JP2013094804A - Rough rolling machine for manufacturing h-section steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rough rolling machine for manufacturing an H-section steel, by which rough rolling can be performed stably for the H-section steel material which has been cast or rolled so as to have an H cross-section even when the amount of increase in the web height is large in manufacture of the H-section steel having a web height of from 400 mm to 1,000 mm.SOLUTION: In the rough rolling machine for manufacturing the H-section steel having a pair of upper and lower flange expanding protrusions for expanding the flange inner surface to the flange outer surface of the H-section steel material which has been cast or rolled so as to have an H cross-section in a central portion of a caliber formed between an upper caliber roll and a lower caliber roll, a corner part of a circumferential surface part 4a and right and left side surface parts 4b and 4c of the flange expanding protrusion is formed from two continuous arcs R1 and R2, and the radius of curvature of the second arc R2 contiguous with the right and left side surface parts 4b and 4c, from among the two arcs R1 and R2, is made greater than the radius of curvature of the first arc R1 contiguous with the circumferential surface part 4a.

Description

  The present invention relates to a roughing mill used when manufacturing H-section steel by hot rolling.

  As a method of manufacturing H-section steel by hot rolling, double rough rolling of rolling equipment shown in FIG. 8 is used for H-section steel materials such as slabs and blooms having a rectangular cross section or a beam blank cast into an H-shaped section. Formed and rolled into a cross-sectional shape according to the product dimensions by the machine BD, and then brought the web thickness and flange outer dimensions of the H-section steel material closer to the product dimensions in the intermediate rolling process using the rough universal rolling machine UR and the edger rolling machine E Thereafter, there is known a method in which a web of an H-shaped steel material is lightly reduced in a finishing rolling process by a finishing universal rolling mill UF and a flange is formed vertically to finish a product size.

When manufacturing H-section steel by such a method, since there are only a few types of beam blanks having different web heights and flange widths, the web height varies from 50 mm to 100 mm within a range of 400 mm to 1000 mm, for example. When manufacturing several types of H-section steel, it is necessary to enlarge the web height of a beam blank according to a product dimension.
In addition, when manufacturing H-section steel from slabs and blooms as well as beam blanks, multiple types can be used with one type of perforated roll if the web height of the slabs and blooms shaped and rolled into a H-shaped section can be increased with a roughing mill. This makes it possible to reduce the number of rolls held and to reduce the manufacturing cost.

  Therefore, as a technique for expanding the web height of an H-shaped steel material cast or rolled into an H-shaped cross section, Patent Document 1 discloses an upper perforated roll 1 of a rough rolling mill as shown in FIG. And a flange-opening convex part 4 that protrudes from the peripheral surface part of the hole-type rolls 1 and 2 is formed in the center part of the hole-type formed between the lower hole-type roll 2 and the lower-hole type roll 2 4 discloses a technique for expanding the web height H of the H-shaped steel material 5 by expanding the flange 5a of the H-shaped steel material 5 toward the flange outer surface side.

  Further, in Patent Document 2, as shown in FIG. 10, the expansion by the flange-expanding convex portion 4 is started from the flange inner surface of the H-shaped steel material 5, and the flange-expanding convex portion 4 is the H-shaped steel. When the distance D from the flange tip when contacting the flange inner surface of the material 5 to the peripheral surface portion 4a of the flange expanding convex portion 4 and the flange expanding convex portion 4 contact the web surface of the H-shaped steel material 5 A technique for increasing the web height of the H-shaped steel material by setting the distance C between the outer surface of the flange and the outer surface of the hole mold in an appropriate range is disclosed.

Japanese Patent Publication No. 55-30921 Japanese Patent No. 4167572

  However, in the technique disclosed in Patent Document 1, the corner portion 4d of the peripheral surface portion 4a and the left and right side surface portions 4b, 4c of the flange-extending convex portion 4 is formed from one arc, and the corner portion 4d is formed in an H shape. Since the web height is increased by first contacting the flange tip inner corner portion 5c of the steel material 5, if the curvature radius of the corner portion 4d is increased to increase the web height expansion amount, H When the web 5b of the shaped steel material 5 is lightly reduced by the peripheral surface portion 4a of the convex part 4 for expanding the flange, the radius of curvature of the arcuate curved portion 5d that connects the web 5b of the H-shaped steel material 5 and the inner surface of the flange increases. . For this reason, the amount of reduction at the time of rolling down the arcuate curved portion 5d at the horizontal roll corner of the rough universal rolling mill UR is increased, so that a flaw that deteriorates the product quality occurs in the H-shaped steel material, or the rough universal rolling mill There was a problem that the horizontal roll corner of the UR was worn or damaged. In Patent Document 1, after roughly rolling the H-shaped steel material 5 with a hole shape having a large curvature radius of the corner portion 4d, the H-shaped steel material 5 is formed with another hole shape having an appropriate curvature radius of the corner portion 4d. Although it is disclosed that it is shaped and then conveyed to the rough universal rolling mill UR, since the roll width of the rough rolling mill is limited, it is difficult to increase the number of perforations.

