JPH06335713A - Roughing mill and rough rolling method for shape steel - Google Patents

Abstract

PURPOSE:To reduce the dispersion the cross-sectional shape of flange in the rolling direction of a material to be rolled by material drawing of the flange in accordance with rolling down of the web and roll shapes having the flange excellent in dimensional accuracy. CONSTITUTION:A rolling roll 30 which consists of an arbor 10, projecting part 12 which is arranged on the arbor 10 and has the cross-sectional shape by which the inside of flange and web of the material to be rolled are rolled down and sleeves 20, 20 which are provided so that their positions are freely adjustable in the direction of the axis of rotation of the arbor 10, with which the outside of flange of the material to be rolled is restrained and also the tip part of flange is rolled down and in which the width of flange forming grooves which is formed between the projecting part 12 and the sleeves 20, 20 is variable is used. While changing the width of the flange forming grooves for every each pass or for every several passes using this roughing mill, the inside of flange and web of the material to be rolled are rolled down with the projecting part 12 and also the outside of the material to be rolled is restrained with the sleeve 20, 20 and simultaneously the tip of flange is rolled down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of a shaped steel having a flange by hot rolling, in which a cast raw steel piece is rolled by a double type rough rolling machine having two rolling rolls at the top and bottom. TECHNICAL FIELD The present invention relates to a rough rolling mill and a rough rolling method for a shaped steel, which is effective in suppressing the variation in the cross-sectional shape of the material to be rolled in the rolling direction when performing rough rolling of a shaped steel having a flange.

In the present specification, "shaped steel having a flange" means I-shaped steel, grooved steel, equilateral angle steel, unequal edge angle steel, unequal side unequal thick angle angle steel, T-shaped steel and H. Shaped steel and the like are included, but from the viewpoint of convenience, the following description will be given by taking the H-shaped steel as an example.

[0003]

2. Description of the Related Art In the production of H-section steel by rolling, rough rolling (breakdown rolling) is carried out by a rough rolling machine on a crude steel piece heated to a predetermined temperature and extracted from a heating furnace, and then rough universal rolling. Coarse universal rolling and edger rolling (collectively referred to as "rough forming rolling") are performed by the mill and the edger rolling machine, respectively, and finally, the finish universal rolling machine finishes the finish universal rolling to a predetermined product size ("finish forming rolling"). Is performed to produce an H-section steel having predetermined dimensions.

In the rough rolling in the conventional manufacturing process of such H-section steel, after the flange bulging portion is formed in the material to be rolled in the edging rolling, the web is reduced by the flange shaping hole die to form the web. Although it is stretched, the flange portion is also stretched along with the stretching of the web, so that the cross-sectional area of the flange portion is excessively reduced due to the metal flow from the flange to the web. Therefore, when considering the final product dimensions, there arises a problem that the width of the flange part does not reach the predetermined width in the rolling direction, or the corner of the flange is not right angle, which is called the corner drop of the flange part. Problems such as these have also occurred.

In order to solve such a problem, Japanese Examined Patent Publication No. 2-14121 discloses a flange-shaped hole die having a horizontal distance (hereinafter referred to as "flange-formed hole width") which is an edge-rolled material. At least 10% more than the flange thickness after the end of, the flange forming hole full width is formed to be almost equal to the web height after the end of edging rolling, and the web pressing part has a central convex shape in the width direction. A method has been proposed in which a web portion of a material to be rolled is repeatedly pressed by a forming die formed by a curved surface to perform rolling while securing a metal flow to a flange portion.

On the other hand, in JP-A-57-171501, fluctuations in the filling rate of the flange occur because the flange side surface of the material to be rolled is not constrained during rolling. Therefore, a guide for guiding the material to be rolled is generated. Considering that the mechanism must be complicated, in order to solve the fluctuation of the flange filling rate, the flange of the rolled material is not deformed by the rolling roll,
A rough rolling method has been proposed in which only the web portion is rolled so that the ratio of the cross-sectional area of the unrolled portion to the total cross-sectional area of the rolled material is 0.6 or more. Here, the flange filling rate is calculated by the following formula.

[0007]

[Equation 1]

[0008]

However, in all of these conventional methods, fluctuations in the flange filling rate,
That is, there is a problem that the flange filling rate decreases as the rolling progresses.

