JP3279222B2 - Rolling method of shaped steel with flange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling method for freely adjusting the web height of a section steel having a flange, such as an H-section steel, during rolling.

[0002]

2. Description of the Related Art A facility for producing a section steel having a flange such as an H section steel is generally as shown in FIG. The raw steel slab that has exited the heating furnace is first shaped and rolled by a breakdown rolling mill BD, which is a double rolling mill, into a shape suitable for target product dimensions. Subsequently, in the coarse universal rolling mill groups R1 and R2 including the coarse universal rolling mills U1 and U2 and the edger rolling mills E1 and E2, the thickness is reduced and the flange end is formed. further,
The flange is formed so as to be perpendicular to the web by the finishing universal rolling mill F, and an H-shaped product is obtained.

As shown in FIG. 6, the dimensions of an H-section steel obtained by the conventional universal rolling method are as follows, assuming a web height H, a web inner width LH, and a flange thickness t2.
LH + 2 × t2. Since the web inner width LH is substantially the same as the horizontal roll width of the finishing universal rolling mill F, the web height H is
Is determined by the horizontal roll width and the flange thickness. For this reason, for example, an H-section steel in which the web height is constant irrespective of the amount of change in the flange thickness, and conversely, an H-section steel in which the flange thickness is constant and the web height can be arbitrarily set, have been sought. In this case, it is necessary to prepare the horizontal roll width of the rough universal rolling mill and the finishing universal rolling mill in accordance with the size of the H-beam to be rolled. Therefore, the increase in the number of dimensional sizes to be rolled regardless of the flange thickness t2 or the web inner width LH means that each time the number of rolls is increased and the dimensional size to be rolled is changed, the width of the width that matches the size is changed each time. It is necessary to change to a horizontal roll, and the operation rate is greatly reduced.

As a technique for solving such a problem, there is a method disclosed in Japanese Patent Application Laid-Open No. 4-288902.
This is, as shown in FIG. 8, a breakdown rolling mill BD,
Rough universal rolling mill U1, U2, edger rolling mill E
A rolling mill Y comprising a pair of upper and lower rolling rolls with adjustable roll widths is arranged close to the rear surface of an edger rolling mill E2 of a normal H-section steel hot rolling facility consisting of a general rolling mill 1, E2 and a finishing universal rolling mill F. The rolling equipment installed is used. The rolling method is as shown in FIG.
A step of forming excess material at the base of the flange and the web and at both ends of the web is performed by a coarse universal rolling mill.
Subsequently, by setting the roll width larger than the inner width of the web in the rough universal rolling process in a rolling mill Y equipped with a pair of upper and lower rolling rolls whose roll width is adjustable, the mechanical web due to the roll width difference is obtained. As the inner width is increased, a process is performed in which most of the reduced area is converted into an enlarged inner width of the web by rolling the excess portion. By repeating these two steps, the inner width of the web is increased until a predetermined web height is obtained. This technique enables a large change in the web height by repeating the formation of the excess thickness and the mechanical expansion of the inner width of the web, but has the following problems.

[0005]

At the stage of changing the height of the web, the thickness of the web and the flange is close to the thickness of the product. When a large change in the web height is performed, it is necessary to repeat the formation of the excess thickness and the expansion of the inner width of the web, so that it takes a long time to change the web height, and the temperature drop between the web and the flange increases. If the temperature of the material to be rolled becomes too low, it becomes difficult to continue the rolling due to an increase in the rolling load or the like, so that the inner width of the web cannot be increased for a long time.

