Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Nippon Steel Engineering Co., Ltd.

Tooru Akashi

Koji Noguchi

Kenji Yamada

Masaki Tanaka

Shigeru Ogawa

Takeo Itoh

Shingo Kuriyama

Yoshihiro Serizawa

Daisuke Kasai

Masao Sakashita

Tetsuo Kishimoto

Noriyuki Hishinuma

Kazuki Shiokawa

Hitoshi Nikaido

Yoji Nakamura

Takayuki Otsuka

Seiji Arizumi

Hisamoto Wakabayashi

Fuminori Tasaki

Yuki Takeuchi

Yasumitu Kondo

Shuuichi Hamausu

Yasumitsu Kondou

Hiroki Matsubara

Shuuichi Hamauzu

A coil skid on which a hot-rolled coilobtained by coiling a hot-rolled steel sheet is placed includes: at least two or more layers of a metal plateand at least two or more layers of a heat insulating materialeach stacked alternately, in which the metal plateis in contact with the hot-rolled coil. The uneven cooling of an outer peripheral portion of the hot-rolled coil caused by the coil skid is prevented while ensuring the strength of the coil skid, to thereby inhibit the uneven hardness in the longitudinal direction of the hot-rolled coil resulting from this uneven cooling.

Coil skid and steel sheet manufacturing method

Flatness of a hot-rolled steel sheet in a coil is improved when the hot-rolled steel sheet is wound with a mandrel in a hot-rolling process to manufacture a coil. The mandrel has a protruding shape with a center portion in an axial direction protruding from both end portions when seen from a lateral side in the axial direction. Regarding a peripheral length difference, which is a difference between a peripheral length of the center portion of the mandrel and a peripheral length at a predetermined distance from the center portion, the ratio of the peripheral length difference to the peripheral length of the center portion is preferably 0.0002 to 0.012. The protruding shape may be a trapezoidal shape or a polynomial function shape.

Manufacturing apparatus and manufacturing method of hot-rolled coil

A provisional elongation strain difference distribution &#x394;&#x3b5;(x) of a metal strip during rolling is found under conditions in which out-of-plane deformation of the metal strip is restrained. A critical buckling strain difference distribution &#x394;&#x3b5;(x) is found based on the provisional elongation strain difference distribution &#x394;&#x3b5;(x), a strip thickness and strip width of the metal strip, and tension acting on the metal strip at exit from a rolling mill. When the provisional elongation strain difference distribution &#x394;&#x3b5;(x) exceeds the critical buckling strain difference distribution &#x394;&#x3b5;(x), the difference between the provisional elongation strain difference distribution &#x394;&#x3b5;(x) and the critical buckling strain difference distribution &#x394;&#x3b5;(x) is found, and added to the provisional elongation strain difference distribution &#x394;&#x3b5;(x) to find a true elongation strain difference distribution &#x394;&#x3b5;'(x). Rolling conditions are set based on the true elongation strain difference distribution &#x394;&#x3b5;&#x2032;(x), and the metal strip is rolled, thereby controlling the metal strip's profile.

Rolling control method for metal strip, rolling control apparatus, and manufacturing method for rolled metal strip

The apparatus for cooling a hot-rolled steel sheet of the invention includes a thermometer that measures the temperature of the hot-rolled steel sheet; a shape meter that measures a shape of the hot-rolled steel sheet; a top side cooling device that cools a top surface of the hot-rolled steel sheet in a cooling section; a bottom side cooling device that cools a bottom surface of the hot-rolled steel sheet in the cooling section; and a control device that controls at least one of an amount of heat dissipated from the top surface by cooling and an amount of heat dissipated from the bottom surface by cooling of the hot-rolled steel sheet in the cooling section by controlling the top side cooling device and the bottom side cooling device based on temperature measurement results and shape measurement results.

Apparatus for cooling hot-rolled steel sheet

A method for manufacturing a steel sheet of the invention includes a hot-rolling process in which a steel material is hot-rolled using a finishing mill so as to obtain a hot-rolled steel sheet; and a cooling process in which the hot-rolled steel sheet is cooled. The hot-rolling process includes a target steepness-setting process in which a target steepness of the edge wave shape is set based on first correlation data indicating a correlation between a steepness of the edge wave shape of the hot-rolled steel sheet and a temperature standard deviation Y; and a shape-controlling process in which operation parameters of the finishing mill are controlled so as to match the steepness of the edge wave shape with the target steepness.

Method for manufacturing steel sheet

The method for cooling a hot-rolled steel sheet of the invention includes a target ratio-setting process in which a top and bottom heat transfer coefficient ratio X1, at which a temperature standard deviation Y becomes a minimum value Ymin, is set as a target ratio Xt based on correlation data between a top and bottom heat transfer coefficient ratio X of the hot-rolled steel sheet and the temperature standard deviation Y of the hot-rolled steel sheet; and a cooling control process in which at least one of an amount of heat dissipated from a top surface by cooling and an amount of heat dissipated from a bottom surface by cooling of the hot-rolled steel sheet in the cooling section is controlled so that the top and bottom heat transfer coefficient ratio X of the hot-rolled steel sheet in the cooling section matches the target ratio Xt.

Method for cooling hot-rolled steel sheet

A cooling apparatus for hot rolling is installed on a downstream side of a finishing mill of a continuous hot rolling mill, and cools a steel sheet rolled by the finishing mill while being conveyed. The cooling apparatus includes first pinch rolls which, during an interval when the steel sheet fed out from a final stand of the finishing mill moves from a position of the final stand to a position where a surface temperature of the steel sheet reaches 850&#xb0; C. or less, pinch the steel sheet while applying tension of 3.9 MPa or greater.

Cooling apparatus and cooling method for hot rolling

The oxide film thickness of the steel material surface (d+d) is made to become 15 nm or less where post-treatment after water-cooling is not needed by suitably setting the conditions of the water-cooling start temperature (T), water-cooling end temperature (T), steel material thickness (d), concentration of solute oxygen in the cooling water (D), and cooling rate (C) in the equation of d+d=7.98&#xd7;10(T&#x2212;T)dD+{5.50&#xd7;10(T&#x2212;T)&#x2212;6.51(T&#x2212;T)}/C.

Water-cooling method of steel material

Suppression and removal of scales are efficiently carried out in a steel material hot rolling process and the time of pickling treatment as a successive step is greatly shortened. In a water cooling step of metallic material at a temperature of 100&deg; to 1,200&deg; C., scales are removed by applying a direct current or an alternating current to metallic material at 0.1 to 10 A/m of unit surface area from pinch rolls to rolls or apron guides on the outlet side of a hot rolling mill and/or by injecting cooling water at a pH value of &minus;2 to 4 onto the metallic material from cooling headers and apron guides

Method of removing scales and preventing scale formation on metal materials and apparatus therefor

Growing community of inventors

Tokyo, Japan

Tooru Akashi