JP2001340902A - Channel steel with parallel flange having constant outward dimension and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide high quality channel steel with paralleled flanges having a constant outside dimension, in which the channel steel does not cause any troubles in a manufacturing process of a square steel pipe pillar containing a built-in diaphragm. SOLUTION: The square steel pipe pillar containing a built-in diaphragm, which satisfies the following equations, |inward width of web-(nominal web height-nominal flange width×2)|<=+2 mm, or |flange perpendicularity deviation|<=+2 mm, is manufactured by using only the channel steel with paralleled flanges having the constant outside dimension.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for a square steel tubular column used as a pillar of a high-rise or super-high-rise building, for example, in which the thickness and width of a web and a flange have various dimensions, and The present invention relates to a parallel flange channel (PFC) having a constant external method, that is, a constant external dimension, and a method for producing the steel by hot rolling.

[0002]

2. Description of the Related Art It is said in some cases that a lower yield ratio (YR) of a rectangular column member widely used as a column material in a high-rise building or the like is desirable from the viewpoint of earthquake resistance. One of the countermeasures is to weld and assemble channel steel (hereinafter referred to as hot rolled channel steel) manufactured by hot rolling into a box (square column). This assembling method allows the diaphragm to be built-in before welding and assembling, thus contributing to labor saving at the box manufacturing site.

[0003] The hot rolled channel steel used as the material here has the same outer dimensions (web height x flange width) in the same series.
It is demanded that the thickness be free size and that it can be produced at a low cost comparable to general shape steel.

[0004] By the way, as a typical example of a conventional method of manufacturing a hot-rolled channel steel, a coarse material for a channel steel is continuously reverse-rolled by a coarse universal mill and an edger mill, and then finished by a finishing universal mill. There are a method of performing rolling, and a method of performing continuous rough rolling and intermediate rolling by continuously combining rolling mills provided with double rolls engraved with a large number of dies, followed by finishing with a finishing universal mill.

However, in these production methods, even within the same web height series product group, since the roll width of the horizontal roll of the finishing universal mill is constant, if the flange thickness is different, the web height is reduced. Will be different.

Further, in the latter method, since the rough / intermediate rolling step is performed using a double-hole type roll, it is very difficult to form various thicknesses over a wide range only by adjusting the gap with the same roll.

[0007] Therefore, a product group that can be separately produced only by adjusting the gap with the same roll, that is, the external dimensions within the same series.
(Web height, flange width) In order to meet the product demand for grooved steel with constant and various thicknesses, it is necessary to prepare rolling rolls and rolling auxiliary equipment (guides) for each size. . For this reason, there has been a problem that not only the burden on the rolling rolls and guides is increased, but also that the productivity of the factory is significantly reduced, such as a reduction in the operation rate due to the change of the rolls.

In view of the above problems, recently, without changing the roll guide at all, the outer dimensions of the channel steel in the same series (web height × flange width) are kept constant while the web and the flange are kept constant. There have been proposed various methods for hot rolling a parallel flange channel steel capable of performing the thickness adjustment of a steel plate online in a stepless manner.

[0009] For example, in the method disclosed by the present applicant in Japanese Patent Application Laid-Open No. 9-141302, in the intermediate rolling following the rough rolling, the inner method is performed using a tandem mill group including a first universal mill and a double type edger mill. Without a fixed channel-shaped intermediate slab, the web height and flange width of the slab were simultaneously reduced in one pass by a second universal mill to stabilize the web height and flange width, and then the universal finishing mill Finish rolling is performed.

Further, the method for manufacturing a constant outer flange channel steel disclosed in Japanese Patent No. 2,577,660 has a double-hole type roll in which a continuous cast slab is formed with two or three chevron-shaped holes. After roughly shaping into a chevron rough material by a rough rolling machine, a reverse rough rolling of a double rough forming rolling machine and a rough universal rolling mill is performed to obtain a chevron intermediate material, and another double hole type roll rolling machine, an edger rolling mill, and the like. To form a second channel intermediate material, and finally finish rolling is performed by a finishing universal rolling mill comprising a horizontal roll and a vertical roll having the same width. In this method, Japanese Patent Application Laid-Open No. 9-141302
In comparison with the method disclosed in Japanese Patent Laid-Open Publication No. H10-163, two more rolling mills are required.

FIG. 1 shows a schematic shape of a parallel flange channel steel having a constant outer dimension (outer dimension). Although not shown in FIG. 1, generally, the inner side of the joint (fillet) between the web and the flange is provided with a radius of 10R to 30R.