[0006] Also, since the web of the H-section steel is usually thinner than the flange, the temperature drop of the web is faster than that of the flange. The difference increases. As a result, in the cooling process after rolling, the amount of shrinkage in the length direction of the flange becomes larger than that of the web, and compressive residual stress is generated in the web. The greater the temperature difference, the greater the residual stress due to this compression, eventually causing buckling and waving of the web. It is extremely difficult to correct the corrugated product and it cannot be shipped as a product.Therefore, especially for products with thin webs, rolling must be performed so that the temperature difference between the web and the flange does not increase. It was problematic to make the time required to increase the inner width extremely long. For the above reason, the number of repetitions of the web inner width cannot be increased so much, and as a result, the upper limit has to be set for the amount of expansion of the web inner width.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is intended to reduce the rolling time in the rough universal rolling process, reduce the temperature drop between the web and the flange, and reduce the temperature difference between the two. It is an object of the present invention to provide a method of rolling a section steel capable of obtaining a larger amount of inner width of a web.

[0008]

According to the present invention, there is provided a method for rolling a section steel having a flange, comprising: a rolling mill comprising a group of coarse universal rolling mills comprising a coarse universal rolling mill and an edger rolling mill; and a finishing universal rolling mill. In the method of rolling a section steel having a flange by using, the rough universal rolling mill group, having a roll shape capable of forming excess thickness at the flange of the material to be rolled and the root of the web and both ends of the web, roll A width having at least one width-fixed coarse universal rolling mill incorporating a fixed horizontal roll, and a width having at least one variable width coarse universal rolling mill incorporating a horizontal roll whose width can be adjusted; By setting the roll width of the variable coarse universal rolling mill to be substantially the same as the roll width of the fixed width coarse universal rolling mill, The process of repeating the reduction of the thickness of the flange and the web of the material to be rolled to form extra portions at the roots of the flange and the web and at both ends of the web; and the material to be rolled after the rough universal rolling is completed. By rolling the roll width is set to be larger than the roll width of the width fixed coarse universal rolling machine in the width variable coarse universal rolling mill, along with the mechanical web inner width expansion due to the roll width difference, Rolling the excess portion by converting most of the reduction in surface area of the excess portion to an increase in the inner width of the web, and performing a step of performing several passes while setting the roll width to one or more. It is characterized by the following.

In order to obtain a larger width of the inner width of the web, after the above-mentioned rolling step is completed, a vertical roll is formed by the above-mentioned fixed width universal rolling mill so as not to lower the flange of the material to be rolled. A roll gap between the horizontal roll side walls is opened, and the web of the material to be rolled is rolled only with the upper and lower horizontal rolls, thereby reducing the thickness of the web and forming excess portions at both ends of the web, In the width-variable coarse universal rolling mill, by setting the roll width to be larger than that of the previous stage and rolling the excess portion,
Rolling for further expanding the inner width of the web includes performing one pass or several passes while repeating these two processes. In the web inner width expanding step, the vertical roll of the variable width coarse universal rolling mill is opened to a position where the flange of the material to be rolled is not lowered. This is because the extension in the length direction (rolling direction) of the surplus portion due to rolling is regulated by the flange, and most of the reduction in the surface area of the surplus portion is converted to increase in the inner width of the web.

(1) Configuration of Rolling Line (See FIG. 1) In the present invention, two or more coarse universal rolling mills are installed in a group of coarse universal rolling mills in a rolling line,
At least one of the coarse universal rolling mills
A horizontal roll having a fixed width is used which is capable of forming a margin at a flange portion of the material to be rolled, a root portion of the web, and both end portions of the web. Hereinafter, this coarse universal rolling mill is referred to as a “width fixed coarse universal rolling mill”. In addition, a horizontal roll whose width can be arbitrarily adjusted is used for at least one rough universal rolling mill. Hereinafter, this coarse universal rolling mill is referred to as a “width-variable coarse universal rolling mill”.

(2) Rolling Method Coarse Universal Rolling Step (See FIG. 2) The horizontal roll width of a variable width coarse universal rolling mill incorporating a horizontal roll whose roll width is adjustable, and a horizontal roll having a fixed roll width are incorporated. The width of the web and flange is reduced by two coarse universal rolling mills, and the remaining width is approximately the same as the horizontal roll width of the fixed width coarse universal rolling mill. Form a meat part. At the same time, the edge of the flange is reduced by an edger rolling mill in the same manner as in the prior art to control the flange width.