Here, the fact that the flange filling rate is low means that there is a large portion that is not constrained by the flange shaping hole die during rolling, and in the end, there is a variation in the temperature of the material to be rolled in the longitudinal direction. The size and shape of the flange, such as flange thickness and flange width, will not be constant due to (burning condition).

Thus, the cross-sectional area of the flange shaping hole die,
When the cross-sectional area of the flange of the rolled material and the size of the flange are significantly different and the flange filling rate decreases, the cross-sectional area of the flange in the rolling direction of the rolled material fluctuates significantly, resulting in fluctuations in the flange thickness and flange width. It has the problem of becoming large.

Generally, after finishing the edging rolling,
When the reverse rolling of the web is performed a plurality of times with the same flange shaping hole die, as shown conceptually in FIG. 1 which is a graph showing the relationship between the web thickness and the flange filling rate,
The flange filling rate tends to decrease as the web becomes thinner due to reduction.

Therefore, the method proposed by Japanese Patent Publication No. 2-14121 or Japanese Patent Application Laid-Open No. 57-171501 does not reduce rolling even when the flange filling rate is high at the initial pass (at the start of rough rolling). Despite the fact that the flange filling rate tends to decrease as progressing and the end of rough rolling approaches, since a flange shaping hole die with a constant shape is used,
The flange filling rate decreases as the rolling progresses.
Therefore, in the design of the flange shaping hole die that already reduces the flange filling rate at the end of edging rolling,
The subsequent reduction of the web will further increase the variation of the cross-sectional area of the flange in the rolling direction, making it difficult to manufacture a shaped steel having a flange with excellent dimensional accuracy, and the size and shape of the final product It deteriorates the quality level.

An object of the present invention is to prevent the reduction of the flange filling rate due to the shrinkage of the flange due to the reduction of the web, to reduce the variation of the flange cross-sectional shape in the rolling direction of the material to be rolled, and to improve the dimensional accuracy. A rough rolling machine and a rough rolling method for a shaped steel capable of manufacturing a shaped steel having a flange.

[0014]

As described above, in the production of shaped steel by hot rolling, the crude steel billet extracted from the heating furnace is subjected to rough rolling including edging rolling and web rolling, and then rough universal rolling. Machine and edger rolling machine perform rough forming and rolling, and finally finish universal rolling machine performs finish forming and rolling to finally finish to desired product size.

The edging rolling in the rough rolling was performed by using a rough rolling machine having a flange shaping hole die having a predetermined constant cross-sectional shape, and then the web thickness was reduced. On the other hand, the present applicant uses an edger rolling machine having a variable flange forming hole width instead of the flange forming hole mold having such a constant cross-sectional shape, and the flange forming hole width is made to progress in web rolling. When rough rolling is performed by simultaneously reducing the inner surface of the flange and the web at the same time during edging rolling by appropriately changing it according to the above, the metal flow is stabilized and the unfilled or flange filled ratio is always reduced due to the thinning of the flange. The invention completed based on the finding that the fluctuation of the flange width in the rolling direction of the rolled material can be suppressed has been completed.
Proposed by No. 120675.

The rough rolling mill for shaped steel according to this proposal is roughly composed of an arbor, a convex portion at the center of the arbor, and two sleeves on both sides of the convex portion. Is a rough rolling mill which is arranged so that its position can be adjusted in the direction of the rotation axis of the arbor. However, as a result of further diligent studies, the present inventor has conceived a rough rolling mill capable of exhibiting the same effects as those described above, and completed the present invention.

The gist of the present invention is a rough rolling mill for shaped steel having a flange composed of a pair of upper and lower rolling rolls, and the rolling rolls are (i) arbor,
(ii) A convex portion having a cross-sectional shape, which is provided on the arbor, capable of pressing down the web of the rolled material and restraining the inner surface of the flange of the rolled material; and (iii) provided on one or both sides of the convex portion. And one or two sleeves having a sectional shape capable of restraining the outer surface of the flange of the rolled material and pressing down the flange tip of the rolled material, and the convex portion extends in the rotation axis direction of the arbor. Each of the divided parts is arranged so that its position can be adjusted in the direction of the rotation axis of the arbor. Of course, not only each of the divided convex portions but also one or two sleeves may be arranged so that the position thereof can be adjusted in the rotation axis direction of the arbor.

As described above, according to the present invention, the rough rolling in which the distance in the rotational axis direction of the arbor of the flange shaping hole formed between the convex portion and the sleeve, that is, the width of the flange shaping hole is adjustable. Machine is provided.