[0012]

However, the above-mentioned prior art for producing a hot-rolled channel steel having a fixed outer dimension has the following problems.

FIGS. 2 (a) to 2 (d) are schematic cross-sectional views showing steps of manufacturing a rectangular steel column by welding and assembling a parallel flanged steel using a diaphragm. In (a), the diaphragm 10 is inserted by half into the parallel flanged steel 12. At this time, the shape of the diaphragm 10 is, as shown in the cross section AA ', four sides of the flat plate 14 surrounded by the upper and lower frames 16, 16. The other half of the diaphragm 10 is inserted into another parallel flange 12 as shown in FIG. 2 (b). After assembling in this manner, as shown in FIG. 2 (c), the periphery of the diaphragm 10 is welded to the inner wall of the section steel by, for example, electroslag welding.
The flange section steel itself is butt-welded at the notch (
Example: Submerged welding).
The state of joining of the diaphragm 10 and the parallel flanged steel 12 at this time is as shown in the BB 'section. In this way, a square steel tubular column 20 shown in FIG. 2 (d) is obtained.
In addition, specific construction operations such as welding are already known,
Further description is omitted.

As shown in FIG. 2, as a use of a channel steel having a constant outer dimension, a reinforcing member 10 called a diaphragm is sandwiched at a plurality of longitudinal positions, and two parallel flange channel steels 12 and 12 are used. Are generally welded together by, for example, butt welding, and used as square steel pipe columns 20 for high-rise buildings.

Therefore, strict dimensional accuracy is required for the product shape. However, since it is manufactured by hot rolling, there is a problem that an error from a target dimension occurs in the longitudinal direction every time the steel is manufactured, or even with a single channel steel.

It has been clarified that the following problems arise in the process of actually manufacturing a square steel tubular column when an error occurs in the dimension of the parallel flange channel steel having a constant outer method. (1) Problems related to poor flange perpendicularity Fig. 3 shows an example of flange perpendicularity failure of parallel flanged channel steel.
These are shown in (a) and (b).

Generally, the perpendicularity of the flange is evaluated by the degree of inclination of the left and right flanges with respect to the web surface, and the angle between the front end of the flange and the plane perpendicular to the web with respect to the joint (fillet) between the flange and the web. Display as a gap.
Further, the plus and minus are distinguished and displayed depending on whether the flange is bent inside or outside (in the case of a bent outside the flange as shown in FIG. 3A, the squareness is displayed plus).

In addition, as shown in FIG. 3 (b), the inner width of the web is set at ₂ between the flange tip (h ₂ ) and the vicinity of the fillet (h ₁ ).
It is also possible to measure the location and simply display it as 1/2 of the difference between them (= h ₂ −h ₁ ).

In the case of the in-flange breakage (h ₁ > h ₂ ) among the flange perpendicularity failures, if the degree is large, FIG.
Troubles as shown in (a) and (b) occurred in steps 1 and 2 of the manufacturing process of the square steel column shown in FIG.

That is, since the front end portion of the flange is inclined inward, the front end portion of the diaphragm interferes with the diaphragm in the process of inserting the diaphragm into the channel steel, so that the diaphragm cannot be inserted into the channel steel. Occurred.

The diaphragm size (full width) is the nominal value of the inner width of the web of the parallel flange channel steel (= the nominal web height-2 ×
(Nominal flange thickness) is generally reduced by 1 to 3 mm, and roundness of about 10R to 30R is added to the four corners of the diaphragm (not shown) in accordance with the radius of the fillet portion of the channel steel. However, it has been found that the above trouble occurs when the flange is bent inward beyond a specific range.

Next, among the flange perpendicularity defects, if the flange is broken outside (h ₁ <h ₂ ), if the degree is large, FIG.
The trouble shown in FIG. 2 occurred in step 3 of FIG.

That is, the step of inserting the diaphragm into the channel steel because the tip of the flange is inclined outward.
(Step 1 or Step 2) is no problem, but as shown in Step 3, when the diaphragm is welded (electroslag welding) to the flange portion of the two parallel flanged channel steels,
As shown in the B 'cross-sectional view, it was found that the welding material leaked from the gap between the diaphragm and the inner surface of the flange, which hindered the work process. In addition, it has been found that the above-described trouble occurs when the flange is bent outside the specified range. (2) Problems related to flange inner width variation The flange inner width variation of the manufactured parallel flanged channel steel with constant outer method is large, and the flange inner width is less than the nominal value (= nominal web height-2 × nominal flange thickness). On the other hand, for the smaller ones, if the degree is large, the trouble as shown in FIGS. 5 (a) and 5 (b) may occur, as shown in FIG.
It occurred in step 1 and step 2 of (b).

