JPH04238603A - Hot tandem mill line for channel steel - Google Patents

Abstract

PURPOSE:To produce small quantity of many sizes, to save the labor for changing the roll and to effectively roll with the line of tandem mill by steplesswise executing the adjustment of the web thickness and the flange thickness while keeping the dimension of outer width constant in the same series on the hot rolling of channel with the continuous case slab as the stock. CONSTITUTION:The channel steel of different thickness with the constant dimension of outer width in the same series is manufactured by cooperating a two hight roughing mill BD, if necessary, two high shaping mill RH and universal roughing mill RU, and composing a U-bending machine VE having a vertical roll which forms the flange part P for shaping the end part of flange on the circumferential surface and the horizontal roll, universal finishing mill FU having a horizontal roll which presses the inner side surface of flange and the web, horizontal roll which presses the web outer side surface and right and left vertical rolls which press the outer side surface of the flange.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a hot rolling equipment train for channel steel, and more specifically, channel steel with uniform web and flange thickness and various thicknesses and widths are produced from continuous casting slabs. This invention relates to a row of hot rolling equipment for producing channel steel with high efficiency.

0002

[Prior Art] Cold-formed square columns, which are widely used as construction steel columns, are known, for example, from the "JSSC Report No. 5 Standardization of Box Columns" published by the Japan Steel Construction Association in August 1988. It is manufactured by cold working by either the roll forming method shown in FIG. 4 and the press forming method shown in FIG.

However, in these methods, the yield ratio (YR: yield point or yield strength/
tensile strength) is slightly high.

[0004] On the other hand, it is said in some circles that a lower YR for members used in super high-rise buildings and the like is desirable from the standpoint of seismic performance. One way to deal with this problem is to weld and assemble a box (square column) using hot-rolled channel steel as a material.

[0005] This assembly method is compatible with the recent labor-saving trend at construction sites because it is possible to incorporate the diaphragm before welding and assembly. The hot-rolled channel steel used as the material here is a parallel uniform plate with a constant outer width (web height and flange width) and an adjustable thickness (the web and flange thickness are the same and the flange inner surface has no taper). thickness), and low production costs are required to be on par with general shaped steel.

[0006]

[Problems to be Solved by the Invention] As a typical example of manufacturing conventional hot-rolled channel steel, a reverse mill described as a prior art in Japanese Patent Application Laid-Open No. 2-133102, which was previously proposed by the applicant of the present invention, has been proposed. The method using a continuous mill is shown in FIG. 6, and the method using a continuous mill is shown in FIG.

[0007] In these conventional methods, even within a product group with the same web height series, for example, the horizontal roll 40 of the finishing mill F uses a roll whose body width W0 is constant. Therefore, if the flange thickness t differs, the web height W will be different. In addition, since rough and intermediate forming is performed using the hole pattern of double rolls, it is extremely difficult to produce various thicknesses over a wide range by simply adjusting the gap between the same rolls.

[0008] Therefore, in order to meet the product requirements for channel steel of constant outer width and various plate thickness sizes within the same series, it is necessary to prepare dedicated rolling rolls and their rolling accessories according to each size. For this reason, there is a problem that not only does the cost of rolling tools increase, but also production efficiency is significantly reduced, such as a reduction in operating rate due to roll replacement.

The present invention has been made to solve the above-mentioned drawbacks, and it is possible to maintain the outer width of the same series of rolled channel steel while maintaining the web and flange without replacing any roll tools. The purpose of the present invention is to provide a row of hot rolling equipment for channel steel that can perform stepless online thickness adjustment.

