JP2013043186A - Method of manufacturing h-section steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing H-section steel with which high quality H-section steel can be manufactured from an H-section steel raw material having a flat cross section.SOLUTION: When a web rolling reduction amount when a web part of the H-section steel raw material formed into a dog bone shape is rolled and reduced by a web rolling reduction groove 11 is X and the width of flange parts formed on both sides of the web part is H, a width E between an inside face 11a of the web rolling reduction groove 11 and a bite-out suppressing part 13 formed between peripheral face parts of grooved rolls 6, 7 is set to E=0.10X/2 to 0.20X/2, a height h of the bite-out suppressing part 13 is set to h≤0.35H, and the H-section steel raw material is rough rolled.

Description

  The present invention relates to a method for manufacturing H-section steel by hot rolling, and particularly to a method for manufacturing H-section steel from an H-section steel material having a flat cross section.

  In recent years, H-section steels are often manufactured from H-section steel materials (for example, slabs) having a flat cross section from the viewpoints of energy saving and yield improvement. When manufacturing H-shaped steel from such H-shaped steel material by hot rolling, V-shaped splits are formed on both end faces of the H-shaped steel material as a rough rolling machine for rough shaping rolling of the H-shaped steel material. A split forming hole mold, a split depth increasing hole mold for increasing the split depth formed by the split forming hole mold, and an H-shaped steel material that has passed through the split depth increasing hole mold. Upper hole type rolls are a hole type for forming a dock bone formed into a dock bone shape, and a hole type for reducing the web for reducing the web part of the H-shaped steel material formed into a dock bone shape by the hole type for forming a dock bone. And the lower hole roll are used (see, for example, Patent Documents 1 and 2).

  However, when the H-shaped steel material is roughly modeled and rolled using such a rough rolling machine, the H-shaped steel material is rolled when the web portion of the H-shaped steel material shaped into a dockbone shape is reduced by a web-reducing hole mold. There is a case in which a biting phenomenon occurs in which the web portion bites between the upper hole-type roll and the lower hole-type roll on the outer surface side of the flange portion. And when such a biting phenomenon occurs, the web part bitten between the upper hole type roll and the lower hole type roll on the outer surface side of the flange part becomes an intermediate rolling process or a finish rolling process of the H-section steel material. By being crushed, there is a problem that a folding bite 17 or the like as shown in FIG. 9 is generated on the outer surface of the flange of the H-section steel 16 and the quality of the H-section steel 16 is deteriorated.

  As a method for suppressing the biting phenomenon described above, for example, when the web portion of the H-shaped steel material is rolled down by the web rolling hole mold, a concave portion is formed in the center portion of the outer surface of the flange portion formed on both sides of the web portion. A method of forming it has been proposed (see, for example, Patent Document 3).

Japanese Patent No. 2727943 Japanese Patent No. 3456438 JP 2011-16144 A

However, in the above method, when the concave portion formed on the outer surface of the flange portion is small, it is bitten when the rough shaped steel slab for H-section steel having a thin web portion is rough-rolled by a roughing mill. Since the phenomenon cannot be completely prevented, it is necessary to perform uniform rolling for about 1 to 2 passes, and there is a problem in that the rolling efficiency is lowered.
This invention is made in view of the problem mentioned above, and provides the manufacturing method of H-section steel which can manufacture high quality H-section steel from the H-section steel raw material whose cross section is flat shape. It is the purpose.

  In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that an H-section steel material having a flat cross section is roughly modeled and rolled from a roughing mill, and then the H-section steel material is intermediate-rolled by an intermediate rolling mill. A method for producing an H-section steel produced by finishing rolling with a finish rolling mill, wherein the rough rolling mill has a V-shaped split mold for forming V-shaped splits on both end faces of the H-section steel material, A split depth increasing hole mold for increasing the split depth formed by the split forming hole mold, and a dock for shaping the H-shaped steel material that has passed through the split depth increasing hole mold into a dock bone shape Between the upper and lower pair of perforated rolls, there is a perforated bone mold and a web-reducing hole mold that compresses the web portion of the H-shaped steel material shaped into a dockbone shape by the dock-bone shaped hole mold. The inner surface of the hole for web reduction and the hole A web portion having a biting restraint portion between the web portion and the web portion when the web portion is crushed by the web deflation hole mold, X is a web reduction amount, and flange portions are formed on both sides of the web portion. The width E of the biting suppression portion along the width direction of the web rolling hole mold is set to E = 0.10X / 2 to 0.20X / 2, and The H-section steel material is roughly shaped and rolled by setting the height of the biting suppression portion along the height direction of the hole mold to h ≦ 0.35H.