That is, since the distance between the left and right flange tips is too small, the flange tip and the diaphragm interfere with each other in the process of inserting the diaphragm into the channel steel, and the diaphragm cannot be inserted into the channel steel. Occurred.

In general, the diaphragm dimensions (total width) are made to be smaller by 1 to 3 mm than the nominal value of the inner width of the web of the parallel flanged channel steel, and at the four corners of the diaphragm,
Although not shown, 10R is added to the R of the fillet of the channel steel.
It has been found that the above-mentioned trouble occurs when the inner width of the flange becomes smaller than a specific range, since the roundness of about 30 R is provided.

Next, in the case where the variation in the inner width of the flange is large and the inner width of the flange is larger than the nominal value (= nominal web height−2 × nominal flange thickness), if the degree is large, FIG. The trouble shown in FIG. 2 occurred in step 3 of FIG.

That is, since the distance between the left and right flange tips is large, the process of inserting the diaphragm into the channel steel is performed.
(Step 1 or Step 2) is no problem, but as shown in Step 3, when the diaphragm is welded (electroslag welding) to the flange portion of the two parallel flanged channel steels,
As shown in the B 'cross-sectional view, it was found that the welding material leaked from the gap between the diaphragm and the inner surface of the flange, which hindered the work process. In addition, it has been found that the above-mentioned trouble occurs when the inner width of the flange exceeds a specific range.

In addition, the above-described welding work troubles delay the subsequent manufacturing process, and require a great deal of time and expense for rework and re-welding, thereby increasing the manufacturing cost.

Here, the object of the present invention is to provide a rectangular parallelepiped channel steel as a raw material in view of the above-mentioned problems in the production and quality control of the conventional parallel flange channel steel having a constant outer method. An object of the present invention is to provide a channel steel having a parallel flange with a constant outer method and excellent quality, which does not hinder the production process of a steel pipe column, and a method for producing the same.

[0030]

Means for Solving the Problems The present inventor has conducted extensive studies through extensive rolling experiments and trial production tests of square steel tubular columns, and as a result, has optimized the shape and dimensional accuracy of a parallel flange channel steel with a constant outer method. The present inventors have found that the above-mentioned problems can be solved by performing the manufacturing process management for the purpose, and have completed the present invention. (1) The rolled material is rough-rolled, then subjected to intermediate rolling, and finally, the outer method is manufactured through finishing rolling using a finishing universal rolling mill incorporating a split horizontal roll capable of changing the width online. A parallel flanged channel steel, wherein the inner width of the product web after the completion of the production of the channel steel satisfies the relationship of the following formula. Flange channel steel.

| Internal width of product web-(Nominal web height-Nominal flange thickness x 2) | ≤ +2 mm (2) After roughly rolling the rolled material and then subjecting it to intermediate rolling, finally the width can be changed online. A fixed external flange channel steel manufactured through finish rolling using a finishing universal rolling mill incorporating a split horizontal roll, and the product flange perpendicularity after the completion of the production of the channel steel is as follows: An externally defined parallel flange channel steel for a square steel tube column with a built-in diaphragm that satisfies the relationship.

| Flange perpendicularity | ≤ + 2 mm (3) The rolled material is roughly rolled, then the web height is made constant in the intermediate rolling, and finally a split horizontal roll capable of changing the width online is incorporated. A method for producing a parallel flange channel steel having an external method in which finish rolling is performed using a finishing universal rolling mill, wherein the inner width of the web after completion of finish rolling of the channel steel and cooling to room temperature has the following relationship. A method for producing a parallel flange channel steel having a constant outer diameter for a square steel tubular column having a built-in diaphragm, wherein the width of a horizontal roll of the finishing universal rolling mill is adjusted so as to be satisfactory.

| Inner width of web− (Nominal web height−Nominal flange thickness × 2) | ≦ + 2 mm (4) The rolled material is roughly rolled, then the web height is made constant in the intermediate rolling, and finally, A method of manufacturing a constant external flange channel that performs finish rolling using a finishing universal rolling mill incorporating a split horizontal roll capable of changing the width online, and finish rolling the channel and cooling to room temperature. Outer constant for square steel tube columns with built-in diaphragms, characterized by setting the side angles of the horizontal and vertical rolls of the above finishing universal rolling so that the flange perpendicularity after completion satisfies the following formula Of manufacturing parallel flange channel steel.

