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AssigneeRepublic Steel Corporation
InventorsClifford E. Rowden, Gregory J. McLean, Joseph E. Franklin, Dionisyj W. Demianczuk
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A rimmed steel product, in as-hot-rolled, or cold rolled and annealed form, is made essentially non-aging by inclusion of one or both of the aging-retardant elements vanadium and boron, while retaining an excellent, clear surface that is not adversely affected by the presence of such element or elements. To produce such articles, an ingot mold is poured 80 to 95% full of plain rimming steel, and the molten steel is allowed to rim, e.g. for several minutes, until a rimmed shell solidifies against the mold wall. Then pouring is completed with the same steel, while adding one or both of the aging-retardant elements to the teemed stream. Processed like rimmed steel, ultimate rolled (e.g. strip) products having a thin, truly rimmed skin over a main body of substantially non-aging steel, are found to exhibit no unwanted change of properties (e.g. as would be revealed by significant strain lines) such as usually characterizes the effect of aging in rimmed steel. There is some advantage in using the two elements together, or in the simultaneous inclusion of other, strength-promoting elements such as Cb, Zr, Si, and it has been noted that tensile properties are enhanced when V is added, as above, for aging-retardant function.
A rimmed steel product which is produced by rolling and is essentially non-aging, consisting of a skin of rimmed steel which is essentially ferrite, over the principal surface area of the product, and beneath said skin a core of substantially non-aging rimmed steel, the steel of said skin consisting essentially of 0.04 to 0.12% C, 0.2 to 0.8% Mn, and 0.035 max. % S, balance iron and incidental elements, said core consisting essentially of 0.04 to 0.12% C, 0.2 to 0.8% Mn, 0.035 max. % S, together with aging-retardant element or elements selected from the group consisting of 0.075 to 0.2% V, 0.009 to 0.04% B, or 0.03 to 0.2% V and 0.005 to 0.04% B, said core also containing one or more elements from the group consisting of 0 to 0.01% Cb, 0 to 0.15% Si, 0 to 0.01% Ti, 0 to 0.01% Zr;
A rimmed steel product which is produced by rolling and is essentially non-aging, consisting of a skin of rimmed steel which is essentially ferrite, over the principal surface area of the product, and beneath said skin a core of substantially non-aging rimmed steel, the steel of said skin consisting essentially of 0.05 to 0.12% C, 0.2 to 0.8% Mn, and 0.035 max. % S, balance iron and incidental elements, said core consisting essentially of 0.05 to 0.12% C, 0.2 to 0.8% Mn, 0.035 max. % S, together with aging-retardant element or elements selected from the group consisting of 0.075 to 0.2% V, 0.009 to 0.04% B or 0.03 to 0.2% V and 0.005 to 0.04% B.
A method of making an essentially non-aging, rolled product of rimmed steel, comprising pouring an ingot mold 80% to 95% full of molten steel consisting essentially of 0.04 to 0.12% C, 0.2 to 0.8% Mn, 0.035 max. % S, balance iron and incidental elements, allowing said filling to undergo rimming action while a shell of rimmed steel solidifies next to the mold surrounding a still-molten core, and then completing pouring of said molten steel into said ingot mold while adding to the molten steel in the mold, sufficient material to provide in the finished core:
Dependencies are inferred from the claim text.