Jfe Steel Corporation

Kawasaki Steel Corporation

Yuji Miki

Norichika Aramaki

Naoki Kikuchi

Yukio Takahashi

Shuji Takeuchi

Kenichi Sorimachi

Nagayasu Bessho

Toshikazu Sakuraya

Goro Okuyama

Hidenari Kitaoka

Shingo Sato

Tetsuya Fujii

Hiroyuki Ohno

Shota Amano

Yasuo Kishimoto

Yuichi Uchida

Seiji Itoyama

Yusuke Vincent Fujii

Yoshiyasu Kawasaki

Osamu Furukimi

Hiroyuki Ono

Masayuki Onishi

Akio Tosaka

Hideo Kuguminato

Tomohiro Tanaka

Toru Inoue

Seiji Nabeshima

Nobuhiko Oda

Fumio Sudo

Sumio Yamada

Saburo Moriwaki

Hirokazu Tozawa

Akitoshi Matsui

Kohei Furumai

Kenji Nakase

Hiroshi Yamane

Takeshi Murai

Keigo Toishi

Naomichi Iwata

Tadasu Kirihara

Makoto Aratani

Hiroshi Nomura

Chikashi Tada

Shigeru Ogura

Tomoharu Ishida

Noboru Yasukawa

Yoshie Nakai

Shinichi Nagai

Akira Yamauchi

Masatoshi Aratani

Yoshiro Tomiyama

Kenji Tsuzumi

Yuki Nabeshima

Tomoya Odagaki

Naoya Shibuta

Takahiko Maeda

Yukio Usui

Masanori Nishikori

Mitsuru Sakurai

Yuta Hino

Seiji Nabesima

Shunichi Kawanami

Yuko Takeuchi, Legal Representative

Yoichi Itoh

Tsukasa Terashima

Yasutaka Ta

Yozo Tanino

Ryosuke Chiyohara

Masayuki Mitsuzono

Toshinori Tawa

Toru Ikagawa

Continuous casting mold is provided having a mold copper plate having plural separate portions filled with foreign metal formed by filling concave grooves formed on the inner wall surface of the mold copper plate and having a diameter of 2 mm to 20 mm in the inner wall surface at least in the region from a meniscus to a position located 20 mm or more lower than the meniscus with the foreign metal whose thermal conductivity is 80% or less or 125% or more of the mold copper plate, the ratio of the Vickers hardness HVc of the mold copper plate to the Vickers hardness HVm of the filling metal satisfies expression (1), and the ratio of the thermal expansion coefficient &#x3b1;c of the mold copper plate and the thermal expansion coefficient &#x3b1;m of the filling metal satisfies expression (2).0.3&#x2264;HV/HV&#x2264;2.3&#x2003;&#x2003;(1),0.7&#x2264;&#x3b1;&#x2264;3.5&#x2003;&#x2003;(2)

Continuous casting mold and method for continuous casting of steel (as amended)

In a method for oxygen-blowing refining of molten iron, an oxygen-containing gas as a main supply gas is supplied from an inlet side of a blowing nozzle for the oxygen-containing gas passing through an outer shell of the top-blowing lance and blown from the blowing nozzle while a control gas is jetted toward inside of the blowing nozzle for at least part of a period of the oxygen-blowing refining from a spout arranged in a side face of the nozzle at a site where the cross-sectional area of the nozzle minimum takes the minimum in the axial direction of the nozzle or a neighborhood thereof so that at least part of the spout exists in each space formed by dividing into two portions by an arbitrary plane passing through a central axis of the nozzle.

Method for oxygen-blowing refining of molten iron and top-blowing lance

When the decarburization refining of molten iron is performed by top-blowing oxygen gas from the top blowing lance, the oscillation of molten iron, a bubble burst, and spitting due to the bubble burst are suppressed. A refining method for a converter includes decarburizing molten iron in the converter with a top blowing lance having Laval nozzles disposed at the lower end thereof by blowing oxygen gas on the surface of the molten iron in the converter through the Laval nozzles, in which one or both of an oxygen feeding rate from the top blowing lance and lance height LH are adjusted in such a manner that an oxygen accumulation index S(F) is 40 or less.