| Flange perpendicularity | ≦ + 2 mm (5) After rough rolling of the rolled material, and then, in the intermediate rolling, the web height is made constant, and finally, a finish incorporating a split horizontal roll capable of changing the width online. A method for producing a constant parallel flanged channel steel in which finish rolling is performed using a universal rolling mill, wherein the finish squareness of the grooved steel and the flange perpendicularity after completion of cooling to room temperature satisfy the following formula: A method for producing a fixed external flange channel steel for a rectangular steel tube column having a built-in diaphragm, wherein a rolling load in the finish universal rolling is adjusted so as to perform the above process.

| Flange perpendicularity | ≤ + 2 mm (6) Inspect the dimensions and shape of the parallel flange channel steel with a constant outer diameter, and | Web inner width-(nominal web height-nominal flange thickness x
2) A method for manufacturing a square steel tubular column with a built-in diaphragm, characterized by using only a constant external flange groove steel that satisfies | ≦ + 2 mm or | flange perpendicularity | ≦ + 2 mm.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the drawings. FIG. 6 illustrates, as an example of a manufacturing process of a channel steel for carrying out the present invention, a rolling process (rolling line) of an externally fixed parallel flange channel steel, together with a roll die of each rolling mill.

The rolling process according to the present invention can be roughly classified into a double rolling mill (hereinafter referred to as a breakdown rolling mill).
, A rough rolling process consisting of a first coarse universal rolling mill and a double-roll type rolling mill (hereinafter referred to as an "edger rolling mill") and an intermediate rolling process consisting of a second coarse universal rolling mill, and a finishing process comprising a finishing universal rolling mill It consists of three rolling steps.

Breakdown rolling mill in rough rolling process
Reference numeral 30 denotes a pair of upper and lower horizontal rolls. In addition to a box hole type for edging a continuous casting slab 32 heated to about 1300 degrees, which is a raw material, to a predetermined width, this roll has a shape shown in FIG. As shown, two types of butterfly-shaped holes 34,
35 is engraved. CC of rolling material in rough rolling process
(Continuous casting) The slab is formed into a rough flanged steel slab 36 of a parallel flange channel steel through reverse rolling using two types of butterfly-shaped cavities after width edging with a box-shaped cavity.

The rough shaped billet 36 formed by the breakdown rolling mill 30 is sent to an intermediate rolling step, and a plurality of coarse steel billets 36 are formed by using a first rough universal rolling mill 40 and an edger rolling mill 42 which are installed close to each other so as to be capable of continuous rolling. By tandem reversal rolling of the pass, it is stretched and rolled to a shape close to a predetermined product thickness and flange width.

The coarse universal rolling mill 40 is composed of a pair of upper and lower horizontal rolls and a pair of left and right vertical (vertical) rolls. The thickness of the web between the upper and lower horizontal rolls, and the thickness of the flange is reduced and stretched by the gap between the vertical rolls and the side of the horizontal rolls. I do. At this time, bulging portions 44 are formed at both ends of the web (joining portions between the flange and the web) as shown in the figure.

The bulging portion 44 is reduced by rolling in a plurality of passes by the edger rolling mill 42, and is thereafter flattened by the rolls of the second coarse universal rolling mill 46 by rolling in one pass.

That is, between the stepped portion provided on the outer peripheral surface of the vertical roll of the second rough universal rolling mill 46 and the small diameter portion provided on the side surface of the variable width lower horizontal roll, the flange width is positively reduced and the first width is reduced. The bulging portions 44 at both ends of the web generated by the rough universal rolling mill 40 are flattened.

In the final rolling step, which is the final step, the material to be rolled has a predetermined web / flange thickness by one-pass or multiple-pass shaping using a finishing universal rolling mill 50 incorporating a variable width lower horizontal roll. And a product with web height and flange width.

In FIG. 6, a second rough universal rolling mill is shown.
The width W ₂ of the outer peripheral surface of the lower horizontal roll 44 is determined by the horizontal roll width W ₁ of the first coarse universal rolling mill 40 and the hole shape of the edger roll in rolling passes other than the web height reduction rolling pass of the material to be rolled. The width (≒ W ₁ ) is set to substantially the same value, and is set to be narrower than the horizontal roll width W _{1 of} the first coarse universal rolling mill 40 for the first time in the web height reduction rolling pass of the material to be rolled. .