From another aspect, the present invention uses any one of the above-described rough rolling mills for shaped steel according to the present invention, and each pass or every few passes, the convex portion and, if necessary, the By moving the sleeve in the direction of the rotation axis of the arbor, the inner surface of the flange of the material to be rolled and the web are pressed down by the protrusions while the flange shaping hole width is adjusted, and the outer surface of the flange of the material to be rolled is constrained by the sleeve. In addition, it is a rough rolling method for shaped steel, characterized in that the tip of the flange is rolled down.

The "rough rolling" in the present invention refers to rough rolling (so-called breakdown rolling) in the steps of heating → rough rolling → rough forming rolling → finish forming rolling. The "flange having a flange" in the present invention includes I-shaped steel, channel steel, equilateral angle steel, unequal edge angle steel, unequal side unequal thickness angle steel, T-section steel and H-section steel. Included.

[0021]

The present invention will now be described in more detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, first, a rough rolling mill proposed by Japanese Patent Application No. 4-120675 will be briefly described.

FIG. 2 is an explanatory view of an example of the structure of a rolling roll used in a rough rolling mill for shaped steel having a flange composed of a pair of upper and lower rolling rolls, which is proposed by Japanese Patent Application No. 4-120675. In the figure, a convex portion 12 attached to the arbor 10 and having a sectional shape capable of restraining the inner surface of the flange of the material to be rolled and the arbor 10 on one side or both sides of the convex portion 12 (both sides in the illustrated example) are attached. A rolling roll 30 is shown which is composed of one or two sleeves 20 and 20 (two in the illustrated example) capable of restraining the outer surface of the flange of the material to be rolled and pressing down the tip of the flange.

In the rolling roll 30 shown in FIG. 2, the sleeves 20 and 20 which are movable and fixed in the direction of the rotation axis of the arbor 10 (the same direction as the one-dot chain line in the figure) and which restrain the flange outer surface of the material to be rolled. Are provided on the left and right sides of the convex portion 12. These sleeves 20, 20 are the general parts (convex parts) of the arbor 10.
It is a cylindrical member having an inner hole to be inserted into and attached to 12 parts other than the installation part). The outer diameter thereof may be larger than that of the convex portion 12 attached to the arbor 10, for example.

The means for moving / fixing the sleeves 20, 20 with respect to the rotation axis direction of the arbor 10, that is, the position adjusting means,
For example, it can be easily realized by known means using screws or hydraulic pressure. Explaining in detail the case of using a screw, a bolt hole reaching the surface of the arbor 10 is screwed on the circumference of the sleeve 20, and the sleeve 20 is screwed into the bolt hole so that the sleeve 20 can be inserted. Can be fixed to. Sleeve 20
In order to restrain the outer surface of the flange of the crude steel slab, which is the material to be rolled, and to roll down the tip of the flange during rolling, the cross section has a cross-sectional shape capable of performing these.

On the other hand, in order to restrain the inner surface of the flange of the rolled material, the arbor 10 is provided with the convex portion 12 having a sectional shape corresponding to the inner surface of the flange. In the illustrated example, the protrusion 12 is formed integrally with the main body of the arbor 10, but may be separable from the arbor 10. The projection 12 is configured to have a cross-sectional shape that matches a desired flange inner surface shape of the material to be rolled in order to reduce the inner surface of the flange and the web of the crude steel piece that is the material to be rolled during rolling.

Using the rough rolling machine in which the rolling roll 30 having the above-mentioned structure is incorporated as the upper and lower rolling rolls, the sleeves 20 and 20 are provided in the rotation axis direction of the arbor 10 for each rough rolling pass or every few passes. The flange inner surface and the web of the material to be rolled are pressed down by the protrusions 12 while adjusting the flange shaping hole width by moving the
20 and 20 to restrain the flange outer surface of the material to be rolled by pressing down the flange tip, in brief, by performing edging rolling and web rolling simultaneously in the state of restraining the flange bulging portion and the web, respectively, Since the flange filling rate for the flange shaping die can be increased, as a result, it is possible to manufacture a rough rolled product (meaning the material to be rolled at the end of rough rolling) with excellent dimensional accuracy and shape accuracy. Through the subsequent rough universal rolling step and finish universal rolling step, it is possible to manufacture shaped steel having excellent dimensional accuracy and shape accuracy.

