JPS6082201A - Hot rolling method of h-beam - Google Patents

Abstract

PURPOSE:To avert decrease in elongating efficiency which may arise from a change in the space between split rolls movable in the axial direction thereof with a titled method having the stage of rolling with said rolls by rolling the web part with primary and secondary universal roughing mills. CONSTITUTION:A breakdown rolling mill 12, primary and secondary universal roughing mills 14-1, 14-2, an edger rolling mill 16-1 and a universal finishing mill 18 are disposed in order shown in the figure. A web and flanges are rolled by tapered horizontal split rolls 26 having about 5 deg. flange surface of the material and vertical rolls in the mill 14-1 and the central part of the web is held in the non-rolling down state. The flange ends are rolled by horizontal split rolls 28 tapered to about 5 deg. in the mill 16-1. The unrolled down part at the center of the web is rolled by stationary rolls 30 of the mill 14-2 and partial rolling of the web ends and flange rolling are accomplished by horizontal split rolls 32 tapered to about 5 deg. and vertical rolls. Rolling by said three units is repeated to roll down the material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hot rolling I-I section steel, and more particularly to a method for hot rolling H section steel which improves yield and reduces the number of roll changes.

Generally, hot rolling of H-section steel is carried out in a process as shown in FIG. 1 (5), a3). That is, Figure 2 (2), ■.

The materials for the slab 2, rectangular steel piece 4, steel piece 6 for H-beam steel, etc. shown in Figure 3, as shown in Figure 3, are made into open hole type 8 or closed hole type 1 shown in
The material is roughly shaped into a predetermined shape using a double breakdown rolling mill 12 having upper and lower rolls with 0 stamped thereon. The breakdown rolling mill 12 uses a plurality of hole shapes and sequentially processes the material into a shape suitable for subsequent intermediate rolling by rolling each of the plurality of buses.

The rough-shaped material is processed through one or more rough universal rolling mills 14 in the form of rolls as shown in FIG. 4 and one or more edger rolling mills 1 in the form of rolls as shown in FIG. 4(B).
6 After intermediate rolling in one bus or multiple buses, finish universal rolling mill 1 with roll shape as shown in FIG.
At step 8, H-shaped steel products are rolled into rolling mills in one pass.

Once the product dimensions are determined, the roll dimensions of the finishing universal rolling mill 18 and the roll dimensions of the previous rolling mills are determined. In other words, (a) of the prisoner in Figure 3, (b) of Figure 4 (5), and (b) of Figure 4
The dimensions of () and (c) in the figure and (b) of Fig. 4 are designed to be approximately equal. In order to limit the shape change especially after breakdown rolling, horizontal rolls of a specific width are used, so in the past it was necessary to replace the horizontal rolls every time the product dimensions changed. .

Normally, rolling of H-shaped steel is a multi-size, small-volume rolling, for example, the product size of H-shaped steel is 33 series according to ld'
There are 44 series according to ASTM standards, totaling 77 series. Conventionally, it usually takes 25 to 30 minutes to change rolls from one size to another, so in order to roll multiple sizes of II section steel, it takes roll change time proportional to the number of sizes. The operating rate is decreasing. Naturally, even when the rolls are replaced, the material must be kept warm in the heating furnace, resulting in a large amount of energy loss.

Conventionally, in H-shaped steel rolling, as shown in FIG. 5, the side surface portion 22 of the horizontal roll 20 of the rough universal rolling mill 14 wears out as the number of rolls rolled increases, and the inner width dimension of the horizontal roll 20 decreases. Tend. The vertical rolls 24 also wear out, but in this case, the opening degree of the vertical rolls 24 can be adjusted by the amount of wear, and there is no problem. For this reason, the sixth
As shown in the figure, if the flange thickness (E) is kept constant, the web height (E) will be lowered by the amount of wear on the side surface 22 of the horizontal roll 20, so usually the flange thickness (E) is increased as much as the dimensional tolerance allows. web height).