The width W ₃ of the outer peripheral surface of the lower horizontal roll of the finishing universal rolling mill 50 is the same as that of the second coarse universal rolling mill.
It is set approximately equal to the horizontal roll width W ₂ of 46. Further, although the web horizontal rolls of the second coarse universal rolling mill 46 and the finishing universal rolling mill 50 are shown as rolls having a fixed width in FIG. 6, variable width rolls whose roll width can be freely changed online are shown. is there.

The inventor of the present invention prepared a product in which the inner width of the web and the perpendicularity of the flange of the parallel flanged channel steel were varied in various ways through a large number of in-situ rolling experiments, and the product was used as a material. Steps 2 (a) to 2 (d)
A test was conducted to prototype a square steel tubular column by assembling and welding it together. Thus, the present invention was devised based on the various findings described below obtained. (1) Relationship between flange perpendicularity and trouble in assembling and welding rectangular steel tube columns Table 1 shows the nominal dimensions of the externally fixed flanged channel steel as the raw material, the measured values of the flange perpendicularity at both ends of the product, and the product used. The following summarizes the situation when square steel tubular columns were manufactured. The number of products in each row of the table was four, and therefore, two square steel tubular columns were manufactured for each row.

Here, the nominal size is a so-called design size, and is a size defined as a standard. Also called nominal dimensions. In this specification, the flange perpendicularity is calculated from the web inner widths h ₁ and h ₂ shown in FIG. 3 (b), and the flange perpendicularity = (h ₂ −h ₁ ) × 1/2. did.

Although the web inner width (h ₁ ) at this time is not shown, when both ends of all products were actually measured, it was found that the nominal dimensions (= nominal web height−nominal flange thickness × 2) were obtained. On the other hand, it was in the range of +3.0 to -2.0 mm.

From the above, it was found that the following relationship had to be satisfied in order not to cause any trouble in the process of manufacturing the square steel tubular column. That is, -2mm ≤ product flange perpendicularity ≤ + 2mm

[0050]

[Table 1] (2) Relationship between variations in web inner width and troubles in assembling / welding of square steel tubular columns Table 2 shows the nominal dimensions of the outer fixed parallel flange groove steel used as the material, the nominal values of the web inner width calculated from the dimensions, and both ends of the product. The following summarizes the actual measured values of the web inner width of the section and the situation when a square steel tubular column was manufactured using the product. The number of products in each row of the table was 4, and therefore, two square steel tubular columns were manufactured for each row. Incidentally, the web in the width in the table indicates a value corresponding to h ₁ in FIG. 3 (b).

Although the flange perpendicularity is not shown, when both ends of all products were actually measured, it was +3.0.
It was in the range of 2.52.5 mm. From this, it was found that the following relationship must be satisfied in order to prevent trouble during machining of the diaphragm in the manufacturing process of the square steel tubular column. That is, −2 mm ≦ Web inner width− (Nominal web height−Nominal flange thickness × 2) ≦ + 2 mm

[0052]

[Table 2] (3) Relationship between inner web width and finishing universal mill width variable horizontal roll width State in which the parallel flange channel steel of the present invention is finish-rolled by a universal mill incorporating a split horizontal roll capable of changing the width online, and then cooled to room temperature. In addition to the width of the above-mentioned divided horizontal rolls, the width of the divided horizontal rolls due to the hot shrinkage is about 4 to 6 mm smaller than the width of the divided horizontal rolls. It becomes smaller by about 1 to 2 mm due to the direction deflection.

Therefore, in order not to cause a defect in the inner width of the web of the product, it is necessary to previously set the inner width of the web of the parallel flange groove steel immediately after the finish rolling to about 5 to 8 mm larger than the target dimension. . That is, it is necessary to set the width of the divided horizontal rolls to be larger by about 5 to 8 mm before rolling.
Conversely, if the inner width of the web after completion of cooling to room temperature greatly deviates from the target, the width of the divided rolls needs to be set narrower in advance. (4) Relationship between flange perpendicularity and finish universal mill roll side angle The parallel flange channel steel of the present invention is finished rolled by a universal mill incorporating a split horizontal roll capable of changing the width online, and then cooled to room temperature. The angle that the product flange makes with respect to the vertical plane is the angle that the split horizontal roll and vertical roll surface make with respect to the vertical plane.
(Side angle) is reduced by about 2 to 4 mm in the direction in which the left and right flange tips approach each other (flange bending direction) due to the relationship between the temperature difference between the inside and outside of the channel and the resulting difference in hot shrinkage allowance. (See FIG. 7 (a)).

Therefore, in order to prevent a flange perpendicularity defect of the product from occurring, it is necessary to set the front ends of the left and right flanges of the parallel flange channel steel immediately after the finish rolling in such a manner that the front ends thereof are opened by about 2 to 4 mm. That is, it is necessary to set the side angles of the divided horizontal roll and the vertical roll in advance so that the flange is bent outside the flange (see FIG. 7B).

In the optimal setting of the roll side angle, it is necessary to determine the roll side angle in consideration of the web height, flange width, web / flange thickness, finishing temperature, and the like of the product. (5) Relationship between flange perpendicularity and finishing universal mill rolling load A product in which the parallel flange channel steel of the present invention is finish-rolled by a universal mill incorporating a split horizontal roll capable of changing the width online, and then cooled to room temperature. The angle that the flange makes with respect to the vertical plane is generally the angle that the split horizontal roll and vertical roll surface make with respect to the vertical plane.
In relation to the (side angle), the temperature difference between the inside and outside of the channel and the resulting difference in the hot shrinkage allow the tip of the left and right flanges to approach each other (bending direction in the flange).
It becomes smaller (see FIG. 7 (a)).

However, when the thickness reduction of the flange is large or the temperature of the flange is lowered during the finish rolling, the rolling load in the thrust direction becomes excessive, and as a result, the deflection of the divided horizontal roll in the width direction becomes large. And the right and left flange ends of the product may be apart from each other (outward bending direction), causing a flange perpendicularity defect.
(See FIG. 8 (a)). Such a flange perpendicularity defect
In order to prevent (bending out of the flange), it is necessary to appropriately set a rolling pass schedule so that the finishing rolling load does not become excessive.

That is, when the flange thickness reduction becomes large, it is necessary to take measures such as increasing the number of finish rolling passes (see FIG. 8B). The method of hot rolling of the parallel flange channel steel having a constant outer method of the present invention is not limited to the method described in FIG. 6, and any method in which a variable width horizontal roll is incorporated into a finishing universal rolling mill and shaping rolling is performed. Any method of reducing or enlarging the inner web width in the intermediate rolling may be used. For example, it goes without saying that the method of manufacturing a parallel flanged steel channel having a constant outer diameter disclosed in Japanese Patent No. 2577660 may be used.

It goes without saying that the number of rolling passes in the finishing universal rolling mill may be one or plural. The on-line width changing mechanism of the split horizontal rolls in the finishing universal rolling mill is already known per se, and the present invention may utilize it.

[0059]

EXAMPLES Further, the method of rolling a channel steel according to the present invention will be described more specifically with reference to data of examples.

A rolling mill in which both upper and lower horizontal rolls have a variable width structure is arranged as a second coarse universal rolling mill.
(The web height W and the flange width B) are constant,
Various kinds of parallel flange channel steels having different web thickness and flange thickness were manufactured. That is, the manufactured parallel flange channel steel has a nominal size of any of web height B: 600 mm,
Flange width B: 300 mm, web thickness, flange thickness: 22-60 mm.

The width W ₁ of each of the upper and lower horizontal rolls of the first coarse universal rolling mill 40 was 561 mm, and the angle between the sides of the upper and lower horizontal rolls and the vertical line was 5 degrees. Moreover, the caliber width of the lower grooved roll edger rolling mill 42 is equal to the width W ₁ of the horizontal rolls of the first rough universal rolling mill 40 561Mm
The hole depth was 278 mm.

The depth from the outer peripheral surface of the variable width lower horizontal roll to the small diameter portion of the second coarse universal rolling mill 46 was 240 mm, and the width W ₂ of the outer peripheral surface of the variable width lower horizontal roll was initially set to 561 mm. The variable width of each of the variable width horizontal rolls of the second coarse universal rolling mill 46 and the variable width horizontal roll of the finishing universal rolling mill 50 was 100 mm.

By such a rolling step, first, the thickness:
A continuous casting slab with a rectangular cross section of 250 mm and width: 1000 mm is used as a rolling material, charged into a heating furnace and heated to about 1300 ° C., and then subjected to reverse rolling of 11 to 13 passes using a breakdown rolling machine 30. To form a rough shaped steel slab having a thickness of 80 to 100 mm.

Next, the coarse steel slab is reverse-rolled in 5 to 9 passes by using a first coarse universal rolling mill 40, an edger rolling mill 43 and a second coarse universal rolling mill 46, and the thickness of the web and the flange thickness are reduced. Was stretched and rolled to predetermined values.

At this time, the web thickness and the flange thickness are reduced by the first coarse universal rolling mill 40, and the flange width is reduced by the edger rolling mill and the second coarse universal rolling mill.
It was reduced by 46.

Thereafter, for the intermediate rolled material having a product thickness other than 22 mm, in the last pass of the second coarse universal rolling mill 46, the width of the upper and lower variable width horizontal rolls is reduced and the opening of the vertical roll is adjusted to be narrower. Thereafter, the web was reduced to reduce the height of the web by [(product thickness−22) × 2] mm, a maximum of 76 mm, and the flange width was adjusted and rolled.

In order to prevent a defective product shape, the thickness of the product
For intermediate rolled materials of 40 mm or less, the maximum reduction in web height by one pass of rolling is 36 mm at maximum, and for products with a product thickness of more than 40 mm and 60 mm or less, rolling is performed in two or three passes. , Reduced the web height by up to 76mm.

The degree of opening of the upper and lower horizontal rolls of the second coarse universal rolling mill 46 was set to be equal to the web thickness in each pass of the intermediate rolled material. In this way, for the intermediate rolled material after the intermediate rolling, by the finishing universal rolling mill 50, in consideration of the heat shrinkage allowance in the product cooling process after the finish rolling, the width of the width variable upper horizontal roll is 606 m
m and the width of the width-variable lower horizontal roll was changed online to 488 to 564 mm each time according to the product thickness.

The opening degree of the upper and lower variable width horizontal rolls was set to a value equivalent to the web thickness of the product, and finished. The angle (side angle) between the side of the lower horizontal roll of the finishing universal rolling mill 50 and the side of the vertical roll opposite to the vertical surface (side angle) is set to 0.25 degrees in the direction of bending the flange outside, and the number of finish rolling passes is 3 passes. And

Table 3 shows the representative size of the externally formed constant parallel flange channel steel manufactured by the method of the present invention and the result of measurement of the product dimensions after finish rolling and cooling to room temperature. For comparison, when the method of the present invention is not satisfied, that is, when the side angles of the lower horizontal roll and the vertical roll of the finishing universal rolling mill 50 are 0 degrees (Comparative Example 1), and the finishing universal rolling mill 50 performs one-pass finishing. (Comparative Example 2) is also shown.

[0071] Incidentally, the web in the width of the table is that of the h ₁ in FIG. 3 (b), the flange perpendicularity is a value measured by placing a right angle gauge, based on the web surface for the flange each of the left and right , Plus indicates bending outside the flange, and minus indicates bending inside the flange.

These dimensions were measured at both ends and the center (position 6 m from the end) for each product, and the minimum and maximum values were displayed.

[0073]

[Table 3] From this table, it can be seen that the present invention makes it possible to manufacture a parallel flange channel steel having a constant outer method without causing variations in the inner width of the web and defective flange perpendicularity.

Further, an angled steel tubular column having a size of 600 mm × 600 mm was prepared by the method shown in FIGS. 2 (a) to 2 (d) by using the externally formed constant parallel flange channel steel manufactured by the method of the present invention. Also, no trouble occurred during the diaphragm welding process.

On the other hand, with regard to the externally fixed parallel flange channel steel described as a comparative example, troubles in the square steel pipe column manufacturing process due to poor flange perpendicularity and unevenness in the inner width of the web (defects when inserting a diaphragm, diaphragm welding, etc.) Frequent reworking and reworking occurred frequently, and the production cost of square steel tubular columns rose.

Although the above embodiment has been described in detail with reference to the rolling process of FIG. 6 as an example, it goes without saying that the present invention exerts the same effect in various rolling processes including universal rolling. The shape of the horizontal and vertical rolls in the universal rolling of the channel steel having such parallel flanges is not limited to the embodiment shown in FIG. 6, and the shapes of the horizontal roll and the vertical roll of the universal rolling mill in the intermediate to finishing steps are appropriately adjusted. It is possible to set.

Further, with respect to the fixed outer flange channel steel according to the present invention, when a flange perpendicularity defect occurs during rolling,
Thereafter, it is also possible to keep the size within the range of the present invention by a straightening means such as a press.

[0078]

As described above, according to the present invention, it is possible to provide a constant outer flange groove steel having a constant outer flange without any quality defects such as poor flange perpendicularity and unevenness in the inner width of the web, which is a hindrance in the manufacturing process of the rectangular steel tube column. The invention is economical and extremely industrially valuable in that it provides a method for efficiently and economically producing a parallel flanged channel steel with a constant external method that can be supplied to the market and has excellent quality. It is.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an externally fixed parallel flange channel steel.

FIGS. 2 (a) to 2 (d) are schematic explanatory views respectively showing process examples of a method of manufacturing a column member using a parallel flange channel steel according to the present invention.

FIGS. 3 (a) and 3 (b) are explanatory diagrams of an example of a flange perpendicularity defect. FIG.

4 (a) to 4 (d) are explanatory diagrams of a trouble example I at the time of assembling and welding a rectangular steel pipe column.

FIGS. 4 (a) to 4 (c) are explanatory diagrams of a trouble example II at the time of assembling and welding a rectangular steel pipe column.

FIG. 6 is a schematic explanatory view showing an example of steps of a method of rolling an externally fixed parallel flange channel steel according to the present invention.

FIGS. 7 (a) and 7 (b) are explanatory diagrams of a cause of occurrence of breakage in a flange in a finishing universal rolling mill.

FIGS. 8 (a) and 8 (b) are explanatory views of the cause of the occurrence of outside flange breakage in a finishing universal rolling mill.

Claims (6)

[Claims] An external method manufactured by subjecting a rolled material to rough rolling, then to intermediate rolling, and finally to finishing rolling using a finishing universal rolling mill incorporating a split horizontal roll capable of changing the width online. An external method for a square steel tubular column having a built-in diaphragm, wherein a constant parallel flange channel and a product web inner width after completion of production of the channel satisfy the following formula: Parallel flange channel steel. ｜ Product web inner width− (Nominal web height−Nominal flange thickness × 2) ｜ ≦ + 2mm 2. An external method manufactured by subjecting a rolled material to rough rolling, then to intermediate rolling, and finally to finishing rolling using a finishing universal rolling mill incorporating a split horizontal roll capable of changing its width online. A fixed parallel flange channel steel, wherein the product flange perpendicularity after the completion of the manufacturing of the channel steel satisfies the following relationship: Parallel flange channel steel. ｜ Product flange perpendicularity ｜ ≦ + 2mm 3. A rough rolling of a rolled material, then a constant web height in an intermediate rolling, and finally a finish rolling using a finishing universal rolling mill incorporating a split horizontal roll capable of changing a width online. The method of producing a parallel flange channel steel having a constant outer method, wherein the finish inner rolling mill so that the inner width of the web after the finish rolling of the channel steel and cooling to room temperature satisfy the following formula: A method for producing a constant external flange groove steel for a rectangular steel pipe column for internally processing a diaphragm, characterized in that the width of a horizontal roll is adjusted. ｜ Web inner width-(Nominal web height-Nominal flange thickness x
2) | ≦ + 2mm 4. A rough rolling of a rolled material, a constant web height in an intermediate rolling, and a finish rolling using a finishing universal rolling mill incorporating a split horizontal roll capable of changing a width online at the end. A method of manufacturing a parallel flange channel steel having a constant outer method, wherein the finish universal rolling of the finish universal rolling is performed so that the perpendicularity of the flange after finishing rolling of the channel steel and cooling to room temperature satisfies the relationship of the following formula. A method for producing a constant outward flange parallel flange channel steel for a square steel tubular column having a built-in diaphragm, characterized by setting side angles of a horizontal roll and a vertical roll. ｜ Flange perpendicularity ｜ ≦ + 2mm 5. A rough rolling of a rolled material, a constant web height in an intermediate rolling, and a finishing rolling using a finishing universal rolling mill incorporating a split horizontal roll capable of changing a width online at the end. A method of manufacturing a parallel flange channel steel having an external method, wherein the finish universal rolling in the finish universal rolling is performed so that the perpendicularity of the flange after finishing rolling of the channel steel and cooling to room temperature satisfies the relationship of the following formula. A method of manufacturing a constant external flange groove steel for a square steel tubular column having a diaphragm built therein, wherein a rolling load is adjusted. ｜ Flange perpendicularity ｜ ≦ + 2mm 6. Inspecting the dimensions and shape of a parallel flange channel steel having a constant outer method, and: | Web inner width− (nominal web height−nominal flange thickness ×
2) A method of manufacturing a square steel tubular column with a built-in diaphragm, characterized by using only a constant outer flange channel steel satisfying | ≦ + 2 mm or | flange perpendicularity | ≦ + 2 mm.