Abstract: A continuous casting method includes, conveying a cast slab from a casting mold, stirring a non-solidified portion in the cast slab with a first electromagnetic stirring device, stirring the non-solidified portion with a second electromagnetic stirring device disposed downstream of the first electromagnetic stirring device in a conveyance direction of the cast slab, and subsequently, rolling the cast slab with a reduction roll, in which, the first electromagnetic stirring device alternately imparts the cast slab with electromagnetic force in one direction to cause the non-solidified portion to flow toward one width direction side of the cast slab at a flow rate of at least 5 cm/s, and with electromagnetic force in another direction to cause the non-solidified portion to flow toward another width direction side of the cast slab at a flow rate of at least 5 cm/s.

Abstract: A method for producing steel includes: (a) a step of adding the first group of alloys to molten steel having an amount of dissolved oxygen of 0.0050 mass % or more; (b) a step of, after the step of (a), adding deoxidizer to the molten steel for deoxidation; (c) a step of, after the step of (b), adding the second group of alloys to the deoxidized molten steel; and (d) a step of, after the step of (c), adding REM to the molten steel, wherein amounts of oxygen Ob introduced from the first group of alloys (mass %) and amounts of oxygen Oa introduced from the second group of alloys (mass %) satisfy [Oa?0.00100], [Ob+Oa?0.00150], and [Ob/Oa?2.0], and satisfy a formula [0.05?REM/T.O?0.5] after the step of (d).

Abstract: A continuous casting method includes, conveying a cast slab from a casting mold, stirring a non-solidified portion in the cast slab with a first electromagnetic stirring device, stirring the non-solidified portion with a second electromagnetic stirring device disposed downstream of the first electromagnetic stirring device in a conveyance direction of the cast slab, and subsequently, rolling the cast slab with a reduction roll, in which, the first electromagnetic stirring device alternately imparts the cast slab with electromagnetic force in one direction to cause the non-solidified portion to flow toward one width direction side of the cast slab at a flow rate of at least 5 cm/s, and with electromagnetic force in another direction to cause the non-solidified portion to flow toward another width direction side of the cast slab at a flow rate of at least 5 cm/s.

Abstract: A continuous-cast slab is provided where central porosity is reduced by surly crushing the slab. A method and apparatus of manufacturing the slab is also provided. The continuous-cast slab having horizontally symmetrical granular equiaxed crystals at least in the center in the thickness direction includes a first reduction dent and a second reduction dent that further dents from the bottom surface of the first reduction dent and is narrower than the first reduction dent at least on one long side surface. Such a configuration can makes it possible to achieve the continuous-cast slab of no more than 2.5×10?4 cm3/g in a maximum porosity volume while segregation is reduced.

Abstract: A primary object of the present invention is to provide a continuous-cast slab where central porosity is reduced by surly crushing the slab, and a method and apparatus of manufacturing the same. The continuous-cast slab 1 having horizontally symmetrical granular equiaxed crystals at least in the center in the thickness direction includes a first reduction dent 2 and a second reduction dent 3 that further dents from the bottom surface of the first reduction dent 2 and is narrower than the first reduction dent 2 at least on one long side surface. Such a configuration can makes it possible to achieve the continuous-cast slab 1 of no more than 2.5×10?4 cm3/g in a maximum porosity volume while segregation is reduced.

Abstract: The present invention provides a continuous casting method of steel preventing alumina and other nonmetallic inclusions becoming causes of slivers and argon bubbles becoming causes of blowholes from being entrained and thereby enabling the production of a cast slab superior in surface and internal quality, that is, one giving an inside bore 21 of an immersion nozzle 21 a horizontal sectional shape of an elliptical shape or oblong shape with a length ratio DL/DS of that long axis DL and short axis DS of 1.2 to 3.8, making a direction of that long axis substantially parallel to a long side direction of the casting mold 3, and making the sliding direction of the sliding nozzle 1 a direction perpendicular to said long axis to supply the molten steel in the casting mold 3. Note that a ratio S1/S0 of a sectional area S1 at a smallest sectional area part 23 of the inside bore 21 and a sectional area S0 of a nozzle hole 11 of the sliding nozzle 1 is made 0.5 to 0.

Abstract: A steel having few alumina clusters prepared by casting liquid steel deoxidized with Al, with the addition of one or more rare-earth metals (REM) selected from the group of Ce, La, Pr and Nd in which: (a) The REM-oxide-content in oxide-based inclusions consisting mainly of alumina and REM-oxides is 0.5 to 15 mass % of said oxide-based inclusions, or (b) The mass ratio of total REM to total oxygen (T.O.), REM/T.O., in liquid steel is not less than 0.05 and not more than 0.5, in addition to (a), or (c) The total REM-content is not less than 0.1 ppm and less than 10 ppm and the dissolved-REM-content is less than 1 ppm.