FIG. 3 is an explanatory view of the situation during rough rolling.
As shown in the figure, the width of the flange forming hole of the flange forming hole die 32 is B on the base side of the web, A on the opposite side, and the average flange forming hole width K is K = (A + B) / 2. .
Similarly, the average flange thickness G of the rolled material 31 is G = (a
+ B) / 2.

Further, in FIG. 3, the web thickness is Tw.
In such a case, the conventional flange shaping hole die normally takes a rolling step for continuously thinning the web thickness Tw, except for the edging rolling which is performed to prevent the flange from biting in the middle, and the subsequent universal step. Roughly rolled products are sent to a universal mill group consisting of rolling mills and edger rolling mills.

FIG. 4 shows the flange forming hole die 32 shown in FIG.
The average flange forming hole width in the case of the conventional method in which the flange forming hole width is fixed when reverse rolling is performed in multiple passes so that the web thickness of the material to be rolled 31 is continuously reduced by 32. K or average flange thickness G
It is a graph which shows the relationship between and web thickness Tw. The subscripts 1 to 5 in the graph shown in the figure indicate the number of rolling passes of the reverse rolling, and this is the same in FIG. 6 described later.

As can be seen from the tendency shown in this graph, as the web is reduced (web thickness Tw is reduced),
Since the average flange thickness G decreases and the average flange shaping hole width K is constant, the flange shrinkage amount g given by (average flange shaping hole width K−average flange thickness G) is the web. It gradually expands with the reduction of. Therefore, the flange filling rate of the material to be rolled fluctuates in the rolling direction of the material to be rolled into the flange shaping die, and the dimensional accuracy of each of the flange thickness and the flange width of the shaped steel product is deteriorated. There was a flaw.

FIG. 5 is a schematic sectional view showing a state of rough rolling of a steel plate 33 during rough rolling by a rough rolling machine proposed by Japanese Patent Application No. 4-120675, in which arrows indicate sleeves 20, 20. The respective moving directions are shown.

In the figure, the steel strip 33 during rough rolling reduces not only the web thickness Tw but also the flange thickness and the flange width for each pass of the reverse rolling. Therefore, the sleeve 20, The width W of the flange forming hole is adjusted by adjusting the distance between 20 as appropriate.
Specifically, by adjusting the flange shaping hole die width W so as to decrease as the flange thickness decreases, it is possible to prevent a decrease in the flange filling rate and always maintain a constant flange filling rate.

As described above, in the rough rolling mill proposed by Japanese Patent Application No. 4-120675, the positions of the sleeves 20 and 20 can be freely adjusted with respect to the arbor (not shown).
Instead of making the sleeves 20, 20 positionally adjustable in the arbor rotation axis direction, the convex portion 12 is divided into a plurality of parts in the arbor rotation axis direction, and the respective divided parts are made positionally adjustable in the arbor rotation axis direction. Or sleeve 20, 20
Further, the flange forming hole width W is made variable by making the position of each of the convex portions 12 divided in the arbor rotation axis direction adjustable in the arbor rotation axis direction.

As described above, as can be seen from FIG. 2 or FIG. 5, the rolling rolls used in the rough rolling mill for shaped steel according to the present invention have the flange forming hole width W of the web rolling during the edging rolling. It is configured so that it can be adjusted appropriately for each pass.

FIG. 6 shows a case where reverse rolling is performed in a plurality of passes such that the web of the material to be rolled is continuously reduced by the flange shaping die, and the flange shaping die width is adjusted for each pass during the reverse rolling. 7 is a graph showing the relationship between the average flange shaping hole die width K or the average flange thickness G and the web thickness Tw.

As shown in FIG. 6, according to the present invention, the average flange shaping hole width K is reduced in accordance with the reduction of the average flange thickness G with the reduction of the web (reduction of the web thickness Tw). As a result, the flange shrinkage amount g can be made constant at each rolling pass.

FIG. 7 is a conventional rolling roll having a fixed flange shaping hole width corresponding to FIGS. 4 and 6, respectively.
6 is a graph showing the relationship between the flange filling rate and the web thickness associated with the web reduction when the rolling rolls used in the present invention each having a variable flange shaping hole width are used. In order to clarify the effect of the present invention, this graph is simply a rewriting of the results shown in the graphs of FIG. 4 and FIG. 6 by using the flange filling rate. Each example is represented by a dotted line.

