Method for producing H-shaped steel and H-shaped steel product

Patent metadata

Field	Value
Publication number	US-10730087-B2
Application number	US-201615559373-A
Country	US
Kind code	B2
Filing date	Mar 10, 2016
Priority date	Mar 19, 2015
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

[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.

First claim

The invention claimed is:

1. A method for producing H-shaped steel using a slab as a material, the method comprising:
a rough rolling step;
an intermediate rolling step; and
a finish rolling step,
wherein in a rolling mill that performs the 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, and
the projections formed in the first caliber and the second caliber have a tip angle of 40° or less.

2. The method for producing H-shaped steel according to claim 1 , wherein a slab width of the slab is larger than a lower-limit slab width determined by an expression (5) below and is smaller than an upper-limit slab width determined by an expression (6) below:
lower-limit slab width=(product web inside dimension U +wedge height Ah× 2+slab thickness t )−inside-dimension widening amount Δ in subsequent mills,  Expression (5):

upper-limit slab width=slab edging amount+product web inside dimension U +inside-dimension widening amount Δ in subsequent mills,  Expression (6):

where subsequent mills refer to a group of a series of rolling mills that are subsequent to the web thinning caliber and perform widening of a web inside dimension.

3. The method for producing H-shaped steel according to claim 1 , wherein shaping in the plurality of calibers is performed under a condition that satisfies an expression (2) below,
where h denotes a flange half-width at the end of caliber shaping, and H denotes a flange half-width of an H-shaped steel product:
h≥H.   Expression (2):

4. The method for producing H-shaped steel according to claim 1 , wherein in the first caliber among the plurality of calibers, a caliber width of the caliber is substantially equal to a thickness of the material to be rolled in shaping using the caliber.

5. The method for producing H-shaped steel according to claim 1 , wherein in the second caliber among the plurality of calibers, shaping is performed in a state where an end surface of the material to be rolled is out of contact with a bottom surface of the caliber.

6. The method for producing H-shaped steel according to claim 1 , wherein in the plurality of calibers, shaping is performed in a state where an end surface of the material to be rolled is out of contact with a bottom surface of the caliber.

7. The method for producing H-shaped steel according to claim 1 , wherein the projections have a tip angle of equal to or more than 25° and equal to or less than 35°.

8. The method for producing H-shaped steel according to claim 1 , wherein the slab is a slab material whose slab width/slab thickness is equal to or more than 6.0 and equal to or less than 7.7, and the projections formed in the first caliber are designed to have a height of 100 mm or more.

9. The method for producing H-shaped steel according to claim 1 , wherein the plurality of calibers are engraved in a sizing mill.

10. The method for producing H-shaped steel according to claim 1 , wherein projections that are pressed against the divided parts to bend the divided parts are formed in the third caliber and subsequent calibers among the plurality of calibers, and the projections formed in the second caliber and subsequent calibers have tip angles sequentially increasing toward subsequent calibers.

11. The method for producing H-shaped steel according to claim 1 ,
wherein a slab width of the slab is larger than a lower-limit slab width determined by an expression (5) below and is smaller than an upper-limit slab width determined by an expression (6) below:
lower-limit slab width=(product web inside dimension U +wedge height Ah× 2+slab thickness t )−inside-dimension widening amount Δ in subsequent mills,  Expression (5):

upper-limit slab width=slab edging amount+product web inside dimension U +inside-dimension widening amount Δ in subsequent mills,  Expression (6):

where subsequent mills refer to a group of a series of rolling mills that are subsequent to the web thinning caliber and perform widening of a web inside dimension, and
in the first caliber among the plurality of calibers, a caliber width of the caliber is substantially equal to a thickness of the material to be rolled in shaping using the caliber.

12. The method for producing H-shaped steel according to claim 1 ,
wherein a slab width of the slab is larger than a lower-limit slab width determined by an expression (5) below and is smaller than an upper-limit slab width determined by an expression (6) below:
lower-limit slab width=(product web inside dimension U +wedge height Ah× 2+slab thickness t )−inside-dimension widening amount Δ in subsequent mills,  Expression (5):

upper-limit slab width=slab edging amount+product web inside dimension U +inside-dimension widening amount Δ in subsequent mills,  Expression (6):

where subsequent mills refer to a group of a series of rolling mills that are subsequent to the web thinning caliber and perform widening of a web inside dimension, and
the projections have a tip angle of equal to or more than 25° and equal to or less than 35°.

13. The method for producing H-shaped steel according to claim 1 ,
wherein a slab width of the slab is larger than a lower-limit slab width determined by an expression (5) below and is smaller than an upper-limit slab width determined by an expression (6) below:
lower-limit slab width=(product web inside dimension U +wedge height Ah× 2+slab thickness t )−inside-dimension widening amount Δ in subsequent mills,  Expression (5):

upper-limit slab width=slab edging amount+product web inside dimension U +inside-dimension widening amount Δ in subsequent mills,  Expression (6):

where subsequent mills refer to a group of a series of rolling mills that are subsequent to the web thinning caliber and perform widening of a web inside dimension,
in the first caliber among the plurality of calibers, a caliber width of the caliber is substantially equal to a thickness of the material to be rolled in shaping using the caliber, and
the projections have a tip angle of equal to or more than 25° and equal to or less than 35°.

Assignees

• Nippon Steel Corp

Inventors

• Yamashita Hiroshi

Classifications

• B21B27/02

  Shape or construction of rolls (for rolling metal of indefinite length in repetitive shapes specially designed for the manufacture of particular objects B21H8/02 {; B21B27/005 takes precedence}) · CPC title

• B21B1/088 Primary

  H- or I-sections · CPC title

• B21B2261/02

  Transverse dimensions · CPC title

• B21B1/026

  Rolling · CPC title

• B21B2001/028

  Slabs · CPC title