Web inner width expanding step (see FIGS. 3 and 4) After the coarse universal rolling step, the horizontal roll width of the variable width coarse universal rolling mill is set wider than the horizontal roll width of the fixed width coarse universal rolling mill. . By rolling in this state, the inner width of the mechanical web is expanded by the difference in roll width, and at the same time, most of the reduced surface area is converted to an increase in the inner width of the web by rolling the excess portion, and the inside of the web is expanded. Increase width. When the inner width of the web is further increased, the inner width of the web is increased in the first pass of the inner width of the web without reducing the excess portion to the thickness of the central portion of the web.
In the following second pass, the horizontal roll width of the variable width coarse universal rolling mill is set wider than in the first pass and rolling is performed in the opposite direction, and the inner width of the web is enlarged again.

In order to obtain a larger width, the roll gap between the vertical roll and the horizontal roll side wall is opened so as not to roll the flange of the material to be rolled in the subsequent rolling by the fixed width coarse universal rolling mill. In addition, the web of the material to be rolled is rolled only by the upper and lower horizontal rolls to reduce the thickness of the web, and excess portions are formed at both ends of the web. Further, in the third pass, the excess height formed in the second and third passes of the fixed width coarse universal rolling mill is reduced by a variable width coarse universal rolling mill in which the roll width is further adjusted, and the web height (web height) is reduced. (Inner width).

(3) Principle of Solving the Problems of the Prior Art In the variable width coarse universal rolling mill, the thickness of the web and the flange is reduced simultaneously with the fixed width coarse universal rolling mill in the coarse universal rolling process. The thickness can be reduced by the two coarse universal rolling mills, and the time of the coarse universal rolling step is greatly reduced. In addition, in the web inner width expanding step, the width of the horizontal roll of the width variable coarse universal rolling mill is adjusted to increase the web inner width, so that a conventional rolling mill is installed without installing a dedicated rolling mill as in the conventional case. The inside width of the web can be expanded. As described above, since the rolling time in the rough universal rolling step can be reduced, the temperature drop of the material to be rolled is reduced, and the increase in the rolling load can be suppressed, particularly because the web temperature is maintained at a high temperature. The temperature difference between the flange and the web is reduced, so that the web does not undulate in the cooling process after rolling. As a result, it is possible to significantly change the inner width of the web, which is impossible with the conventional method.

[0015]

FIG. 1 is a configuration diagram showing an example of a rolling line for carrying out the present invention. Here, the group of coarse universal rolling mills is a width variable coarse universal rolling mill U1 incorporating a horizontal roll 11 having a fixed roll width, an edger rolling mill E, and a variable width incorporating a horizontal roll 21 having an adjustable roll width. The rough universal rolling mill U2 is arranged in this order. The raw steel slab heated in the heating furnace is rolled by a breakdown rolling mill BD into a shape suitable for the subsequent rough universal rolling. This outline H
As described below, the material 1 to be rolled is subjected to coarse universal rolling and the expansion of the inner width of the web in the above-mentioned group of coarse universal rolling mills. Note that, as the material to be rolled 1 to be charged into the group of coarse universal rolling mills, a rough shaped steel slab formed by a continuous casting machine or the like can be used.

FIG. 2 shows an outline of the rough universal rolling step of the present invention. 2, there is almost as same as the horizontal roll width RH ₁ of the horizontal roll width RH ₂ is fixed width rough universal rolling mill U1 width variable rough universal rolling mill U2.
By performing the coarse universal rolling under the setting of such a roll width, two rough universal rolling mills U1,
Using U2, the thickness of the web and the flange is reduced twice in one pass, so that the rough universal rolling can be performed with less than half the number of passes compared to the case of one. As a result, the rolling time can be reduced, so that the temperature drop between the web and the flange is reduced, and the temperature difference between the two at the end of the rough universal rolling can be suppressed to a small range.
In the rough universal rolling process, the edger mill E reduces the flange end in the same manner as in the prior art, and controls the flange to a target width. The horizontal roll ends of the fixed width coarse universal rolling mill U1 are shaped so as to form excess portions 2 at the base of the flange and the web of the material 1 to be rolled and at both ends of the web, as shown in FIG. Width a, height b
Is formed. Here, the surplus amounts a and b are determined in consideration of the expansion amount of the inner width of the web and the stability of rolling in the subsequent process.