From the graph shown in FIG. 7, according to the present invention,
It can be seen that the flange filling rate can be made constant at each stage of the edging rolling in which the web thickness gradually decreases. In other words, according to the present invention, even if the final free web thickness (meaning the web thickness at the end of rough rolling) of the rough rolling of the shaped steel is changed, the flange shaping hole width is appropriately changed accordingly. By adjusting it, it is possible to always send the rough rolled product with excellent flange filling rate to the subsequent rough universal rolling process and edger rolling process, and the variation of the flange width regardless of the final web thickness of the rough rolling. It is possible to supply a material to be rolled with a small amount.

The rolling roll having the variable width of the flange shaping hole referred to in the above description has, as an example, the sleeves 20 and 20 arranged with respect to the arbor 10 as shown in FIG. It is a rolling roll, and for example, it may have the same structure as a rolling roll having a variable hole width of an edger rolling mill as proposed by Japanese Patent Application No. 2-298050.

Further, if the rolling rolls used in the present invention are collectively applied to rough rolling rolls having a plurality of flange shaping holes and sequentially rolled by reverse rolling, two or more rolling rolls can be obtained. It is possible to reduce the number of various flange shaping hole molds that need to be integrated into one rolling roll, and to reduce the size, and by combining two or more rolling rolls into one rolling roll. It is also possible to reduce the number of rolling rolls held.

According to the present invention, the convex portion 12 is separably installed on the arbor 10, and the width of the convex portion 12 in the rotation axis direction can be changed appropriately as described above. That is, the convex portion 12 is configured to have a variable width and the sleeve 20 is fixed to the arbor 10. In this case, the protrusion 12 and the arbor 10 may be fixed by screws or hydraulic pressure as in the case of the sleeve described above. Hereinafter, the rough rolling mill according to the present invention using such a rolling roll will be described in detail.

FIG. 8 is an explanatory view of an example of the structure of the rolling roll 30 used in the rough rolling mill for shaped steel having a flange composed of a pair of upper and lower rolling rolls according to the present invention. As shown in FIG. A convex portion 12 having a sectional shape attached to the arbor 10, which can restrain the inner surface of the flange of the rolled material,
One or two attached to the arbor 10 on one side or both sides (both sides in the illustrated example) of the convex portion 12 capable of restraining the outer surface of the flange of the material to be rolled and pressing down the flange tip
A rolling roll 30 composed of two sleeves 20 and 20 (two in the illustrated example) is shown. In this example, the convex portion 12 is divided into two in the direction of the rotation axis of the arbor 10 (in the direction of the alternate long and short dash line). Each of the two divided components 12a and 12b is installed so that the position thereof can be adjusted in the direction of the rotation axis of the arbor 10, and the width of the convex portion 12 can be changed. The sleeves 20 and 20 are the arbor 10 in the example shown in FIG.
However, the position may be adjusted with respect to the rotation axis direction of the arbor 10 as described above.

As described above, in the rough rolling mill according to the present invention, (i) a rolling roll (rolling roll in FIG. 8) in which the convex portion can be divided / adjusted and the sleeve is fixed, and (ii) the convex portion can be divided / positioned. Using a rolling roll (not shown) that is adjustable and the sleeve position is adjustable,
Or by adjusting the flange forming hole die width by moving the convex portion in the direction of the rotation axis of the arbor, and simultaneously performing the reduction of the flange and the web, specifically, the convex portion by the inner surface of the flange of the rolled material and The web can be rolled down, the outer surface of the flange of the rolled material can be restrained by the sleeve, and the tip of the flange can be rolled down.

When the rolling roll shown in FIG. 8 is used, the degree of shrinkage of the flange is further alleviated as compared with the case where the rolling roll shown in FIG. It is more preferable that the flange filling rate for each is further increased as compared with the case where the rolling roll shown in FIG. 2 is used, and variations in the flange width and the flange thickness in the rolling direction can be significantly reduced. Hereinafter, the reason for this will be described in detail.

FIG. 9 is an explanatory view showing, in an enlarged manner, a portion surrounded by a broken line in the rolling roll 30 used in the present invention shown in FIG. 8 at the time of rolling. Reference numeral 12a is a divided convex at the end of rough rolling. The position of the portion, the reference numeral 12a 'shows the position of the divided convex portion at the start of rough rolling, respectively, the reference numeral 14 surrounded by a solid line, the shape of the material to be rolled at the end of rough rolling, by a dashed line. The enclosed reference numeral 14 'indicates the shape of the rolled material at the start of rough rolling.