  On the other hand, in the technique disclosed in Patent Document 2, the corner portion 4d of the flange-extending convex portion 4 is first brought into contact with the flange inner surface of the H-shaped steel material 5 to increase the web height. However, there is a problem that it is difficult to increase the web height enlargement amount as compared with the technique disclosed in Patent Document 1. Further, in the technique disclosed in Patent Document 2, when the outer surface shape of the flange assumed when designing the hole mold is different from the shape in the actual rolling, the distance D is different from the design value. There is also a problem of uncertainty in the hole design stage, which may be out of range.

  The present invention has been made in view of the above-mentioned problems, and rough rolling of an H-shaped steel material cast or rolled into an H-shaped cross section when manufacturing an H-shaped steel having a web height of 400 mm to 1000 mm. An object of the present invention is to provide a rough rolling mill for producing H-section steel that can be stably performed even when the amount of web height expansion is large.

  In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that a pair of upper and lower flange-extending convex portions for expanding the flange inner surface of the H-shaped steel material cast or rolled into an H-shaped cross section toward the flange outer surface side is provided on the upper side. A rough rolling mill for manufacturing an H-section steel having a central portion of a hole mold formed between a hole roll and a lower hole roll, the peripheral surface portion and the left and right side surfaces of the flange-spreading convex portion The corner portion of the two arcs is formed from two continuous arcs, and the radius of curvature of the second arc connected to the left and right side portions of the two arcs is set to be larger than the radius of curvature of the first arc connected to the peripheral surface portion. It is characterized by.

According to a second aspect of the present invention, in the rough rolling mill for manufacturing the H-section steel according to the first aspect, the radius of curvature of the first arc is set to a radius of curvature of 30 mm to 80 mm.
A third aspect of the invention is the rough rolling mill for manufacturing the H-section steel according to the first or second aspect, wherein the radius of curvature of the second circular arc first comes into contact with the flange tip inner corner of the H-section steel material. It is characterized by a radius.
The invention of claim 4 is the rough rolling mill for H-section steel production according to any one of claims 1 to 3, wherein the radius of curvature of the second arc is a radius of curvature of 200 mm to 2000 mm. And

  According to the present invention, the radius of curvature of the curved portion connecting the flange inner surface of the H-shaped steel material and the web surface does not become too large as the web height increases. When the curved part of the H-section steel material is rolled down at the corner, the reduction amount becomes too large, causing defects in the H-section steel material that deteriorate the product quality, and wear or wear at the horizontal roll corner of the rough universal rolling mill. Since it is possible to suppress the occurrence of damage, rough rolling of an H-section steel material cast or rolled into an H-shaped cross section can be stably performed even when the amount of web height expansion is large. it can.

It is a figure which shows a part of hole-type roll of the rough rolling mill for H-section steel manufacture which concerns on one Embodiment of this invention. It is a figure which expands and shows the A section of FIG. It is a figure for demonstrating the upper limit of the curvature radius of the 2nd circular arc formed in the corner part of the convex part for flange expansion. It is a figure which shows the relationship between the distance between intersection points, and the curvature radius of a 2nd circular arc. It is a figure which shows the state which the 2nd circular arc formed in the corner part of the convex part for a flange expansion spread contacted the flange front-end | tip inside corner part of a H-section steel material. It is a figure which shows the state by which the flange of the H-shaped steel raw material was expanded to the flange outer surface side by the convex part for flange expansion. It is a figure for demonstrating the difference when the corner part of the convex part for flange expansion is formed from one circular arc, and when it forms from two circular arcs. It is a figure which shows an example of the rolling equipment used when manufacturing H-section steel. It is a figure for demonstrating the technique disclosed by patent document 1. FIG. It is a figure for demonstrating the technique disclosed by patent document 2. FIG.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the rough rolling mill for manufacturing an H-section steel according to an embodiment of the present invention is the center of a hole mold 3 formed between an upper hole mold roll 1 and a lower hole roll 2. It has a pair of upper and lower flange-extending convex portions 4 on the part.
The flange-protruding convex portion 4 is for expanding the flange 5a of the H-shaped steel material 5 shown in FIG. 9, that is, the H-shaped steel material 5 cast or rolled into the H-shaped cross section, toward the outer surface of the flange. The rolls 1 and 2 are formed over the entire circumference on the peripheral surface portions.