Abstract: The present invention provides a continuous casting method of steel preventing alumina and other nonmetallic inclusions becoming causes of slivers and argon bubbles becoming causes of blowholes from being entrained and thereby enabling the production of a cast slab superior in surface and internal quality, that is, one giving an inside bore 21 of an immersion nozzle 21 a horizontal sectional shape of an elliptical shape or oblong shape with a length ratio DL/DS of that long axis DL and short axis DS of 1.2 to 3.8, making a direction of that long axis substantially parallel to a long side direction of the casting mold 3, and making the sliding direction of the sliding nozzle 1 a direction perpendicular to said long axis to supply the molten steel in the casting mold 3. Note that a ratio S1/S0 of a sectional area Si at a smallest sectional area part 23 of the inside bore 21 and a sectional area S0 of a nozzle hole 11 of the sliding nozzle 1 is made 0.5 to 0.

Abstract: A steel having few alumina clusters prepared by casting liquid steel deoxidized with Al, with the addition of one or more rare-earth metals (REM) selected from the group of Ce, La, Pr and Nd in which: (a) The REM-oxide-content in oxide-based inclusions consisting mainly of alumina and REM-oxides is 0.5 to 15 mass % of said oxide-based inclusions, or (b) The mass ratio of total REM to total oxygen (T.O.), REM/T.O., in liquid steel is not less than 0.05 and not more than 0.5, in addition to (a), or (c) The total REM-content is not less than 0.1 ppm and less than 10 ppm and the dissolved-REM-content is less than 1 ppm.

Abstract: A casting C obtained by solidification of molten metal by using a pair of water cooled casting rolls 2a, 2b is subjected to temperature adjustment in a temperature zone so that an austenite structure exists in its matrix. Thereafter, the casting is rolled by an in-line rolling mill 5 at a temperature ranging from 850.degree. C. to less than 1,350.degree. C. and at a reduction of 5 to 50%. In this way, overall variance of elongation of the steel material is kept within 5% in terms of the standard deviation.

Abstract: The present invention provides a thin cast strip or a thin steel sheet having good cast strip properties and mechanical properties from a molten steel containing a large amount of iron scrap containing Cu and Sn. The thin cast strip or thin steel sheet is characterized by being a thin cast strip or thin steel sheet of a common carbon steel comprising 0.15 to 10% by weight of Cu and 0.03 to 0.5% by weight of Sn, the primary dendrite spacing on a surface layer portion being in the range of from 5 to 100 .mu.m.

Abstract: An Fe-Cu alloy sheet manufactured by a thin plate continuous casting method so as to be used as a material of electronic and magnetic parts. The alloy sheet has an alloy structure of high uniformity which contains 20 to 90% Cu, 1 to 10% Cr, 0 to 10% Mo, and one or more of alloying elements selected from the group consisting of Al, Sc, Y, La, Si, Ti, Zr and Hf whose amount or total amounts are not less than a calcualtion value of the following equation and not more than 10%, the balance being essentially Fe: ##EQU1## wherein .alpha.=1,.beta.=51-(%Cu) (in the case where Cu=20 to 50%),.beta.=-19 +0.4 (% Cu) (in the case where Cu=50 to 90%).Boron and/or carbon take substantially the same effects as the above-mentioned elements such as Al.

Abstract: In a continuous casting process in a twin-roll system, a gap is provided between end faces of cooling rolls and side gates or between the circumferential surface of the cooling rolls and side faces of the side gates. A DC magnetic field is applied to the molten metal in a pouring basin in the vicinity of the side gates in a vertical direction to the molten metal and direct current (DC) is intensively fed to the end portion of the molten metal to generate an electromagnetic force mainly at a corner portion of the molten metal. The electromagnetic force is directed toward the center portion of the molten metal, and thereby prevents leakage of molten metal from the gap, penetration into the gap or the formation of hot bands. In order to intensively feed the direct current to the end portion of the molten metal, an electrode is placed in sliding contact with the end face of the cooling roll.