After the rough universal rolling is completed, the inner width of the web is subsequently increased. FIG. 3 shows an outline of the step of enlarging the inner width of the web in one pass, which is the first method of the present invention. After rolling final pass of the rough universal rolling is performed at fixed width rough universal rolling mill U1 and edger mill E, width horizontal roll 21 of variable rough universal mill U2 has a width fixed rough universal rolling width RH ₃ It is set to be wider than the horizontal roll width RH ₁ of the machine U1. That is, RH ₃ > RH ₁ (≒ RH ₂ ).

As described above, if the roll width is adjusted and the rolling is performed by the variable-width coarse universal rolling mill U2, the material to be rolled 1
The web is mechanically stretched due to the difference in roll width in the process of biting the web, and at the same time, the excess web 2 is rolled to convert most of the reduced surface area of the web 2 to an increase in the inner width of the web. As a result, an effective expansion of the web inner width is performed. Here, the variable width coarse universal rolling mill U2
The vertical roll 22 is opened in accordance with the adjustment amount of the horizontal roll width to a position where the flange is not lowered. This is the length direction (rolling direction) of the web surplus portion 2 by rolling.
This is because the elongation of the web is restricted by the flange, and most of the reduced area is converted into an increase in the inner width of the web. FIG.
This is because, as shown in (1), forming excess thickness at both ends of the web is more likely to prevent buckling of the web due to a difference in elongation in the longitudinal direction caused by a difference in rolling reduction of each section of the material to be rolled.

By the above-described rolling, the inner width of the web can be increased by the variable width coarse universal rolling mill U2 in the same manner as in the conventional method without installing a dedicated rolling mill. In addition, by reducing the rolling time in the coarse universal rolling process and reducing the temperature drop between the web and the flange and the temperature difference between the two, the number of passes in the web inner width enlarging process is increased to increase the web inner width. It has become possible to obtain the amount of expansion.

The material to be rolled after the expansion of the inner width of the web is conveyed to the finishing universal rolling mill F, where the flange is raised vertically to form an H-shape. Surplus part 2 in the previous process
Is rolled so that the thickness of the surplus portion is the same as the thickness of the central portion of the web in this finish universal rolling. Here, as shown in FIG. 3, the finishing universal rolling mill F whose horizontal roll width is adjustable is used to adjust the roll width so as to match the inner width of the web of the material to be rolled. Can be rolled without exchanging with the expansion amount of the inner width of the web.

In order to further increase the amount of expansion of the inner width of the web, as shown in FIG. 4, reciprocating rolling is performed in a group of coarse universal rolling mills to increase the number of times of the inner width expansion of the web.
At this time, it is necessary to increase the excess thickness at both ends of the web as compared with the case where the inner width of the web is increased in one pass, but the method is not particularly specified.

As a second method of the present invention, a method of ending the expansion of the inner width of the web in the variable width coarse universal rolling mill U2 in the second pass and performing the forming by the subsequent finish rolling step will be described with reference to FIG. . The material to be rolled after the rough universal rolling in FIGS. 4 (a) and 4 (b)
As in the case of expanding the inner width of the web in one pass, the inner width of the web is expanded by the roll width difference and the rolling of the excess portion, but the thickness of the excess portion of the material to be rolled is reduced to the thickness of the central portion of the web. Rolling is completed without leaving any excess thickness.
Subsequently, when rolling is performed in the second pass in the reverse direction, FIG.
(D) As shown in FIG.
Second horizontal roll width RH ₄ is adjusted to be wider than the web in the width (the first pass of the horizontal roll width RH ₃₎ of the material to be rolled, performs reduction of expansion and excess thickness portion of the web in the width. At this stage, if the target expansion amount of the web inner width is obtained, the edger rolling mill E and the fixed width coarse universal rolling mill U
No. 1 does not reduce the rolled material by opening the roll gap, conveys the rolled material to the finishing universal rolling mill F, and raises the flange as shown in FIG.