In other words, since the web height of the material is affected by the width of the horizontal roll 20, the web height
The effective roll width to be used is determined within the dimensional tolerance of
．． 0 m, ±4.0 m for 400 fins or more and less than 600 mm
Om, ±5. The tolerance of Ofl is specified in JIS G3192.

Therefore, the flange thickness varies depending on the width of the horizontal roll 20 used, and especially if the product is rolled with a worn horizontal roll 20 whose width is reduced, the flange thickness of the product will be thick and the yield will be reduced. Naturally, the cross-sectional dimensions of the product vary depending on the rolling chance due to changes in the width of the rolls used for each rolling chance.
2. There is no change in flange thickness due to wear.
These are not preferable in terms of dimensional accuracy.

In addition, it is necessary to have breakdown rolls, rough 22 pars rolls, edger rolls, and finishing universal rolls for each size, so there is the problem that the number of rolls inevitably increases, and usually there are spare rolls for each size. 2
I own ~3 sets. Furthermore, for example, if a product with a web height between 700 m and 800 m is required, it is impossible to manufacture the roll outside the existing roll width.

If it is to be manufactured, it will be necessary to newly stock breakdown rolls, color universal rolls, and edger rolls, and it is unavoidable that the number of rolls in stock will further increase.

To solve this problem, there is a conventional method, as disclosed in Japanese Patent Publication No. 53-40949, in which a horizontal roll of a universal roll is divided into two parts in a direction perpendicular to the roll axis, and a spacer is inserted between them for rolling. However, although this method can be used for a certain range of web sizes, a dedicated spacer is required for each rolling size, and although the width of the horizontal roll at the start of rolling can always be kept constant, the side wall of the horizontal roll during rolling The roll width cannot be adjusted according to the amount of wear on the part 22, and the same
The uneven thickness of the flange of the rolled product in the rolling machine remains an unresolved problem.

Furthermore, since the roll width is set not within the rolling line but at a dedicated roll exchange location away from the line, there are numerous drawbacks such as the unavoidable loss of roll exchange time required for each size change.

The problems with the conventional method are (a) in Figure 3 (2) and 1 in Figure 4.
This occurs because the dimensions of (c) in (c) in (c) in (b) in FIG. Therefore, if it is possible to change the dimensions (a), (b), (c), and (c) above within the rolling line, the inventors believe that (a), (b), and (c),
It was discovered that the above-mentioned problem could be solved by changing the dimensions of the material and rolling it, and based on this knowledge, the patent application No. 58-007542 (hereinafter referred to as the prior art) was filed.
disclosed. That is, Figure 7 Prisoner, [3].

As shown in 0, split rolls whose axial positions can be changed are used in a rough universal rolling mill (5) and an edger rolling mill [F]).
By arranging the finishing universal ratio rolling mill (0) to perform partial rolling of the web and rolling of the flange end, it is possible to roll different web plate sizes with the same roll, resulting in various useful effects.

In this prior art, both ends of the web and the flange are rolled in a rough universal rolling mill, then the central part of the web and the flange ends are rolled in an edger rolling mill, and after rolling of both is repeated, finishing is carried out in a finishing universal rolling mill. did. When the edger rolling mill partially rolls the unrolled central part of the rough universal rolling mill, the width of the rolled metal increases, so that the inner width of the web of material increases. Therefore, in response to the increase in web width, during repeated rolling, the distance between the axially movable rolls of the rough universal rolling mill and the edger rolling mill is increased to achieve the target web height. This prior application technology had many effects compared to conventional rolling, such as a reduction in the frequency of roll replacement, but one drawback was the decrease in stretching efficiency due to the change in the interval between the axially movable rolls in the above-mentioned repeated rolling. Met.

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned conventional techniques in hot rolling of H-shaped steel, and to provide an H-shaped steel that can reduce the frequency of roll changes, reduce the number of rolls owned, and improve product dimensional accuracy and stretching efficiency. The present invention provides a method for hot rolling steel.

As a result of various studies on partial rolling of section steel, the present inventors found that partial rolling of the web using two rough universal rolling mills (primary and secondary) suppresses the widening of the web and improves the stretching efficiency. I discovered that it is possible to roll the material up.