According to a second aspect of the present invention, the H-shaped steel material is roughly shaped and rolled using the biting suppression portion having a curved surface that is curved in an arc shape with respect to the inner surface of the web rolling hole mold. It is characterized by.
The invention of claim 3 is characterized in that the H-shaped steel material is roughly shaped and rolled by setting the curvature radius of the curved surface to 200 mm to 400 mm.

According to the invention of claim 1, it is possible to suppress the occurrence of biting phenomenon when the web portion of the H-shaped steel material shaped into a dock bone shape is squeezed by the web squeezing hole mold. Thus, biting flaws and the like are less likely to occur on the outer surface of the flange of the H-shaped steel, so that a high-quality H-shaped steel can be manufactured from an H-shaped steel material having a flat cross section.
According to the second and third aspects of the invention, since a linear corner portion is less likely to be generated at the boundary portion between the inner surface of the web rolling hole mold and the biting suppression portion, the streaks are formed on the outer surface of the flange of the H-shaped steel. It is possible to prevent the occurrence of wrinkles.

It is a figure which shows an example of the rolling equipment used for one Embodiment of this invention. It is a figure which shows the hole type | mold formed between the upper side hole type roll and lower side hole type roll of the rough rolling mill shown by FIG. It is a figure which shows the cross-sectional shape of the H-section steel raw material which passed the hole mold for split formation shown by FIG. It is a figure which shows the cross-sectional shape of the H-section steel raw material which passed the hole type for split depth increasing shown by FIG. It is a figure which shows the cross-sectional shape of the H-section steel raw material shape | molded by the dockbone shape by the dockbone shaping | molding hole type | mold shown by FIG. It is a figure which shows the cross-sectional shape of the H-section steel raw material by which the web part was reduced by the web mold | type for web reduction shown by FIG. It is a figure which shows the biting suppression part formed between the inner surface of the hole type | mold for web reduction shown by FIG. 2, and the surrounding surface part of a hole type roll. It is a figure which expands and shows the biting suppression part shown by FIG. It is a figure which shows the fold-shaped wrinkles which generate | occur | produce on the flange outer surface of H-section steel.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
The manufacturing method of the H-section steel according to one embodiment of the present invention is heat-treated in the rolling equipment shown in FIG. 1, that is, the heating furnace 2 that heats the H-section steel material 1 having a flat cross section, and the heating furnace 2. A rough rolling machine 3 for roughly shaping and rolling the H-shaped steel material 1, an intermediate rolling machine 4 for performing intermediate rolling on the H-shaped steel material 1 after rough shaping, and a finishing mill for finishing rolling the H-shaped steel material 1 The rough rolling mill 3 is divided between an upper perforated roll 6 and a lower perforated roll 7 as shown in FIG. It has a forming hole mold 8, a split depth increasing hole mold 9, a dock bone forming hole mold 10, and a web reducing hole mold 11.

The split forming hole mold 8 is a hole mold that forms a V-shaped split on both side end surfaces of the H-shaped steel material 1, and the H-shaped steel material 1 that has passed through the split forming hole mold 8 is shown in FIG. Such a cross-sectional shape, that is, a cross-sectional shape in which V-shaped splits 12 are formed on both end faces of the H-shaped steel material 1 is obtained.
The split depth increasing hole mold 9 is a hole mold formed on both end faces of the H-section steel material 1 to increase the split depth, and the H-section steel material that has passed through the split depth increasing hole mold 9 is provided. 1 has a cross-sectional shape as shown in FIG.

The dock bone modeling hole mold 10 is a hole mold for modeling the H-shaped steel material 1 that has passed through the split depth increasing hole mold 9 into a dock bone shape. The shaped H-shaped steel material 1 has a cross-sectional shape as shown in FIG. 5, that is, a cross-sectional shape in which flange portions 1b are formed on both sides of the web portion 1a.
The web reducing hole mold 11 is a hole mold for rolling down the web portion 1a of the H-shaped steel material 1 shaped in a dock bone shape, and the web section 1a is rolled down by the web rolling hole mold 11. The material 1 has a cross-sectional shape as shown in FIG.

