Kabushiki Kaisha Kobe Seiko Sho

Kobe Steel, Ltd.

Takasuke Mori

Kiichi Narita

Kenzo Ayata

Takahiko Fujimoto

Jun Miyazaki

Hitoshi Nakata

Takamichi Ito

Chisato Yoshida

Manabu Miyamoto

Takehisa Makino

A method for the continuous production of cast steel strands which are 200 mm.times.200 mm or less in cross-section by a continuous casting process in which molten steel containing over 0.20% of carbon is fed into a casting mold with a lubricant through a submerged nozzle or in an open stream and continuously drawn out downwardly of the casting mold, which includes the steps of (a) electromagetically stirring the molten steel at a position within said casting mold by the application of a magnetic field induced by introducing into an electromagnetic coil an alternating current of a frequency (f) in the range of 1.5 to 15 and maintaining the magnetic flux density (gauss) in the range of 602 e.sup.-0.10f to 1844 e.sup.-0.12f at the center of the electromagnetic coil, and (b) electromagnetically stirring the molten steel at a position in the final solidifying zone, of the continuously cast strand, in which the shorter diameter of the molten steel pool is smaller than 1/2 the length of the shorter side of the cast strand, by the application of a magnetic field induced by introduing an alternating current into an electromagnetic coil and maintaining the magnetic flux density (gauss) in the range of 0.143.multidot.D.sup.2 +231 to 0.343.multidot.D.sup.2 +451 at the center of the electromagnetic coil, wherein D is the solidified shell thickness in millimeters of the continuously cast strand, the value of the D ranging from 20 to 90, thereby permitting the production of medium and high carbon killed steel billets, which are improved as to segregations, inclusions, surface quality, cold forgeability, and machinability, by a continuous casting process at low cost.

Method for the continuous production of cast steel strands

A method for the continuous production of cast steel strands which are 200 mm.times.200 mm or less in cross-section by a continuous casting process in which molten steel containing 0.20% or less of carbon is fed into a casting mold with a lubricant through a submerged nozzle or in an open stream and continuously drawn out downwardly of the casting mold. The method includes the steps of (a) electromagnetically stirring the molten steel at a position within said casting mold by the application of a magnetic field induced by introducing into an electromagnetic coil an alternating current of a frequency (f) in the range of 1.5 to 15 hertz and maintaining the magnetic flux density (Gaub) in the range of 602e.sup.-0.10f to 2441e.sup.-0.11f at the center of the electromagnetic coil, and (b) electromagnetically stirring the molten steel at a position in the final solidifying zone, of said continuously cast strand, in which the shorter diameter of the molten steel pool is smaller than 1/2 the length of the shorter side of the cast strand, by the application of a magnetic field induced by introducing an alternating current into an electromagnetic coil and maintaining the magnetic flux density (Gaub) in the range of 0.2.multidot.D.sup.2 +280 to 0.343.multidot.D.sup.2 +451 at the center of the electromagnetic coil, wherein D is the solidified shell thickness in millimeters of said continuously cast strand, the value of D ranging from 20 to 90. The method thereby permits the production of low carbon killed steel billets which are improved as to negative segregations, center cavities, inclusions, surface quality, cold forgeability, and machinability, by a continuous casting process at low cost.

A device for electromagnetically regulating the pouring rate in continuous casting, including a cylindrical molten steel container having a molten steel inlet formed in a peripheral section of an upper surface thereof and a molten steel outlet formed in central section of a lower surface thereof to pour the molten steel into a mold, and electromagnetic coils disposed around the side wall of the molten steel container so as to generate a rotating magnetic field perpendicularly to the side wall. The pouring rate is determined by the interactive function of the head of the molten steel in the tundish disposed above the molten steel container with the outlet thereof joined to the inlet of the molten steel container, the intensity of the rotating magnetic field, namely, the magnitude of the electric current supplied to the electromagnetic coils, and the size of the molten steel outlet, namely, a replaceable pouring nozzle.

Method and device for electromagnetically regulating pouring rate in

A feed nozzle unit for a horizontal continuous casting process, the feed nozzle unit being disposed in coaxial relation between a tundish nozzle and a mold in a horizontal continuous casting device and including a fixing member of cylindrical form fixedly connected to the mold, the feed nozzle being fixed and connected in coaxial relation to the fixing member at a position inside a connecting side of the tundish nozzle, and the connecting refractory material being fitted in coaxial relation to the fixing member at a position adjacent a connecting side of the mold.