Abstract: A twin roll-type sheet continuous casting apparatus includes a nozzle for supplying molten metal; a pair of casting rolls for casting the molten metal supplied from the nozzle into a sheet, the casting rolls being horizontally disposed in parallel relation to each other, being cooled, and rotated in opposite directions, respectively; a coiler; and a support sheet extending generally horizontally below the pair of casting rolls for receiving the cast sheet and transferring it to the coiler, and being taken up by the coiler along with the cast sheet placed therein. Since tension is not applied to the cast sheet, even a brittle material can be continuously cast into a sheet. Also, a dummy sheet requested for starting the casting of the sheet becomes unnecessary, and even when a rupture of the sheet occurs, the apparatus can be continuously operated without stopping the operation.

Abstract: The present invention relates to a process for preparing a metal sheet having an excellent rolling property, i.e., a rollable metal sheet, which process comprises the basic steps of: continuously feeding a molten metal on a cooling material having one or two cooling surfaces being transferred and renewed for quench solidification, to thereby prepare a thin cast sheet; impinging a small rigid body particle against the surface of the resultant thin cast sheet, to work the cast sheet; heat-annealing the worked sheet in such a manner that the worked region becomes a fine recrystallized grain layer; and subjecting the cast sheet to a cold or warm rolling, optionally after a removal of oxides present on the surface; and an optional step of heat-treating the rolled sheet for working. The process of the present invention is applicable to the production of various known rollable metal or alloy sheets, such as soft steel, stainless steel, silicon steel, nickel-iron, cobalt-iron, nickel, aluminum, and copper sheets.

Abstract: A method of manufacturing an austenitic stainless steel sheet having reduced minute surface concavities and convexties ropings and gloss unevenness and a manufacturing system for carrying out the same are provided. The method comprises (a) a casting process of casting a molten austenitic (.gamma.) stainless steel into a thin cast plate by a twin-roll thin plate casting method employing a pair of cooled rolls disposed opposite to each other, (b) a cooling process of cooling the cast thin plate in a single phase state of the .gamma. phase, (c) a cast plate in a dual phase state of the .delta. and .gamma. phase or a single phase state of the .delta. phase and then cooling the thin cast plate to restore the single phase state of the .gamma. phase, and (d) a cold-rolling process of cold-rolling the heat-treated thin cast plate.

Abstract: The present invention provides a Ti--Al intermetallic compound sheet of a thickness in the range of 0.25 to 2.5 mm formed of a Ti--Al intermetallic compound of 40 to 53 atomic percent of Ti, 0.1 to 3 atomic percent of at least one of material selected from the group consisting of Cr, Mn, V and Fe, and the balance of Al, and a Ti--Al intermetallic compound sheet producing method comprising the steps of pouring a molten Ti--Al intermetallic compound of the foregoing composition into the mold of a twin drum continuous casting machine, casting and rapidly solidifying the molten Ti--Al intermetallic compound to produce a thin cast plate of a thickness in the range of 0.25 to 2.5 mm and, when necessary, subjecting the thin cast plate to annealing and HIP treating. The Ti--Al intermetallic compound sheet has excellent mechanical and surface properties.

Abstract: A continuous thin sheet of a TiAl intermetallic compound consisting of from 35 to 44 wt % Al and the balance Ti and unavoidable impurities, having a thickness of from 0.2 to 3 mm, and having a solidified, as-cast structure comprising columnar crystals extending from both surfaces of the sheet toward the center of the sheet thickness, and a process for producing the same by using a twin-roll type continuous casting procedure.

Abstract: Twin-roll type, continuous casting of metal sheets is carried out by pouring a molten metal into the clearance between a pair of rolls, provided with control plates, respectively, and rolling the poured molten metal while solidifying the poured molten metal, under a condition given by:u.gtoreq.d/awherein u is a roll surface speed (m/sec), d is a thickness of the lower edge of each of control plates (mm) and a is a coefficient depending upon the species of molten metal, thereby producing cast pieces in a sheet form.

Abstract: The present invention concerns a process for producing a grain-oriented electrical steel sheet by means of a rapid quench-solidification process, for example, a continuous casting by a twin roll strip caster. The feature of the present invention resides in quenching to solidify molten steels into a thin cast sheet of 0.7 to 3.0 mm thickness, at a cooling rate of greater than 50.degree. C./sec. in the central portion along the direction of thickness of the thin cast sheet, cooling the sheet at a cooling rate of greater than 10.degree. C./sec. in a temperature range between 1300.degree. to 900.degree. C. and then applying cold rolling for once or twice or more annealing the thin cast steel for a period between 30 seconds and 30 minutes in a temperature range between 950.degree. and 1,200.degree. C. and subsequently including intermediate annealing under a final cold rolling reduction rate of not less than 80%.