0010

[Means for Solving the Problems] The gist of the present invention is as follows. That is, a double rough rolling mill having upper and lower horizontal rolls with box-shaped holes and flat holes drilled therein, which rolls a hot slab material with a rectangular cross section into a flat plate material of a predetermined thickness and width, and a central outer surface of the flat plate material. A horizontal roll that presses the outer surface of the flat plate material, and a pair of left and right truncated conical vertical rolls that have flanges for shaping the flange ends on the outer circumferential surface that presses the outer surfaces on both sides of the flat plate material. A U-bending forming machine that bends a material, and upper and lower horizontal rolls and flanges that are variable in body width and are comprised of a horizontal roll that presses the flange of the intermediate material and the inner surface of the web, and a horizontal roll that presses the outer surface of the web. This is a hot rolling equipment line for channel steel consisting of a universal finishing mill having a pair of left and right vertical rolls that press the outer surface.

[0011] Furthermore, in the above hot rolling equipment row for channel steel, a double roughing mill and a universal roughing mill are provided in close proximity to each other to enable continuous rolling between the double roughing mill and the U-bending forming machine. This is a row of rolling mills.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention and their functions will be explained in detail with reference to the drawings.

FIGS. 1 and 2 show an example of a hot rolling equipment row for channel steel according to the present invention.

In FIG. 1(a), 1a and 1b are upper and lower horizontal rolls of a double rough rolling mill BD in the rough rolling process, and these rolls have a plurality of box hole types G1, G2, G3 and flat hole type G4. is being excavated. Using a hot slab with a rectangular cross section made by the continuous casting method as a raw material, we edged it from the width direction with a box hole type G1 to form the end face and peel off the scale, then turned it 90 degrees and processed it with a flat hole type G4. Perform thickness reduction.

[0015] Here, the steel material is appropriately turned 90 degrees in the middle of the thickness reduction over multiple passes, and is edged multiple times with one of the box hole dies G1, G2, and G3 to shape the end face and adjust the width dimension. , and roll it into a flat plate material 10 of the required width and thickness. The required number of box-hole molds and their dimensions are determined by the required board thickness and material thickness, and are not necessarily G1, G2, G3.
It is not limited to the three hole types.

Next, the flat plate material 10 rolled by the double roughing mill BD consists of a universal roughing mill RU shown in FIG. 1(b) and a double shaping mill RH shown in FIG. 1(c). A flat plate material 1 with a specified width and thickness is reverse rolled in the rolling process.
2.

In the universal rough rolling mill RU, the width edging of the tip of the flange is performed using the vertical rolls 3a and 3b while the material to be rolled is restrained by the upper and lower horizontal rolls 2a and 2b.
Form to the required width dimension. The upper and lower horizontal rolls 2a and 2b may be split horizontal rolls whose body widths can be arbitrarily changed as required.

The double shaping rolling mill RH shapes the bulging (local swelling) that occurs in the thickness direction of the material due to the edging of the vertical rolls 3a and 3b of the universal roughing mill RU in the strip width direction, and also forms the required shape. Stretch and roll to thickness. Here, the amount of width reduction and thickness reduction per pass is regulated by the specifications of the rolling mill and the conditions of the rolled material, so it is necessary to Perform reverse rolling twice.

It should be noted that the universal rough rolling mill RU and the double shaping rolling mill RH cannot roll the flat plate material 12 having various widths and thicknesses with the double rough rolling mill BD alone due to the number of roll holes and efficiency. It is used when there is a shortage and restrictions on the rolling length of the steel material are a problem, and if there are no problems with such operating conditions, a universal roughing mill RU and a double shaping mill RH are used. There is no problem even if the subsequent rough rolling step is omitted.

Subsequently, the flat plate material 12 is U-shaped into a groove-shaped intermediate material 13 having a substantially U-shaped cross section by the left and right vertical rolls 6a, 6b and the horizontal roll 5 of the U-bending forming machine VE shown in FIG. 1(d).
It is bent and formed.

Left and right vertical rolls 6a, 6 of U bending machine VE
The shape of b is a truncated cone, and its outer circumferential surface presses the outer surface of the flange of the groove-shaped intermediate member 13, and the flange P provided at one end of the outer circumferential surface positions the flange end surface and shapes the flange end. .

The horizontal roll 5 is a cylindrical roll with a flat outer peripheral surface, and presses the outer surface of the web of the groove-shaped intermediate material 13.