The above objects of the present invention are achieved by the following two inventions.

The gist of the first invention is as follows. That is, a method for hot rolling H-beam steel comprising the step of rolling a slab, a rectangular steel billet, a steel billet for H-beam steel, etc. as raw materials using split rolls whose position in the roll axis direction is variable for each pass. , a step of repeating partial rolling of both sides of the web by the split rolls in the primary rough universal rolling mill and flange rolling by the split rolls and vertical rolls, and a step of repeating flange end rolling by the split rolls in the edger rolling mill. and a step of repeating partial rolling of the unrolled part at the center of the web in a secondary set universal rolling machine, partial rolling and flange rolling of the web ends by the dividing rolls and vertical rolls, and the dividing in the finishing universal rolling mill. A method for hot rolling a section II steel, comprising a step of finish rolling using rolls and vertical rolls.

The gist of the second invention is as follows. That is, I (hot rolling of section steel) comprises a step of rolling slabs, rectangular steel pieces, steel pieces for H-section steel, etc. as raw materials using split rolls whose axial positions are variable for each pass. The method includes the steps of repeating partial rolling on both sides of the web by the split rolls in a primary rough universal rolling mill and flange rolling by the split rolls and vertical rolls, and unrolling the center of the web by fixed rolls in a secondary rough universal rolling mill. A step of repeating partial rolling of the lower part, flange rolling with the split rolls and vertical rolls, and rolling of the flange end with the split rolls, and a stage of finish rolling with the split rolls and the vertical rolls in a finishing universal rolling mill. This is a hot rolling method for II section steel characterized by the following.

In the first invention, the arrangement of the rolling mills in the present invention is as shown in FIG.
-1. The secondary roughing universal mill 14-2 and the finishing universal mill 18 are arranged in this order, but in the second invention, as shown in FIG. The layout is such that 1 is omitted.

Next, the divided roll used in the present invention will be explained.

Primary roughing universal rolling mill 14 for both the first invention and the second invention
As shown in Fig. 9, the horizontal roll 1 is composed of two divided rolls 26 of a constant width divided perpendicular to the roll axis, and the position of these divided rolls 26 can be changed symmetrically in the roll axis direction. Yes, it is the same as in the case of the rough universal rolling mill of the prior art. The change in the position of the roll axis is based on a patent application filed in 1982.
-134435, Patent Application No. 57-134436, Japanese Patent Application No. 57-134437, and the like are used.

Next, the edger rolling mill 16-1 of the first invention uses two divided rolls 28 that are variable in the axial direction, as shown in FIG. As shown in FIG. 11, the horizontal rolls of the secondary rough universal rolling mill 14-2 of the first invention include a roll 30 fixed integrally with a shaft at the center of the web width, and two rolls on both sides of which the axial position is variable. Consisting of split rolls 32,
The split rolls 32 can be moved symmetrically in the roll axis direction, but the flange ends cannot be rolled. On the other hand, the secondary rough universal rolling mill 14-2A of the second invention is
As shown in Figure 2, it has a roll 30 which is fixed integrally with the shaft at the center of the web width, and split rolls 32A on both sides of which the position can be changed symmetrically in the roll axis direction, and has a configuration that also allows flange end rolling. It has become. The finishing universal rolling mill 18 in both inventions uses two axially variable split rolls with almost no taper as shown in FIG. 7 (O) of the prior art.

Next, rolling using the roll of the present invention having the above configuration will be explained. First, in the first invention, in the primary rough universal rolling mill 14-1, the web and flange are rolled using horizontally divided rolls 26 and vertical rolls in which the flange surface of the material has a taper of about 5 degrees, and the central part of the web is in an unrolled state. shall be. 'Next, in the edge rolling mill 16-1, a horizontally divided roll 2 having a taper of about 5 degrees at the flange end is rolled.
8. Roll the flange end. Next, in the secondary rough universal rolling mill 14-2, the unrolled part at the center of the web is rolled with a fixed roll 30, and the end part of the web is partially rolled and flanged with a horizontal split roll 32 having a taper of about 5 degrees and a vertical roll. . The material is rolled down by repeating rolling by these three machines. However, in this case, the relationship between the roll interval (G) of the horizontally divided rolls 26 in FIG. 9 and the width (A) of the fixed roll 30 in FIG. 10 is always K(A)t'1())
It is necessary to roll it in a very large condition. After completing these intermediate rolling steps, the split rolls 26 as shown in Fig. 9 are finished, with the outer horizontal rolls and the vertical rolls having almost no taper.The universal rolling mill 18 is used to raise the flanges with a 5-degree taper to finish the product. Let's go.