When the rolling roll 30 shown in the same figure is used, assuming that the flange shaping hole die width at the end of rough rolling is W _f , the flange shaping hole at the initial pass stage of the flange shaping rolling after the edging rolling is finished. Set the die width to W _s , which is more than 1.1 times the flange shaping hole die width W _f at the end of rough rolling,
12a 'to 12
By moving to a, the metal flow from the flange to the web is significantly suppressed, and the fluctuation of the flange shaping hole width in the rolling direction is suppressed while preventing the reduction of the flange filling rate due to the thinning of the flange of the rolled material. To be done.

In other words, the thinning of the flange, which is caused by continuously rolling the web portion in the rolling direction in the rough rolling of shaped steel, is mainly due to the nonuniform rolling ratio distribution in the width direction of the material to be rolled. Conceivable.

Therefore, in the rough rolling mill according to the present invention equipped with the rolling roll having the cross-sectional shape shown in FIG. 8, each of the divided convex portions is positioned on the center side (the position indicated by the alternate long and short dash line in FIG. 9). ) Since rough rolling can be started, variations in the reduction ratio distribution in the width direction of the material to be rolled in the initial pass of rough rolling are alleviated, and metal flow in the flange web direction is reduced, which results in thinning. The degree is eased.

Further, at the stage of the initial pass of the flange shaping rolling, the flange shaping die width is set to W _S which is more than 1.1 times the flange shaping die width W _f at the end of the rough rolling.
By moving the divided convex parts so as to contact the material to be rolled against the shrinkage due to the subsequent web reduction, the flange filling rate for each pass is higher than before, and the flange width in the rolling direction is increased. And the variation in flange thickness is greatly reduced.

For convenience of explanation, the same drawing as FIG. 9 is shown again as FIG. The straight lines l and m in FIG. 10 are determined as straight lines which pass through the flange tip end of the sleeve 20 and contact the convex portion 12, respectively, and the angles θ ₁ and θ with respect to the horizontal direction of the straight lines l and m, respectively.
₂ is called the flange inner surface angle, which is the angle formed by the inner surface of the flange of the rolled material with the web at the end of rough rolling. Therefore, when the rolling roll shown in FIG. 9 is used, the metal flow of the material to be rolled at the time of rolling is adjusted by appropriately adjusting the shape of the tips of the divided convex portions and adjusting the flange inner surface angle. Furthermore, it becomes possible to improve the flange filling rate. Further, the present invention will be described in detail with reference to examples, but this is an example of the present invention and the present invention is not limited thereto.

[0051]

Example 1 In this example, as a comparative example, H-section steel was rolled by the steps of heating furnace → rough rolling (rolling pass number: 5) → rough universal rolling + edging rolling → finish universal rolling.

The rough rolling machine used for the rough rolling as a comparative example is as follows.
The rough rolling mill uses rolling rolls having the cross-sectional structure shown in FIG. 2 as upper and lower rolls, and has the same configuration as that of a known rough rolling mill except that the flange shaping hole width is variable.

The results are shown in Table 1 and the graph of FIG. Incidentally, the conventional example means a rolling method using a conventional rough rolling machine in which the flange shaping hole die width is constant.
In the graph shown in 11, the mark □ is an example of the present invention, and ○
The mark is a comparative example, and the mark is a conventional example.

As is clear from the graph of FIG. 11, according to the present invention, the flange filling rate can be constantly kept high at about 96% in the entire region from the start to the end of the edging rolling. Further, it can be seen from Table 1 that the dimensional accuracy of the flange width of the final product was significantly improved by the present invention.

[0055]

[Table 1]

[0056]

Example 2 A rough rolling machine using rolling rolls having the cross-sectional structure shown in FIG.
The H-section steel was subjected to rough rolling, and the flange filling rate at the time of this rough rolling was calculated using the above formula. Also, as a conventional example,
Similarly, the flange filling rate at the time of rough rolling was measured by using a conventional rough rolling machine having a constant flange shaping die width.