The left and right vertical rolls 6a, 6b are basically driven, but the horizontal roll 5 may not be driven, and may be driven to follow the running speed of the material. Further, the left and right vertical rolls 6a, 6b and the horizontal roll 5 have a structure in which the rolling down can be adjusted for each pass.

The bending positions 13a and 13b of the groove-shaped intermediate material 13 (vertical corners of the channel steel) can be controlled by adjusting the roll gap between the left and right vertical rolls 6a and 6b and the horizontal roll 5, so that the flat plate material of appropriate dimensions can be controlled. In combination with 12, the groove-shaped intermediate material 13 having the required width and thickness can be formed using the same roll.

[0025] The number of passes of the U-bending forming machine VE is determined by the amount of U-bending, and the larger the size, the more passes need to be made, and usually 3 to 7 passes of reverse rolling.

In the first pass, the flat plate material 12 is deformed downward by restraining it with a roller table so that the direction of bending in the cross section is upward as shown in KAL2 in FIG. Pre-bending rolls 41a and 41b having large arc-shaped holes as shown in FIG.
It is even more reliable if the material is pre-deformed in the process.

Here, the preliminary bending rolls 41a and 41b are
The upper and lower horizontal rolls 4a and 4b of the double shaping rolling mill RH can be used within the range where there is no problem in forming plate materials of various widths and thicknesses in the same hole type.
There is no problem in using it also.

[0028] Once the material has been bent upward, it can be easily subjected to U-bending with a small load and power after the second pass. Further, the roll gap of the final pass of KAL2 is set so that the web width WB (corresponding to the web height of the product) of the groove-shaped intermediate material 13 is approximately the same as the web height W of KAL1, which will be described later.

[0029] If WB is too large with respect to W, KAL1
If it is too small, the outer corners of the channel steel may be chewed out, folding flaws and wrinkles may occur on the inner corners, and the web surface may become curved.On the other hand, if it is too small, the outer corners will lack thickness, and the lower horizontal roll Scratches and the like occur on the inner corner portion at 7b.

The flange tip width WD of the groove-shaped intermediate material 13 is:
The inclination of the inclined portions T of the left and right vertical rolls 6a, 6b of KAL2 is designed to be about 6 to 18% so that the flange width B is about 6 to 18% larger than WB.

If WD is too large than W, biting and threading defects will occur in KAL1, and conversely, if WD is too small, KA
This causes poor engagement at L1 and causes scratches on the flange surface.

Next, as shown in FIG. 1(e), the groove-shaped intermediate material 13 is rolled in the universal finishing mill F in the finishing forming process.
U horizontal rolls 7a, 7b with variable body width, vertical rolls 8a,
8b, it is finish rolled into a channel steel 14 in the same series with a constant outer width and a free size thickness.

This universal finishing mill FU has the same structure as a conventional universal mill for general shaped steel in that it has upper and lower horizontal rolls and left and right vertical rolls. However, the horizontal rolls of the universal finishing mill in the apparatus train of the present invention have the following characteristics.

That is, in FIG. 1(e), the horizontal roll 7b that presses the flange and the inner surface of the web is divided into two parts so that the body width can be changed in the left-right direction, and the outer surface 71b of this roll is aligned with the roll axis. The roll outer peripheral surface 72b is formed as a flat surface parallel to the roll axis. Then, according to the thickness of each product, the body width interval of the left and right split rolls is adjusted, the outer surface 71b of the roll presses the flange inner surface of the channel steel 14, and the outer peripheral surface 72b of the roll presses the flange of the channel steel 14. Press the inside surface.

[0035] A horizontal roll 7 presses the outer surface of the web.
Since the body width of a is constant within the same series, if the roll is not intended to be shared between series, a conventional integral roll may be used instead of a variable body width roll.

