayed at the grooving part, which is weak cooling part. Therefore, the liquid phase is remained at every fixed intervals and absorbs strain at the time of shrinking, and bending of the solidified shell at the initial stage is restrained and the solidified shell is locally separated from the mold. Therefore, heat conduction is made uniform and the solidified shell thickness is made uniform. In this result, as the local thin part in the solidified shell layer is eliminated by developing the solidified shrinkage and transformation stress at the time of transforming delta gamma, the stress is not concentrated at one point. |