In the rough rolling mill using the rolling roll 30 having the sectional structure shown in FIG. 8 according to the present invention as the upper and lower rolls, the shapes of the tips of the divided convex portions 12a and 12b of the rolling roll 30 are appropriately adjusted. By doing so, the flange inner surface angle was increased by 2% as compared with the conventional rough rolling mill. As a result, according to the present invention, as shown in FIG. 11, it was possible to greatly improve the flange filling rate as compared with the conventional case.

[0058]

As described in detail above, according to the present invention,
It is possible to maintain the flange filling rate at the time of rough rolling at a high level without depending on the reduction of the flange thickness due to the reduction of the web thickness. Therefore, the dimensional accuracy of the flange width of the final product can be significantly improved, and it is possible to manufacture a shaped steel having a flange having very high dimensional accuracy with little dimensional variation in the rolling direction.

[Brief description of drawings]

FIG. 1 is a graph conceptually showing a relationship between a web thickness and a flange filling rate.

FIG. 2 is an explanatory view of an example of the structure of a rolling roll used in a rough rolling mill for shaped steel having a flange composed of a pair of upper and lower rolling rolls, which is proposed by Japanese Patent Application No. 4-120675.

FIG. 3 is an explanatory diagram of a situation during rough rolling.

FIG. 4 is a view showing a case where the flange shaping die width is fixed in the case where the multi-pass reverse rolling is performed so that the web thickness of the material to be rolled 31 is continuously reduced by the flange shaping die 32, 32 shown in FIG. 7 is a graph showing the relationship between the average flange shaping hole width K or the average flange thickness G and the web thickness Tw in the case of the conventional method.

FIG. 5 is a schematic cross-sectional view showing how a steel strip 33 during rough rolling is rolled by a rough rolling mill proposed by Japanese Patent Application No. 4-120675.

[FIG. 6] In the edging rolling, when the reverse rolling of multiple passes is performed so that the web of the material to be rolled is continuously reduced by the flange shaping die, the width of the flange shaping die is adjusted for each pass during the reverse rolling. Average flange forming hole width K or average flange thickness G
It is a graph which shows the relationship between and web thickness Tw.

FIG. 7 is a web obtained by using a conventional rolling roll having a fixed flange shaping die width corresponding to FIGS. 4 and 6, or a rolling roll used in the present invention having a variable flange shaping die width. It is a graph which shows the relationship between a flange filling rate and web thickness accompanying rolling.

FIG. 8 is an explanatory view of another example of the structure of a rolling roll 30 used in a rough rolling mill for shaped steel having a flange composed of a pair of upper and lower rolling rolls according to the present invention.

FIG. 9 is an explanatory view showing, in an enlarged manner, a portion surrounded by a broken line in the rolling roll 30 used in the present invention shown in FIG. 8 during rolling.

FIG. 10 is an explanatory view showing an enlarged portion surrounded by a broken line in the rolling roll 30 used in the present invention shown in FIG. 8 during rolling.

FIG. 11 is a graph showing the results of Example 1.

[Explanation of symbols]

 10: Arbor 12: Convex portion 12a, 12a ', 12b: Divided convex component member 14, 14': Rolled material 20: Sleeve 30: Rolling roll 31: Rolled material 32: Flange modeling die 33: Rough rolling medium billet

Claims (3)

[Claims] 1. A rough rolling mill for shaped steel having a flange composed of a pair of upper and lower rolling rolls, wherein the rolling rolls include (i) an arbor and (ii) a arbor. A convex portion having a cross-sectional shape capable of restraining the inner surface of the flange of the rolled material while pressing the web of the material, and (i
ii) One or two cross-sectional shapes provided on the arbor on one side or both sides of the convex portion, capable of restraining the flange outer surface of the rolled material and pressing down the flange tip of the rolled material. A rough rolling of shaped steel, characterized in that it is constituted by a sleeve, and the convex portion is divided in a rotational axis direction of the arbor and each of the divided portions is arranged to be positionally adjustable in the rotational axis direction. Machine. 2. The rough rolling mill for shaped steel according to claim 1, wherein the one or two sleeves are arranged so as to be positionally adjustable in the rotation axis direction. 3. The rough rolling mill according to claim 1 or 2, wherein the sleeve or / and the convex portion are moved in the rotational axis direction of the arbor for each pass or every few passes. While adjusting the distance in the rotation axis direction, while pressing down the flange inner surface and the web of the rolled material by the convex portion, while restraining the flange outer surface of the rolled material by the sleeve and pressing down the flange tip Method for roughly rolling shaped steel having a flange.