  Further, the flange-extending convex portion 4 has a peripheral surface portion 4a and left and right side surface portions 4b and 4c, and the corner portion 4d between the peripheral surface portion 4a and the left and right side surface portions 4b and 4c is as shown in FIG. , Formed from two continuous arcs R1, R2. Of these arcs R1 and R2, the first arc R1 connected to the peripheral surface portion 4a of the flange-spreading convex portion 4 is formed in the corner portion 4d of the flange-spreading convex portion 4 with a radius of curvature of 30 to 80 mm. .

  On the other hand, the second arc R2 connected to the left and right side surfaces 4b, 4c of the flange-spreading convex portion 4 has a radius of curvature larger than that of the first arc R1, preferably at the flange tip inner corner portion 5c of the H-shaped steel material 5. It is formed in the corner part 4d of the convex part 4 for flange expansion with the curvature radius which contacts, More preferably, the curvature radius of 200 mm or more and 2000 mm or less. Note that the left and right side surfaces 4b and 4c of the flange-extending convex portion 4 are inclined surfaces that are inclined with respect to the peripheral surface portion 4a at a spread angle of 70 °, for example.

Here, the reason why the lower limit of the radius of curvature of the second arc R2 is set to 200 mm is that the web height H of the H-section steel material 5 is stably increased when the radius of curvature of the second arc R2 is less than 200 mm. This is because it becomes difficult.
The reason why the upper limit of the radius of curvature of the second arc R2 is 2000 mm is as follows. That is, as shown in FIG. 3, the inclination angle of the left and right side surface parts 4b and 4c with respect to the peripheral surface part 4a of the flange-spreading convex part 4 is θ (°), and the left and right side surface parts 4b and 4c of the flange-spreading convex part 4 are Is the connection point between the second arc R2 and the second arc R2, the height from the line extending from the peripheral surface 4a of the flange-spreading convex portion 4 to the point T is h, and the peripheral surface portion 4a of the flange-spreading convex portion 4 is extended. C1 is an intersection point where the line extending from the right and left side surfaces 4b and 4c intersects, and C2 is an intersection point where the line extending from the second arc R2 intersects the line extending the peripheral surface portion 4a of the convex part 4 for expanding the flange. If the distance between the intersections C1 and C2 is d, the distance d between the intersections is determined by the inclination angle θ, the height h, and the radius of curvature of the second arc R2. When the inclination angle θ is θ = 70 ° and the height h is h = 180 mm, as shown in FIG. 4, when the radius of curvature of the second arc R2 exceeds 2000 mm, the inter-intersection distance d becomes 10 mm or less, As a result, the amount of enlargement w of the web height H also becomes smaller, so the upper limit of the radius of curvature of the second arc R2 is set to 2000 mm.

  When the upper hole roll 1 is lowered after inserting the H-shaped steel material 5 into the hole mold 3 of such a rough rolling mill for H-section steel production, as shown in FIG. The second arc R <b> 2 contacts the flange tip inner corner portion 5 c of the H-shaped steel material 5. When the upper perforated roll 1 is further lowered, as shown in FIG. 6, the flange 5 a of the H-shaped steel material 5 is expanded to the flange outer surface side by the flange-expanding convex part 4, thereby The web height H of the steel material 5 increases.

  At this time, the first arc R1 of the flange spreading convex part 4 abuts on the arcuate curved part 5d that connects the web 5b of the H-shaped steel material 5 and the inner surface of the flange, but the curvature radius of the first arc R1 is arcuate. Since the curvature radius is substantially the same as the curvature radius of the curved portion 5d (see FIG. 5), that is, a curvature radius of 30 to 80 mm, the curvature radius of the arc-shaped curved portion 5d increases as the web height H increases. Never too much.

  Therefore, when the curved portion 5d of the H-shaped steel material 5 is rolled down at the horizontal roll corner of the rough universal rolling mill, the H-shaped steel material 5 has wrinkles that reduce the product quality due to excessive reduction. Since it is possible to suppress the occurrence of wear and damage at the horizontal roll corner of the rough universal rolling mill, it is cast into an H-shaped cross section when manufacturing an H-shaped steel having a web height of 400 mm to 1000 mm. Alternatively, rough rolling of the rolled H-shaped steel material can be performed stably even when the amount of web height expansion is large.

  Further, the corner portion 4d is formed at one corner Rd of the H-shaped steel material 5 when the corner portion 4d of the convex portion 4 for expanding the flange is formed from one arc R1 and two arcs R1, R2. Comparing the angle α in contact with 5c, as shown in FIG. 7, the angle α is obtained by forming the corner portion 4d from two arcs R1 and R2 and calculating the radius of curvature of the arc R2 connected to the side portions 4a and 4c as the peripheral surface portion. It can be seen that the larger the radius of curvature of the arc R1 connected to 4a, the larger. When the angle α is increased, the rolling is stabilized, and the rolling stability can be ensured even when the web height is increased. Therefore, it is possible to manufacture an H-section steel having a web height of 400 mm to 1000 mm by increasing the web height of the H-section steel material in the rough rolling process.

  An H-shaped steel material having a web thickness of 80 mm, a flange width of 480 mm, and a web height of 800 mm was rolled with the hole mold 3 shown in FIG. 1 to increase the web height. At this time, the inclination angle of the left and right side surface parts 4b and 4c of the flange-extending convex part 4 is 70 °, the radius of curvature of the first arc R1 is 50 mm, the radius of curvature of the second arc R2 is 300 mm, and the height h shown in FIG. H = 120 mm, and the distance d between the intersections was d = 37.1 m.

When the flange of the H-shaped steel material is expanded to the outer surface side of the flange by the flange-expanding convex part 4, the web height expansion amount w becomes 100 mm, and the second arc R2 is the flange-end inner corner of the H-shaped steel material. The hole shape was designed to contact the part first, and the web height was increased.
When the web height was increased, rolling was performed with a roll gap that did not substantially reduce the web of the H-shaped steel material. When the web height was expanded by passing 10 H-shaped steel materials through the hole mold, stable rolling was performed on all the H-shaped steel materials, and the web height could be increased by 100 mm as planned. The height was 900 mm.

  Next, the H-shaped steel material having a web height of 900 mm is passed through another hole mold (not shown) formed between the upper hole roll 1 and the lower hole roll 2 in FIG. The web height was increased. FIG. 3 shows the inclination angle of the left and right side surfaces of the flange-spreading convex portion formed at the center of this hole mold as 70 °, the radius of curvature of the second arc is 300 mm, and the radius of curvature of the first arc is 50 mm. The height h to the contact T was 120 mm, and the distance d between the intersections was 37.1 mm. The dimension in the width direction of the hole mold was designed so that the web height enlargement amount was 100 mm, and the roll height was rolled with the roll interval set to 80 mm. As a result, the web height was 998 mm, and it was possible to roll to a substantially target web height. Moreover, when 10 H-section steel materials were rolled, all the H-section steel materials could be stably rolled, and the H-section steel materials were not twisted or bent.

  As a comparative example, ten other H-shaped steel materials having the same dimensions were prepared, and the connecting portion of the flange-extending convex portion was formed of one arc (curvature radius: 50 mm), and the web height was expanded and rolled. . Rolling was performed with the roll interval set to 80 mm as in the example of the present invention, but twisting occurred in the H-shaped steel material in 4 of the 10 H-shaped steel materials, so the rolling was stopped halfway. . In addition, although the remaining three could be rolled with a relatively small twist, the tip of the inner surface of the flange was crushed or the shapes of the left and right flanges were different. became.

  In the above-described embodiment of the present invention, an example in which one hole mold is formed between the upper hole roll and the lower hole roll is exemplified. It may be formed between the side hole type rolls, and a flange-extending convex part may be formed at the center of each hole type.

BD ... Rough rolling mill UR ... Rough universal rolling mill E ... Edger rolling mill UF ... Finishing universal rolling mill 1 ... Upper hole roll 2 ... Lower hole roll 3 ... Hole mold 4 ... Flanged expansion 4a ... Flange Peripheral surface parts 4b, 4c of the convex part for expanding the flange 4d ... Right and left side parts of the convex part for expanding the flange 4d ... Joint part of the convex part for expanding the flange 5 ... H-shaped steel material 5a ... Flange 5b of the H-shaped steel material 5 ... H Shaped steel web 5c… H-shaped steel material flange tip inner corner R1… first arc R2… second arc

Claims (4)

A pair of upper and lower flange-spreading projections are formed between the upper hole roll and the lower hole roll so as to push the flange inner surface of the H-shaped steel material cast or rolled into an H-shaped cross section toward the outer surface of the flange. A rough rolling mill for producing H-section steel at the center of the hole type,
The peripheral surface portion of the flange-spreading convex portion and the left and right side surface portions are formed from two continuous arcs, and the curvature radius of the second arc connected to the left and right side surface portions of the two arcs is defined as the peripheral surface portion. A rough rolling mill for producing H-section steel, characterized in that the radius of curvature is larger than the radius of curvature of the first arc connected to the first arc.   2. The rough rolling mill for manufacturing H-section steel according to claim 1, wherein a curvature radius of the first arc is set to a curvature radius of 30 mm to 80 mm.   3. The rough rolling mill for manufacturing H-section steel according to claim 1, wherein the curvature radius of the second arc is a curvature radius that first comes into contact with a flange tip inner corner portion of the H-section steel material.   The rough rolling mill for manufacturing H-section steel according to any one of claims 1 to 3, wherein the radius of curvature of the second arc is 200 mm or more and 2000 mm or less.

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