Method for operating converter

A continuous casting mold including a water-cooled copper mold having a mold copper plate including an inner wall surface, recessed portions disposed partially or entirely in a region of the inner wall surface of the water-cooled copper mold from at least a position located at a meniscus to a position located 20 mm lower than the meniscus, and material-filled layers disposed in the recessed portions with a metal or nonmetal having a thermal conductivity different from that of the mold copper plate of the water-cooled copper mold. A shape of each of the recessed portions at a surface of the mold copper plate includes a curved surface.

Continuous casting mold and method for continuously casting steel

A continuous steel casting method includes producing a strand. The producing of the strand includes pouring molten steel into a mold of a continuous casting machine and withdrawing a solidified shell from the mold, the solidified shell being a solidified portion of the molten steel. The method includes applying a static magnetic field to at least a portion of a region of the strand, the strand being in the continuous casting machine, the region being a region where a solid fraction fs at a thickness-wise middle position of the strand is in a given range, the static magnetic field having a magnetic field strength of greater than or equal to 0.15 T and being in a direction orthogonal to a direction in which the strand is withdrawn, the static magnetic field being applied at an application time ratio of greater than or equal to 10%.

Continuous steel casting method

A high strength steel sheet having excellent surface quality and formability with a tensile strength of 980 MPa or more and a TS-El balance of 30000 MPa % or more is provided. A high strength steel sheet comprises: a chemical composition containing C: 0.08% to 0.30%, Si: 2.0% or less, Mn: more than 3.0% and 10.0% or less, P: 0.05% or less, S: 0.01% or less, Al: 1.5% or less, Ti: 0.010% to 0.300%, and N: 0.0020% to 0.0100% in a range satisfying 1.1&#x2264;(Ti+Mn/400)/(0.01+5N)&#x2264;6.0; and a microstructure including a retained austenite phase and a ferrite phase, wherein a ratio &#x3b3;Mn/&#x3b1;Mn of an average Mn concentration (&#x3b3;Mn) of the retained austenite phase to an average Mn concentration (&#x3b1;Mn) of the ferrite phase is 1.5 or more.

Material for high strength steel sheets, hot rolled material for high strength steel sheets, hot-rolled and annealed material for high strength steel sheets, high strength steel sheet, high strength hot-dip-coated steel sheet, high strength electroplated steel sheet, and method of manufacturing same

A continuous casting mold according to the present invention has plural separate portions filled with a metal of low thermal conductivity formed by filling a metal having a thermal conductivity of 30% or less of that of copper into circular concave grooves having a diameter of 2 to 20 mm which are formed in the region of the inner wall surface of the copper mold from an arbitrary position higher than a meniscus to a position 20 mm or more lower than the meniscus, in which the filling thickness of the metal in the portions filled with the metal of low thermal conductivity is equal to or less than the depth of the circular concave grooves and satisfies the relationship with the diameter of the portions filled with the metal of low thermal conductivity expressed by expression (1) below:0.5&#x2264;&#x2003;&#x2003;(1).

Continuous casting mold and method for continuous casting of steel

A molten steel refining method includes throwing a powder to molten steel while heating the powder with a flame formed by combustion of a hydrocarbon gas at the leading end of a top blowing lance. The lance height of the top blowing lance (the distance between the static bath surface of the molten steel and the leading end of the lance) is controlled to 1.0 to 7.0 m, and the dynamic pressure P of a jet flow ejected from the top blowing lance calculated from equation (1) below is controlled to 20.0 kPa or more and 100.0 kPa or less. P=&#x3c1;&#xd7; U/2 . . . (1) wherein P is the dynamic pressure (kPa) of the jet flow at an exit of the top blowing lance, &#x3c1;the density (kg/Nm) of the jet flow, and U the velocity (m/sec) of the jet flow at the exit of the top blowing lance.