As described above, the first invention has different web heights by adjusting the roll spacing of the split rolls 26, 28, and 32 shown in FIGS. 9, 10, and 11 and the split rolls of the finishing universal rolling mill. The 11 section steel
By adjusting the interval between the upper and lower rolls of the split rolls 28 of the rolling mill 16, H-beams with different flange widths can be rolled with the same roll without changing rolls.

Next, in the second invention, as in the first invention, first, in the primary rough universal rolling mill 14-1, a horizontally divided roll 26 whose flange surface of the material has a taper of about 5 degrees is used.
The web and flange are rolled with vertical rolls, leaving the center of the web unrolled.

Next, in the secondary rough universal rolling mill 14-2A, the flange end is simultaneously rolled by a horizontally split roll 32A having a taper of about 5 degrees at the flange end.
2A and the vertical roll roll the flange, and the fixed roll 30 rolls the unrolled part at the center of the web, and these two rollings are repeated to roll down the material. However, in this case, the relationship between the roll spacing (G) of the horizontally divided rolls 26 in FIG. 9 and the width (A) of the fixed roll 30 in FIG. There is.

Further, the width of the vertical rolls shown in FIG. 12 must be smaller than the flange width of the material sent to the finishing mill. Also split roll 3
2A does not necessarily have to be a reduction at the web end of the material. After completing the intermediate rolling in these primary and secondary rough universal rolling mills, the finishing universal rolling mill 18 with split rolls 26 as shown in FIG. Finish the product by raising the flange with a taper.

The second invention is the split roll 2 shown in FIGS. 9 and 12 as described above.
By adjusting the spacing between the split rolls of 6, 32A and the finishing universal roll rolling mill 18, it is possible to roll H-beams with different web heights using the same roll without replacing the rolls.

Also, 1st. Horizontal roll 2 shown in FIG. 5 also in the second invention
Even if the side wall portion 22 of the roller 1 is worn, by widening the interval between the rolls of the split rolls 26 according to the amount of wear, a product with a constant web height and flange thickness can be manufactured with high stretching efficiency.

Here, the differences between the rolling method shown in the prior art and the method of the present invention will be compared and explained. The difference between the two exists in the process of the secondary rough universal rolling mill 14-2.14-2A. That is, in the rolling method of the prior art, as shown in FIG. 7, after rolling down both ends of the web and the flange (5), rolling is repeated in which the unrolled central part of the web and the flange end are rolled down (B) in the edge rolling mill 16. . Since the width of the web is widened during non-rolling center rolling in this edger rolling mill 16, in this method, during rolling of a certain size, the inner width of the web increases with each coarse universal rolling bus. Accordingly, the distance between the axially movable rolls in the coarse rolling mill 14 and the edge rolling mill 16 must be increased to achieve the target web height. Naturally, the stretching efficiency will decrease due to the widening of the web. On the other hand, in the method of the present invention, since a secondary rough universal rolling mill is installed, the width expansion during rolling of the non-reduced central part of the web is restrained by the vertical rolls. The interval between the axially movable rolls of the rolling mill can be maintained substantially constant during rolling of one size. Therefore, compared to the prior art, the present invention eliminates the need to adjust the interval between axially movable rolls for each bus, improves the area reduction efficiency of the web and flange, and improves the stretching efficiency. I can do it.