Unless the excess portions at both ends of the web are reduced to the same thickness as the central portion of the web at the stage shown in FIG. 4D, rolling to increase the inner width of the web is repeated in the variable width coarse universal rolling mill U2. The inner width of the web can be further increased.

As a third method of the present invention, when the inner width of the web is further enlarged, after the rolling of FIG. 4D in the second pass is completed, the edger rolling mill E is set as shown in FIG. The rolled material is passed through the rolled material in a state where the material to be rolled is not rolled by opening the roll opening at a fixed width.
Then, the central part of the web is rolled by the horizontal roll 11, and FIG.
(F) As shown in FIG.
Is formed. At this time, the vertical gap between the vertical roll 12 and the flange is not reduced. In the subsequent third pass, the edger rolling mill E opens the roll gap and passes the material to be rolled without reduction. Width variable horizontal roll width RH ₅ of rough universal mill U2 is set to be wider than the horizontal roll width RH ₄ of second pass, the vertical rolls 22 open roll gap to a position which does not pressure the flange of a material to be rolled Keep it. In this state, the same rolling as in the case of expanding the inner width of the web in one pass is performed as shown in FIG. 4 (i), and after expanding the inner width of the web, using the finishing universal rolling mill F as shown in FIG. 4 (j). Perform finishing universal rolling. If it is necessary to further increase the inner width of the web, the state returns to the state shown in FIG. 4 (h) and returns to (c). Just repeat.

As described above, in the present invention, by installing a coarse universal rolling mill capable of adjusting the horizontal roll width in the group of coarse universal rolling mills, the inner width of the web can be increased in the same manner as in the prior art, and the rough The effect that the number of rolling passes and the rolling time in the universal rolling step can be significantly reduced is obtained, so that the temperature drop of the material to be rolled can be reduced, and the temperature difference between the web and the flange can be reduced. As a result, it is possible to increase the web height larger than before.

[0026]

[Example] Web height 600 mm, flange width 300 m
For example, in the case where the inner width of the web of the H-section steel is increased,
Compare the present invention with the prior art. Using the rolling equipment of the present invention shown in FIG. 1 and the conventional rolling equipment shown in FIG. 8, a product having a web thickness of 11 mm and a flange thickness of 17 mm is rolled. The surface temperature of the web and the flange at the end was measured, and the average temperature of the web and the flange was calculated from the surface temperature and compared. In the present invention and the conventional equipment, the number of rough universal rolling mills and the number of widening rolling mills are the same. First,
In both cases, when expanding the inside width of the web by one pass,
A comparison was made. As shown in Table 1, in the method of the present invention, the number of passes of the coarse universal rolling was half that of the conventional method, and the temperature of the material to be rolled at the end of the coarse universal rolling was increased by 100 ° C. or more for both the web and the flange. The number of passes in the widening rolling mill and the finishing universal rolling mill is the same,
The temperature of the material to be rolled after the completion of these rollings was still higher than the conventional method by 80 ° C. or more in the present invention. At this time, the web inner width expansion amount was 15 mm as in the conventional method. Furthermore, in order to increase the amount of web inner width expansion,
In the case where the web inner width is increased in three passes, according to the method of the present invention, the web temperature is 689 ° C., and there is room for further expanding the web inner width.
The temperature was as low as ° C. In this case, the web inner width expansion amount was 45 mm in either method.

[0027]

[Table 1]

As described above, according to the present invention, it is possible to increase the inner width of the web without extremely lowering the temperature of the material to be rolled, and it is possible to increase the number of times of expanding the inner width of the web as compared with the related art. Was.