Method for refining molten steel in vacuum degassing equipment

Conditions for soft reduction are determined in a method of continuous casting in accordance with a method utilizing the thickness of a slab strand to prevent center segregation from occurring in the strand due to an insufficient pressing rate or internal cracks from occurring in the strand due to an excessively high pressing rate.

Provided is a continuous casting method of steel that prevents a solidification completion position from being changed even when a drawing speed V of a cast slab is changed. The method includes drawing a cast slab by setting a drawing speed Vwhile spraying cooling water to the cast slab at a cooling water spray amount W[kg/ton-cast slab]. Then, changing the drawing speed to the speed Vwhile spraying cooling water to the cast slab at a cooling water spray amount W[kg/ton-cast slab]. The method further includes spraying cooling water to the cast slab at a cooling water spray amount Wt [kg/ton-cast slab] during a period of time t that is obtained by dividing a target length Lt by the drawing speed V. The water spray amount Wt satisfying either formula (1): Wt&#x3c;Wunder a condition of V&#x3c;V, or formula (2): Wt&#x3e;Wunder a condition of V&#x3e;V

Continuous casting method of steel

A method of producing a steel material includes a step of adding Ca to molten steel with an amount of Ca adjusted within a range satisfying the formula (1) below: where Ca is the amount [kg] of Ca added, y is an yield [%] of Ca, [S] is a concentration [% by mass] of S in the steel before addition of Ca, [AlO] is an amount [% by mass] of AlOin the steel before addition of Ca, and W is a weight [kg] of the molten steel.

Method of producing steel material

A method for refining hot metal in a converter using a top-blowing lance having a refining powder supply channel, a combustion oxidizing gas supply channel, and a refining oxidizing gas supply channel that are separate from each other includes supplying at least one of a lime-based flux, iron oxide, and a combustible material as a refining powder from the refining powder supply channel to a surface of the hot metal using a fuel gas or a mixture of the fuel gas and an inert gas as a carrier gas while supplying a combustion oxidizing gas from the combustion oxidizing gas supply channel to form a flame below a leading end of the top-blowing lance, and supplying a refining oxidizing gas from the refining oxidizing gas supply channel to the surface of the hot metal.

Method for refining hot metal in converter

A top-blowing lance includes a refining oxygen gas blowing nozzle having a plurality of ejection openings through which oxygen gas is blown into an iron bath in a reaction vessel, the ejection openings being disposed along a circular orbit at intervals, and a burner nozzle having an axis coaxial with the central axis of the circular orbit, forming a flame inside the refining oxygen gas blowing nozzle, and having ejection openings for blowing a powder heated by the flame into the iron bath, wherein an indicator A that indicates the positional relationship between the ejection openings of the refining oxygen gas blowing nozzle and the ejection openings of the burner nozzle satisfies the specified conditions.

Top-blowing lance and method for refining molten iron using the same

In a method for continuously casting an extremely low carbon steel using a continuous casting machine, by adjusting the chemical components of extremely low carbon steel within a specified range by taking into account an interface tension gradient in a concentration boundary layer on a front surface of a solidified shell, and also by optimizing intensities of the DC magnetic fields applied to the upper magnetic poles and the lower magnetic poles respectively corresponding to a slab width of a slab to be casted and a casting speed, it is possible to acquire the slab having high quality not only with the small number of defects caused by the entrainment of bubbles, non-metallic inclusion and a mold flux into the molten steel.

Continuous casting method for steel and method for manufacturing steel sheet

A steel continuous casting method using a continuous caster that includes a pair of upper magnetic poles and a pair of lower magnetic poles is disclosed. The method comprises braking a molten steel flow with DC magnetic fields respectively applied to a pair of upper magnetic poles and a pair of lower magnetic poles while stirring the molten steel with an AC magnetic field simultaneously applied to the pair of upper magnetic poles, the strength of an AC magnetic field applied to the upper magnetic poles and strengths of DC magnetic fields applied to the upper magnetic poles and the lower magnetic poles are controlled within a particular ranges in accordance with the width of a slab to be cast.

Steel continuous casting method

Growing community of inventors

Tokyo, Japan

Yuji Miki