| 摘要 |
Steel products having high strength or good drawing or magnetic or electrical properties, requiring levels of carbon or manganese, or both, that are too high to allow rimming action are produced to have the desired properties, in effect, but with a surface condition characteristic of rimmed steel. The method involves pouring an ingot mold 80 to 95% full of molten, rimming steel, then allowing the steel to stand and rim for several minutes while a shell freezes against the mold wall, and thereafter filling the mold while inserting into the molten steel stream additional carbon or manganese, plus any other elements such as P, Al, Cb, V, Cr, Ni, Si or others, so that the core of the ultimately solidified ingot is steel having the above-desired strength or other properties. An integral shell or skin of rimmed steel, essentially all ferrite, covers the principal surface of the ingot, and likewise of slab, plate, and hot rolled and cold rolled strip or the like that may be derived from the ingot, thereby affording products which are in effect of the desired internal composition but have the superior surface condition of rimmed steel.
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