A milling apparatus includes a plurality of milling roller units each including one milling roller that is made contact with, by pressing, one surface of one of a plurality of differently angled plate parts of an elongated metal milling material and another milling roller that is made contact with another surface of the plate part by pressing. At least one of the milling roller units mills a plate part different from a plate part milled by any other milling roller unit. A plurality of the milling roller units configured to mill an identical plate part are installed in a longitudinal direction of the plate part. The one milling roller and the other milling roller of at least one of the milling roller units are movable in axial directions thereof.

[Object] To suppress occurrence of shape defects in a material to be rolled and enable efficient and stable production of an H-shaped steel product with a flange width larger than a conventional flange width by creating deep splits on end surfaces of a material (e.g., slab) using projections with acute-angle tip shapes, and sequentially bending formed flange portions.

[Solution] Provided is a method for producing H-shaped steel, the method including: a rough rolling step; an intermediate rolling step; and a finish rolling step. In a rolling mill that performs the rough rolling step, a plurality of calibers to shape a material to be rolled are engraved, the number of the plurality of calibers being four or more. Shaping of one or a plurality of passes is performed on the material to be rolled in the plurality of calibers. In a first caliber and a second caliber among the plurality of calibers, projections to create splits vertically with respect to a width direction of the material to be rolled are formed. In a second caliber and subsequent calibers among the plurality of calibers, reduction is performed in a state where end surfaces of the material to be rolled are in contact with caliber peripheral surfaces in shaping of at least one pass. In a third caliber and subsequent calibers among the plurality of calibers, a step of sequentially bending divided parts formed by the splits is performed.

[Object] To suppress occurrence of shape defects in a material to be rolled and enable efficient and stable production of an H-shaped steel product with a flange width larger than a conventional flange width by creating deep splits on end surfaces of a material (e.g., slab) using projections with acute-angle tip shapes, and sequentially bending formed flange portions.

[Solution] Provided is a method for producing H-shaped steel, the method including: a rough rolling step; an intermediate rolling step; and a finish rolling step. In a rolling mill that performs the rough rolling step, a plurality of calibers to shape a material to be rolled are engraved, the number of the plurality of calibers being four or more. Shaping of one or a plurality of passes is performed on the material to be rolled in the plurality of calibers. In a first caliber and a second caliber among the plurality of calibers, projections to create splits vertically with respect to a width direction of the material to be rolled are formed. In a second caliber and subsequent calibers among the plurality of calibers, reduction is performed in a state where end surfaces of the material to be rolled are in contact with caliber peripheral surfaces in shaping of at least one pass. In a third caliber and subsequent calibers among the plurality of calibers, a step of sequentially bending divided parts formed by the splits is performed.

A bending method feeds a long workpiece material made of metal and having a plurality of thickness portions disposed at different angles between rollers and bends the workpiece material. An initial shape of the workpiece material is a straight line or a bend with a bend radius larger than a target bend radius, a thickness of a cross section of the workpiece material along a bend radius direction is set to increase from an inner side toward an outer side of the bend radius direction, the workpiece material is fed between the rollers and rolled in a way that an amount of rolling in a region corresponding to the outer side of the bend radius direction is larger than an amount of rolling in a region corresponding to the inner side, and the workpiece material is bent to have the target bend radius from the initial shape.

A bending method feeds a long workpiece material made of metal and having a plurality of thickness portions disposed at different angles between rollers and bends the workpiece material. An initial shape of the workpiece material is a straight line or a bend with a bend radius larger than a target bend radius, a thickness of a cross section of the workpiece material along a bend radius direction is set to increase from an inner side toward an outer side of the bend radius direction, the workpiece material is fed between the rollers and rolled in a way that an amount of rolling in a region corresponding to the outer side of the bend radius direction is larger than an amount of rolling in a region corresponding to the inner side, and the workpiece material is bent to have the target bend radius from the initial shape.

[Object] To produce an H-shaped steel product with a flange width larger than a conventional flange width by, in a rough rolling step using calibers in producing H-shaped steel, creating deep splits on end surfaces of a material (e.g., slab) using projections with acute-angle tip shapes, and sequentially bending flange portions formed by the splits.

[Solution] Provided is a method for producing H-shaped steel using a slab as a material. In a rolling mill that performs a rough rolling step, a plurality of calibers to shape a material to be rolled, and a web thinning caliber to thin a web of the material to be rolled that has been shaped in the plurality of calibers are engraved, the number of the plurality of calibers being three or more. Shaping of a plurality of passes is performed on the material to be rolled in part or all of the plurality of calibers. In a first caliber and a second caliber among the plurality of calibers, projections to create splits vertically with respect to a width direction of the material to be rolled are formed. In a third caliber and subsequent calibers among the plurality of calibers, a step of sequentially bending divided parts formed by the splits is performed. The projections formed in the first caliber and the second caliber have a tip angle of 40 or less.

[Object] To produce an H-shaped steel product with a flange width larger than a conventional flange width by, in a rough rolling step using calibers in producing H-shaped steel, creating deep splits on end surfaces of a material (e.g., slab) using projections with acute-angle tip shapes, and sequentially bending flange portions formed by the splits.

[Solution] Provided is a method for producing H-shaped steel using a slab as a material. In a rolling mill that performs a rough rolling step, a plurality of calibers to shape a material to be rolled, and a web thinning caliber to thin a web of the material to be rolled that has been shaped in the plurality of calibers are engraved, the number of the plurality of calibers being three or more. Shaping of a plurality of passes is performed on the material to be rolled in part or all of the plurality of calibers. In a first caliber and a second caliber among the plurality of calibers, projections to create splits vertically with respect to a width direction of the material to be rolled are formed. In a third caliber and subsequent calibers among the plurality of calibers, a step of sequentially bending divided parts formed by the splits is performed. The projections formed in the first caliber and the second caliber have a tip angle of 40 or less.

This H-beam steel contains, in mass %, C, Si, Mn, Al, Ti, N, O, Nb, and B. The H-beam steel has composition in which the amount of Nb and the amount of B satisfy, in mass %, 0.070Nb+125B0.155, and has a metal structure in which, in a microstructure, an area fraction of bainite is not less than 70%, a total of an area fraction of pearlite and an area fraction of cementite is not more than 15%, and the remainder is at least one of ferrite and island martensite. The effective crystalline-grain size of the bainite is not more than 40 m, and the thickness of a flange falls in a range of 12 to 40 mm.

This H-beam steel contains, in mass %, C, Si, Mn, Al, Ti, N, O, Nb, and B. The H-beam steel has composition in which the amount of Nb and the amount of B satisfy, in mass %, 0.070Nb+125B0.155, and has a metal structure in which, in a microstructure, an area fraction of bainite is not less than 70%, a total of an area fraction of pearlite and an area fraction of cementite is not more than 15%, and the remainder is at least one of ferrite and island martensite. The effective crystalline-grain size of the bainite is not more than 40 m, and the thickness of a flange falls in a range of 12 to 40 mm.

A method for manufacturing a monolithic component with integral branching points, including providing a sheet metal comprising a first section and a second section, thinning, via rollforming, the first section of the sheet metal, splitting, via split-rollforming, the second section of the sheet metal in a plane parallel to a surface area of the second section, such that a first flange portion and a second flange portion is formed.