Structure of feed nozzle unit for horizontal continuous casting process

A method of treating a continuous cast strand in a horizontal continuous casting process wherein when the level of molten steel within a tundish becomes lower than a prescribed level at a portion near the upper surface of a tundish nozzle at final stage of the casting process, drawing of the continuous cast strand is discontinued, and after a lapse of a specified time the drawing of the continuous cast strand is again performed and the strand is broken at the feed nozzle.

Method of treating final continuous cast strand in a horizontal

A horizontal continuous casting process wherein at least two electromagnetic stirring devices of a rotary magnetic field type are arranged in series direction whereby electromagnetic stirring force acts on non-solidified molten metal, and the distance between the electromagnetic stirring devices of first and second stages is set to specified relation.

Electromagnetic stirring method in horizontal continuous casting process

An electromagnetic within-mold stirring method and apparatus wherein electromagnetic stirring is imparted to molten steel passing through a mold, under the following conditions where the maximum flux density (in gauss) of a magnetic field induced by an electro-magnetic coil ranges from 1045.e.sup.-0.16f to 2054.e.sup.-0.12f (f: frequency, 1-15 Hz) and the place of the maximum magnetic flux density is within the range of 350 mm from the junction between the pouring nozzle and the mold in the direction of drawing of the cast-piece.

Electromagnetic within-mold stirring method of horizontal continuous

A continuous steel casting process adapted to produce steel castings of satisfactory quality with less center segregations is described. A molten steel is electromagnetically stirred in at least two of three locations, viz., a casting mold and intermediate and final solidifying zones of a continuously cast strand. In the casting mold, is applied a magnetic field induced by alternate current of a frequency f=1.5.about.10 Hz and having G in the range of 195.times.e.sup.-0.18f .about.1790.times.e.sup.-0.2f at the inner surface of the casting mold. The intermediate solidifying zone employs a magnetic field induced by alternate current of a frequency f=1.5.about.10 Hz and having a magnetic flux density G in the range of 195.times.e.sup.-0.18f .about.1790.times.e.sup.-0.2f at the surface of the strand or a magnetic field induced by alternate current of a frequency f=50.about.60 Hz and having a magnetic flux density G in the range of 0.6.times.10.sup.6 /(D-107).sup.2 .about.1.8.times.10.sup.6 /(D-100).sup.2 (in which D=the thickness of a solidified shell layer of the strand) at the surface of the strand. For electromagnetic stirring in the final solidifying zone, a magnetic field induced by alternate current of a frequency f=1.5.about.10 Hz and having a magnetic flux density in the range of 895.times.e.sup.-0.2f .about.2137.times.e.sup.-0.2f is applied.

Continuous steel casting process

A method for treating molten steel utilizing an induction coil, a ladle, a treating vessel and at least one passage pipe interconnecting the ladle and the treating vessel which includes the steps of lifting up a part of the molten steel from the ladle to the treating vessel disposed over the ladle through adjustment of molten steel composition and/or degassing in the treating vessel, thereafter returning the molten steel to the ladle through the at least one passage pipe, circulating or reciprocating the molten steel between the ladle and the treating vessel while heating the molten steel by the induction coil disposed around the at least one passage pipe and operating the linear motor at a frequency of 50 to 60 cycles.

Method for treating molten steel and apparatus therefor

A method of agitating a bath of melted metal for treating the same by blowing gas into a one piece columnar body of such melted metal disposed in the bath to cause the apparent specific gravity of the columnar body to be reduced and to thereby be hydrostatically lifted, and returning the lifted portion of the melted metal to the bath by pouring the same with a splashing effect onto the free surface of the bath, in a manner to continuously change the pouring position on the free surface of the bath, thereby causing improved agitation of the bath, and especially improved contact and mixing of the melted metal and a treating agent generally floating on the free surface of the bath.

Method of and an apparatus for agitating a bath of melted metal for

A method of agitating a bath of melted metal for treating the same by blowing gas into a columnar body of such melted metal disposed in the bath to cause the apparent specific gravity of the columnar body to be reduced and to thereby be hydrostatically lifted, and returning the lifted portion of the melted metal to the bath by pouring the same with a splashing effect onto the free surface of the bath, in a manner to continuously change the pouring position on the free surface of the bath, thereby causing improved agitation of the bath, and especially improved contact and mixing of the melted metal and a treating agent generally floating on the free surface of the bath.

Method for agitating a bath of melted metal for treating the same

Lamellar graphite-containing iron based and nickel based alloys are prepared by unidirectionally solidifying an iron base or nickel base alloy having a carbon content of 2 to 5% at a solidification rate not greater than 10 mm/hr and subjecting the solidified alloy to a hot plastic deformation processing in a direction parallel to the solidification direction.

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Ashiya, Japan

Takasuke Mori