Example 1 One roll having the dimensions shown in Table 1 was used and the nominal size was 700×3 with the same roll without changing the roll in the first invention.
00 and 900X300 H-beams were manufactured. That is,
Figure 13 (A), (B), (C) shows the case of 700X300.
1', G)), the case of 900X300 is shown in Figure 14, (
Bl, (C) and ([), but in any case, as shown in (2), the primary rough universal rolling mill 14
-1, both sides of the first table except the center of the flange and web are rolled down, then the edges of the flange are rolled down with an edger rolling mill 16-1 as shown in [F]), and then the flange ends are rolled down as shown in 0. The unrolled part at the center of the web and the flange are rolled down in the secondary rough universal rolling mill 14-2, and after this step is subjected to multiple bus rolling using reversible rolling, the finishing universal rolling mill 14-2 is used to roll the flanges in one pass. It was an H-shaped steel product.

700X300 and 900X rolled in this way
300 I-1 section steel has a surface condition with no scratches during the primary and secondary rough universal rolling and no scratches at the boundary between the rolling part during the 1/2 lower part and the edge rolling. The results were good, web buckling did not occur, the dimensional accuracy was good due to fine adjustment of the position of the variable position split roll against wear, and the yield was excellent.

Also, Fig. 13 (A), CB), (C1, CD) and Fig. 14 (A), Q3+.

Compare with 0.0 [7] The latter is split roll 2 of (5)
6 and ■ divided roll 2B and 0 divided roll 32 and 0
Since the distance between each of the divided rolls 34, etc. of the former was only increased by 194 fins, switching from 700 x 300 to 900 x 300 was only an online change in the position of the divided rolls, and there was no need to replace the rolls. Also, Figure 13 (support).

03 + C), (QI) Method T700
250 was also rolled.

Example 2 Using rolls with the dimensions shown in Table 2, according to the second invention, the nominal size was 700X with the same roll without replacing the rolls.
300 and 900×300 H-beams were manufactured. In other words, in the case of 700X300, Table 2, Figure 15 (5), ([3), (C1,900X3
00 cases are shown in Fig. 16 (A), ([3), and (C), but in any case, as shown in (2), the flange and web are rolled in the primary rough universal rolling mill 14-1. Both sides except the center are rolled down, and then the non-Fk lower part of the center of the web, the flange ends, and the flange thickness are rolled down in the secondary rough universal rolling mill 14-2A as shown in ■, and this process is rolled in multiple passes using reversible rolling. Thereafter, the flange was tapered in one bath of the finishing universal rolling mill 18 to obtain an H-shaped W4-shaped product. 70 rolled in this way
0X300 and 900X300 H-shaped steels have good surface conditions, with no flaws at the boundary between the unrolled part and the rolled part during primary and secondary rough universal rolling, or flaws during finish universal rolling, and no web buckling. This did not occur, and the dimensional accuracy was good and the yield was excellent due to the fine adjustment of the position of the variable position split roll against wear. In addition, since there is no widening of the web in the secondary rough universal rolling mill 14-2A, 1
Next, during the repetition of the secondary rough universal rolling, there was no need to adjust the interval between the axially movable rolls, and the rolling efficiency was excellent. Also, Figure 15 Prisoner, (Bl, (C) and Figure 16 (2), [F])
, 0, the latter has the divided roll 26 of (2), the divided roll 32A of [F]), and the divided roll 34 of 0.
Since the distance between each of the two rolls is 194 mm wider than the former, switching from 700 x 300 to 900 x 300 requires only an online change in the position of the split rolls, and there is no need to replace the rolls.

In both Example 1 and Example 2, the number of roll replacements was significantly reduced to about 173 compared to the conventional method, the number of rolls held was reduced, and the heating time of the material was also shortened.

As is clear from the above embodiments, the present invention uses split rolls whose axial positions are variable in a primary roughing universal rolling mill, an edger-m rolling mill, a secondary roughing universal rolling mill, a finishing universal rolling mill, etc. By rolling with 1M degree of roll change, reduction in the number of rolls owned, improvement in dimension f[ and yield, reduction in heating energy consumption, and improvement in rolling efficiency, we were able to achieve many effects. .