A pair of vertical rolls 8a and 8b are provided on the left and right so as to press the entire width of the outer surface of the flange of the channel steel 14. By using such a universal finishing mill, in KAL1 shown in FIG. 1, the portions corresponding to the flanges and webs of the groove-shaped intermediate material 13, which is the entry side material, are rolled into predetermined positions by the horizontal roll 7a and the vertical rolls 8a, 8b. By regulating the size to , channel steel 14 having a constant web height W and flange width B can be obtained with various thicknesses. Here, a thickness reduction rate of about 0.5 to 5% is added to stabilize the shape and reduce the corner R portion.

[0037] The number of passes is basically a single pass, but if the number of passes is increased and further rolling is performed, it will be more effective to reduce the corner R portion.

By applying the above method to a section steel rolling mill, for example, from a continuously cast slab of width 1400 mm x thickness 250 mm, web height 700 mm x flange width 350 mm x thickness 19, 22, 25, 28, 32, 36
, 40, 45, 50, 55, 60, and 65 mm of constant outer width channel steel can be made using the same roll set.

[0039]

[Effects of the Invention] According to the present invention, the roll hole dimensions of the part where the thickness and width of the web and flange are built can be changed arbitrarily online, so that the groove shape steel of the same series with a constant outer width and a free size thickness can be used. It can be hot-rolled, making it possible to handle small-lot production of multiple sizes, and eliminating the need for roll replacement work, improving production efficiency and reducing roll tool costs.

Furthermore, the corner radius of conventional so-called roll forming or press forming products is 2 to 3 times the thickness of the plate.
However, according to the present invention, the corner radius can be made relatively small, which improves the utility value of the product.

[Brief explanation of the drawing]

FIG. 1 is a drawing showing an example of rolling by a rolling apparatus array according to an embodiment of the present invention.

FIG. 2 is a drawing showing an example of a rolling mill row according to an embodiment of the present invention.

FIG. 3 is an explanatory view showing an example of preliminary bending forming of channel steel in the present invention.

FIG. 4 is an explanatory diagram showing a conventional method of forming a column material using rolls and a work hardening position.

FIG. 5 is an explanatory diagram showing a method of forming a column material using a conventional press and a work hardening position.

FIG. 6 is a drawing showing a hot rolling process using a conventional reverse mill.

FIG. 7 is a drawing showing a hot rolling process using a conventional continuous mill.

[Explanation of symbols]

BD Double roughing mill RU Universal roughing mill RH Double shaping mill VE U bending machine FU Universal finishing mill 1a, 1b Upper and lower horizontal rolls 2a, 2 of double roughing mill
b Upper and lower horizontal rolls 3a, 3 of the universal rough rolling mill
b Left and right vertical rolls 4a, 4b of the universal rough rolling mill
Upper and lower horizontal rolls 5 of double shaping rolling mill
Horizontal rolls 6a, 6b of U bending machine Left and right vertical rolls 7a, 7b of U bending machine Upper and lower horizontal rolls 8a, 8b of universal finishing rolling machine Left and right vertical rolls 10, 11, 12 of universal finishing rolling machine Flat material 13 Grooved Intermediate material 14 Channel steel

Claims (2)

[Claims] 1. A double rough rolling mill having upper and lower horizontal rolls drilled with box-shaped holes and flat holes for rolling a hot slab material with a rectangular cross section into a flat plate material of a predetermined thickness and width, and said flat plate material. A horizontal roll that presses the central outer surface of the plate material, and a pair of left and right truncated conical vertical rolls that press the outer surface of both sides of the flat plate material and have flanges for shaping the flange ends on the outer circumferential surface of the plate material. A U-bending forming machine that bends a shaped intermediate material, a horizontal roll whose body width can be changed and which presses the flange of the intermediate material and the inner surface of the web, and a horizontal roll that presses the outer surface of the web. A hot rolling equipment line for channel steel consisting of a horizontal roll and a universal finishing mill having a pair of left and right vertical rolls that press the outer surface of the flange. 2. The heat treatment of the channel steel according to claim 1, wherein a double rough rolling mill and a universal rough rolling mill are provided in close proximity to each other to enable continuous rolling between the double rough rolling mill and the U-bending forming machine. Inter-rolling equipment row.