[0029]

As described above, according to the present invention, coarse universal rolling of a material to be rolled and enlargement of the inner width of the web are performed using a fixed width coarse universal rolling mill and a variable width coarse universal rolling mill. Therefore, the rolling time in the rough universal rolling step can be shortened, and the reduction in the temperature of the material to be rolled can be suppressed, so that the inner width of the web can be made larger than before. As a result, it becomes possible to manufacture H-section steels whose web heights vary widely over the same rolling roll, thereby reducing the number of rolling rolls and reducing the frequency of changing rolls, and because the number of passes is smaller than before. Effects such as high rolling efficiency and improved productivity can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a rolling facility used in the method of the present invention.

FIG. 2 is a view showing a rough universal rolling method in the present invention.

FIG. 3 is a view showing a rolling method for enlarging the inner width of the web in one pass in the present invention.

FIG. 4 is a diagram showing a rolling method for expanding the inner width of the web in two or more passes in the present invention.

FIG. 5 is a diagram showing a shape of a surplus portion of a material to be rolled at the end of rough universal rolling.

FIG. 6 is a sectional view showing a dimensional relationship of the H-section steel.

FIG. 7 is a configuration diagram showing an example of a conventional rolling facility.

FIG. 8 is a configuration diagram showing another example of a conventional rolling facility.

9 is a view showing a method of enlarging the inner width of the web by the rolling equipment of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Material to be rolled 2, 2a Surplus part 11 Horizontal roll of fixed width coarse universal rolling mill 12 Vertical roll of fixed width coarse universal rolling mill 21 Horizontal roll of variable width coarse universal rolling mill 22 Vertical roll of variable width coarse universal rolling mill BD Breakdown rolling mill U1 Fixed width universal rolling mill U2 Variable width coarse universal rolling mill E Edger rolling mill F Finishing universal rolling mill

Continued on the front page. (72) Takashi Ariizumi, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Masamasa Kamata 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan stock In company

Claims (3)

(57) [Claims] 1. A method of rolling a section steel having a flange by using a rolling facility including a group of coarse universal rolling mills comprising a coarse universal rolling mill and an edger rolling mill and a finishing universal rolling mill, The machine group has at least one width-fixed coarse universal rolling mill having a roll shape capable of forming excess material at the flange of the material to be rolled, the root of the web, and both ends of the web, and incorporating a horizontal roll having a fixed roll width. And at least one variable-width coarse universal rolling mill incorporating a horizontal roll whose roll width is adjustable, and the roll width of the variable-width coarse universal rolling mill is set to the width of the fixed-width coarse universal rolling mill. By performing rough universal rolling with the width set to be almost the same as the width, the flange and web of the material to be rolled are repeatedly reduced in thickness. Turning over, forming a surplus portion at the base of the flange and the web and at both ends of the web, and rolling the material to be subjected to the rough universal rolling, the roll width in the width variable coarse universal rolling mill, the roll width By setting the roll width to be larger than the roll width of the width-fixed coarse universal rolling mill, the internal width of the web is mechanically increased due to the roll width difference, and the excess wall portion is reduced by rolling the excess wall portion. A step of performing rolling for converting most of the above into an increase in the inner width of the web by one pass or several passes while setting the roll width to be larger. 2. The roll gap between the vertical roll and the horizontal roll side wall is opened in the width fixed coarse universal rolling mill so as not to reduce the flange of the material to be rolled, after the end of the rolling step according to claim 1. In advance, by rolling the web of the material to be rolled with only the upper and lower horizontal rolls, while reducing the thickness of the web, forming a surplus portion at both ends of the web, the width variable coarse universal rolling mill A step of rolling the excess width portion by setting the roll width larger than that in the previous stage to further increase the inner width of the web, and performing one pass or several passes while repeating these two processes. And a method for rolling a shaped steel having a flange. 3. The method according to claim 1, wherein in the step of expanding the inner width of the web, the vertical rolls of the variable width coarse universal rolling mill are opened to a position where the flange of the material to be rolled is not lowered. Rolling method of shaped steel having a flange.