[Brief explanation of drawings]

Figures 1 and (B) are both H-shaped steel hot rolling process diagrams, Figure 2 is a cross-sectional diagram showing the shape of the hot-rolled material, and (C) is H-shaped steel. Figure a3) is a cross-sectional view of the roll showing the shape of the holes; (0 is a cross-sectional view showing the process of hot rolling of H-beam steel,
Fig. 5 is a sectional view showing wear on the side surface of a conventional universal rolling mill horizontal roll, Fig. 6 is a sectional view showing the dimensions of an H-beam, and Fig. 7 (2), CB), (C1 are all Rough universal rolling mill surface of prior technology, two-jar rolling mill (13)
and Finishing universal rolling mill (0), Fig. 8 (2), (81 is a process diagram showing the hot rolling of the I-1 section steel of the present invention; , 0 indicates the second invention. Fig. 9 is a sectional view showing the o single layer shape of the primary rough universal rolling mill according to the embodiment of the invention, and Fig. 10 is the Edger-Ell rolling type roll according to the embodiment of the first invention. 11 is a cross-sectional view showing the roll shape of the secondary rough universal rolling mill of the first embodiment of the invention;
Figure 2 is a sectional view showing the roll shape of the secondary rough universal rolling mill of the second embodiment of the invention, and Figure 13 (2), ([3), (
C1, ■) are both 700 X 3 according to the first invention
00 Cross-sectional view showing the rolling process of an example of H-beam steel, No. 14
Figures (2), ([3). 0, O) are both 900X3001- according to the first invention
A cross-sectional view showing the rolling process of an example of I-beam steel, Figure 15 (5
), (13+, (0 is 7 according to the second invention)
A cross-sectional view showing the rolling process of an example of 00X300H section steel,
FIG. 16(5), 03) (O is a sectional view showing the rolling process of the 900 x 3 o O)-T section steel according to the second invention. 12...Breakdown rolling mill, 14-1...1st set uninoku-saru rolling mill, 14-2
．． 14-2A...Second set uninoku-saru rolling mill, 16
-1...Edgeer rolling mill, 18...Finishing universal rolling mill, 26...Divided roll (primary set Uni-(for -Sal rolling mill), 28...Divided roll (Edgeer rolling machine) ), 3
0...Fixed roll (for secondary set Uni-Cusal rolling mill)
, 32. 32A... Split roll (secondary set Uni (for -Sal rolling mill), 34... Split roll (for Finishing Uni-no-Kuichi Sal roll mill). Agent: Patent attorney Takeo Nakaji Figure 1 (B) (B) Figure 2 Chung Figure 3 (A) (Mark Figure 4 Figure 51!1 Figure 71!1 Figure 8 (A) (8) Figure 9 Figure 10 Figure 12 Figure 131゛η Figure 14 Country 15

Claims (2)

[Claims] (1) Hot rolling of H-beams made of slabs, rectangular billets, steel billets for H-beams, etc., which has a stage of rolling using split rolls whose position R in the roll axis direction is variable for each bus. The rolling method includes the steps of repeating partial rolling on both sides of the web by the split rolls in a primary rough universal rolling mill and flange rolling by the split rolls and vertical rolls, and flange end rolling by the split rolls in an edger rolling mill. repeating partial rolling of the unrolled part of the center of the web by fixed rolls in a secondary rough universal rolling mill, partial rolling and flange rolling of the web ends by the split rolls and vertical rolls, and finishing universal rolling; A step of finish rolling using the dividing roll and vertical rolls in the machine.
Hot rolling method for section steel. (2) Hot rolling of H-beam steel, which involves rolling slabs, rectangular steel slabs, H-beam steel slabs, etc., using split rolls whose positions in the roll axis direction are variable for each pass. The method includes the steps of repeating partial rolling on both sides of the web by the split rolls in a primary rough universal rolling mill and flange rolling by the split rolls and vertical rolls, and unrolling the center of the web by fixed rolls in a secondary rough universal rolling mill. A step of repeating partial rolling of the lower part, flange rolling with the split rolls and vertical rolls, and rolling of the flange end with the split rolls, and a stage of finish rolling with the split rolls and the vertical rolls in a finishing universal rolling mill. A method for hot rolling H-section steel, characterized by: