JPH04220102A - Method for hot rolling channel steel - Google Patents

Abstract

PURPOSE:To adjust the thickness of web and flange on-line and continuously- variably by finish rolling with a finishing universal rolling mill which consists of horizontal rolls with variable barrel width and vertical rolls. CONSTITUTION:In reverse rolling with a 2-high rough forming mill E1 and rough universal rolling mill R1, an intermediate stock 102 with a prescribed thickness and width is made and it is made into a channel intermediate stock 106 by alternatively rolling with a double rolling mill R2 which two lines of chevron grooves and flat bottom grooves are provided on the same rolls and a double edger E2. Successively, the height W of the web is fixed by regulating the inside width WE of the channel intermediate stock 106 with a finishing horizontal roll 8b and vertical rolls 9a, 9b. Because the width B of flange is already regulated into a prescribed size BE with the upper and lower horizontal rolls 5a, 5b of the double edger E2, the width B of flange of a product after finish rolling is fixed, even if the thickness of web is different.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling method for producing channel steel having various web and flange thicknesses and widths from continuously cast slabs with high efficiency.

0002

[Prior Art] Cold-formed square columns, which are widely used as construction steel columns, are based on "JSSC Report No. 5 Standardization of Box Columns" published by the Japan Steel Construction Association in August 1985. It is manufactured by cold working by either the roll forming method shown in FIG. 5 or the press forming method shown in FIG. 6.

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 earthquake resistance. 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 material used here, hot-rolled channel steel, is required to have a constant outer width (web height, flange width), adjustable thickness, and low production costs comparable to general shape steel.

[0006]

As a typical example of manufacturing conventional hot rolled channel steel, a case using a reverse mill is shown in FIG. 3, and a case using a continuous mill is shown in FIG. 41, respectively.

[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. Therefore, the outer width within the same series is constant.
In order to meet product requirements for channel steel of various plate thicknesses, it is necessary to prepare dedicated rolling rolls and rolling accessories for 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 in order 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 its web and flange without replacing any roll tools. The purpose of the present invention is to provide a method for hot rolling channel steel, which allows stepless online thickness adjustment.

[0009]

[Means for Solving the Problems] The present invention advantageously solves the above-mentioned drawbacks, and its gist is that two or three chevron-shaped holes are formed, and the openings are numbered in opposite directions. A continuous cast slab is roughly formed into a composite chevron-shaped rough material having two or three consecutive chevron portions by a double rough rolling mill with slotted rolls, and then the composite chevron-shaped rough material is passed through a double rough-shaping rolling mill and a rough universal. After reverse rolling with a rolling mill to form a composite mountain-shaped intermediate material with a predetermined thickness and width, two consecutive mountain-shaped holes and a flat-bottomed hole are installed on the same roll, and the two rolling mills are placed in close proximity to each other to enable continuous rolling. The composite chevron-shaped intermediate material is reverse rolled by a double rolling mill and a double edger arranged in the same direction to elongate the web bending part and shape the flange end to form a groove-shaped intermediate material, and then to form a groove-shaped intermediate material. This is a hot rolling method for channel steel that produces channel steel in the same series with a constant outer width and different thickness by finishing rolling with a finishing universal rolling mill consisting of horizontal rolls and hard rolls.

0010

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 rolling process and equipment array for carrying out the method of the present invention.

The rolling process in the present invention can be roughly divided into a rough rolling process consisting of a double rough rolling mill BD, a double rough shaping mill E1 and a rough universal rolling mill R1, and a rough rolling process consisting of a double rough rolling mill R2 and a double edger. It consists of three steps: an intermediate rolling step consisting of E2 and a finish rolling step using finishing universal rolling mill F.

First, the double rough rolling mill BD in the rough rolling process
consists of upper and lower horizontal rolls 1a and 1b, and a box hole type G1 and two pair hole types G2 and G3 are drilled in these rolls. Continuously cast slab 100, which is to be rolled rough material, is width-edged by box-hole die G1, and after peeling off and sizing of heated scale, it is shaped into a chevron shape by cyclic rolling (alternating rolling) with two hole-hole die G2 and G3. The composite material 101 is roughly formed into a composite chevron-shaped material 101.

[0014] The hole shape here means, for example, the shape of the hole G5 and hole G6 drilled in the upper and lower horizontal rolls 50a and 50b for rolling angle iron shown in FIG. 7, and both hole shapes are the same. Although the holes are excavated by rolls 50a and 50b, the openings O1 and O2 at the left and right ends of each hole type are formed in positions opposite to each other.

[0015] By alternately rolling with these two grooves, the edges of the rolled material are reliably forged and shaped.
It has the advantage that the number of holes is small and large sizes can be rolled with a relatively short roll body length.

[0016] Angular steel is the simplest shaped steel in which the outside width is constant within the same series, and products of arbitrary thickness can be obtained by adjusting the interval between the upper and lower rolls. We focused on the effect of using a hole die in the rolling of angle-shaped steel, and applied this to the rolling of channel steel.

[0017] The degree of bending of the center portion of the hole-type web used in the present invention and the shape and dimensions of the lateral development of both sides of the flange portion are determined by the strength of the roll, the shapeability of the flange tip, and the rolling posture. It should be decided based on stability.

Next, the composite chevron-shaped material 101 rough-shaped by the double rough rolling mill BD is rolled into a predetermined shape by a double rough-shaping mill E1 and a rough universal rolling mill R1, which are arranged in close proximity to enable continuous rolling. The composite chevron-shaped intermediate material 102 has a thickness and a width of . Specifically, the width edging of the tip of the flange is performed using the vertical rolls 4a and 4b of the rough universal rolling mill R1 while being restrained by the upper and lower horizontal rolls 3a and 3b, thereby forming the flange into a desired width dimension.

The upper and lower horizontal rolls 2a and 2b of the double rough shaping mill E1 are used to shape bulging (local swelling) that occurs in the thickness direction of the material due to the edging in the width direction of the vertical rolls 4a and 4b. Then, build the required board 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.

[0020] The features of the roll hole type in the double rough shaping mill E1 and the rough universal rolling mill R1 are that in order to accommodate thickness-free sizes, the difference in the rolling reduction rate in the cross section due to rolling up and down of the rolls, and the width difference between sizes. In order to suppress the (line length difference), the shape is a combination of chevron shapes, and the apex angles of the left and right chevrons are set at right angles in consideration of ease of forming in the subsequent stage. Taking edging into consideration, both ends that accommodate flanges are formed horizontally.

The intermediate rolling process consists of a double rolling mill R2 and a double edger E2.
A series of chevron hole type KAL5 and flat bottom hole type KAL3 are provided side by side on the same upper and lower horizontal rolls 4a and 4b. In addition, a double edger E2 is provided adjacent to this double rolling mill R2 so as to enable continuous rolling, and this edger E2 has two series of chevron hole type KAL4 and a flat bottom hole type similar to the double rolling mill R2. KAL2 is installed on the same upper and lower horizontal rolls 5a and 5b.

[0022] The composite chevron-shaped intermediate material 102 is first partially stretched at the flange curved portion and the web bent portion by two series of chevron-shaped hole types KAL5 of the double rolling mill R2, and then the intermediate rough material 1 is formed.
03, then edging to make the outer width of the flange constant and shaping of the flange end portion is performed using two series of chevron-shaped holes KAL4 of the double edger E2, and an intermediate rough material 104 is obtained.

Here, the shape of the double chevron hole type KAL4 of the double edger E2 is as shown in the figure.
The left and right recesses restrain the apex portion 104a of the intermediate rough material 104, and the left and right recesses of the lower horizontal roll 5b restrain the flange ends of the intermediate rough material 104.

Furthermore, by forming a constant gap C1 on the inner surface of the web of the intermediate raw material 104 and the lower horizontal roll 5b, and making the web unrestricted, the flange width can be kept constant even if the thickness of the web changes. We are making it possible to regulate.

[0025] Two series of chevron hole type KA having such a configuration
After obtaining the predetermined thickness and width through reverse multi-pass stretching and rolling using L5 and KAL4, the web bent portions are smoothed using the flat-bottom hole type KAL3 of the double rolling mill R2, and the web bent portions are straightened. Accordingly, the flange portion automatically becomes approximately perpendicular to the web portion, and the groove-shaped intermediate member 105
get.

The feature of the hole shape of the flat bottom hole type KAL3 is that the width l of the flat top convex portion 41b of the lower horizontal roll 4b is set to a width sufficient for smoothing the web bent portion of the groove type intermediate material 105. , a gap C is provided between the flat top convex portion 41b, the side surface, and the inner surface of the horizontal roll 4a so that it can accommodate various flange thicknesses.
2, and then the flange end and lower horizontal roll 4b.
There is also a slight gap between the bottom and the bottom.

Next, the flat bottom hole type K of the double edger E2
At AL2, finish edging to make the outer width (BE) of the flange constant and finish shaping of the flange end are performed to create the groove-shaped intermediate material 1.
Get 06.

Here, the outer circumferential surface and both side surfaces of the flat-top convex portion 51b of the lower horizontal roll 5b forming the flat-bottom hole type KAL2 leave the inner surface of the groove-shaped intermediate material 106 unrestricted. That is, it corresponds to various web flange thicknesses of the groove-shaped intermediate member 106, and allows edging adjustment to maintain a constant outer width (BE) of the flange.

Finally, the groove-shaped intermediate material 106 is rolled by the variable body width upper and lower horizontal rolls 8a of the universal rolling mill F in the finish rolling process.
, 8b and vertical rolls 9a, 9b, a channel steel 107 of the same series with a constant outer width and a free size thickness is finished rolled.

Specifically, the inner width WE of the groove-shaped intermediate material 106
By regulating the web to a predetermined size using the finishing horizontal roll 8b and the vertical rolls 9a and 9b, the web height W becomes constant. Since the flange width B is already regulated to a predetermined size BE by the upper and lower horizontal rolls 5a and 5b of the double edger E2, the flange width B of the product after finish rolling is constant even if the web thickness is different. .

[0031]

[Effects of the Invention] As explained above, according to the hot rolling method of the present invention, the roll hole dimensions of the part where the thickness and width of the web and flange of the channel steel are formed can be arbitrarily changed online. , it is possible to easily roll channel steel of the same series with a constant outer width and a free thickness, making it possible to handle small volume production of multiple sizes and eliminating the need for roll replacement work, improving production efficiency and reducing roll tool costs. can. Moreover, stretch rolling can be performed even in the intermediate rolling process, so
Efficient rolling can be performed by making maximum use of the existing H-beam rolling equipment specifications. In addition, corner R when using conventional so-called roll forming or press forming products.
However, according to the present invention, the corner R portion becomes sharp and the utility value of the product is improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a rolling process in which the method of the present invention is carried out.

FIG. 2 is a drawing showing an example of the arrangement of a rolling apparatus for carrying out the method of the present invention.

FIG. 3 is an explanatory diagram showing a hot rolling process using a conventional reverse mill.

FIG. 4 is an explanatory diagram showing a hot rolling process using a conventional continuous mill.

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

FIG. 6 is an explanatory diagram showing a method of forming a column material using a conventional press and a work hardening position.

FIG. 7 is an explanatory diagram showing the hole pattern in the chevron-shaped rolling roll and its pass situation.

[Explanation of symbols]

BD Double rough rolling mill E1 Double rough shaping mill R1 Rough universal rolling mill R2 Double rolling mill E2 Double edger F Finishing universal rolling mill G2, G3 No. hole type KAL4, KAL5 Double chevron hole type KAL2, KA
L3 Flat bottom hole mold 100 Continuous casting slab 101 Composite chevron-shaped rough material 102 Composite chevron-shaped intermediate material 103, 104 Intermediate rough material 105, 106 Channel-shaped intermediate material 107 Channel steel (product)

Claims (1)

[Claims] [Claim 1] A continuous casting slab is formed into two or three series of chevrons by a double rough rolling mill having two or three series of chevron-shaped groove rolls with openings facing oppositely to each other. The compound chevron rough material is formed into a composite chevron intermediate material having a predetermined thickness and width by reverse rolling with a double rough shaping rolling mill and a rough universal rolling mill, and then a double chevron shape is formed. A double rolling mill and a double edger, in which a groove type and a flat-bottomed groove type are installed on the same roll, and the two rolling mills are arranged in close proximity to each other to enable continuous rolling, reverse roll the composite angle-shaped intermediate material to form a web. The bent part is stretched and the flange end is shaped to form a groove-shaped intermediate material, which is then finished rolled by a finishing universal rolling mill consisting of horizontal rolls with variable body width and hard rolls, to improve the outer width of the same series. A method for hot rolling channel steel, characterized by producing channel steel having constant but different thicknesses.