  The rough rolling mill 3 also has a biting suppression portion 13 (see FIG. 7) between the inner side surface 11a of the web pressing hole mold 11 and the peripheral surface portions of the hole rolls 6 and 7. The biting suppression portion 13 has a convex curved surface shape with the corners of the inner surface 11a of the web-rolling hole mold 11 and the peripheral surfaces 6a and 7a of the hole rolls 6 and 7 extending in the width direction and h in the roll radial direction. When the web part 1a of the H-shaped steel material 1 shaped into a dock bone shape is squeezed by the web-squeezing hole mold 11, the web part 1a becomes the peripheral surface part 6a and the lower hole of the upper hole-type roll 6. It suppresses biting between the peripheral surface portion 7 a of the mold roll 7. When the web portion 1a of the H-shaped steel material 1 formed in the dockbone shape is squeezed by the web squeezing hole mold 11, the web squeezing amount (web thickness before web squeezing-web thickness after web squeezing) is X. Then, the width E (see FIG. 8) of the biting suppression portion 13 along the width direction of the web-rolling hole mold 11 (the axial direction of the hole rolls 6 and 7) is E = 0.10X / 2 to 0.20X. / 2 is set.

  The reason why the width E of the biting suppression portion 13 is set as described above with respect to the web reduction amount X is that the width spread amount of the H-section steel material 1 (hole type) when the web is reduced by the hole rolls 6 and 7. This is based on the idea of changing the width E of the biting suppression portion 13 in accordance with the amount of extension of the H-shaped steel material along the roll 6 and 7 axial directions. That is, the larger the amount of spread of the web when the web is reduced, the larger the amount of biting between the peripheral surface portion 6a and the peripheral surface portion 7a. Therefore, the width E of the biting suppression portion 13 for preventing biting is the web. It is necessary to increase as the amount of breadth at the time of rolling down increases. And the amount of breadth at the time of web reduction becomes so large that the amount of web reduction is large. Therefore, the width E of the biting suppression unit 13 is set with respect to the web reduction amount X. If the width E of the biting suppression portion 13 is less than 0.10X / 2, the biting of the material between the peripheral surface portion 6a and the peripheral surface portion 7a during web reduction cannot be suppressed. On the other hand, when the width E of the biting suppression portion 13 exceeds 0.20X / 2, biting between the peripheral surface portion 6a and the peripheral surface portion 7a can be suppressed, but the H The cross-sectional shape of the outer surface of the flange of the shaped steel material 1 becomes a large convex shape, and the subsequent intermediate rolling mill 4, specifically, the universal rolling mill cannot be correctly bitten, resulting in a defective shape. Accordingly, the width E of the biting suppression portion 13 is set to a range of E = 0.10X / 2 to 0.20X / 2 with respect to the web reduction amount X.

  Further, if the width of the flange portion 1b of the H-shaped steel material 1 shaped in a dock bone shape is H, the biting along the height direction of the web-reducing hole mold 11 (the radial direction of the hole rolls 6 and 7). The height h (see FIG. 8) of the suppression unit 13 is set to h ≦ 0.35H. This is because when the height h exceeds 0.35H, the cross-sectional shape of the flange outer surface of the H-section steel material 1 after being reduced by the perforated rolls 6 and 7 becomes a large convex shape. This is because the universal rolling mill cannot be correctly bitten. If the height h is too small, the biting suppression effect is reduced, and therefore it is preferably 0.15H or more.

  The biting suppression unit 13 also has a convex curved surface 14 (see FIG. 8) that is curved in an arc shape with respect to the inner surface 11a of the web rolling hole mold 11, and the curvature radius of the curved surface 14 is as follows. It is 200 mm to 400 mm. Further, the biting suppression portion 13 has a connecting surface 15 (see FIG. 7) that connects the curved surface 14 and the peripheral surface portions of the hole-type rolls 6 and 7, and the connecting surface 15 has a curvature smaller than the curvature radius of the curved surface 14. It is formed in a convex arc shape with a radius.

  When roughly shaping the H-section steel material 1 using such a rough rolling mill 3, the H-section steel material 1 is inserted into the split-forming hole mold 8, and V-shaped on both side end faces of the H-section steel material 1. A split 12 is formed. Next, after inserting the H-shaped steel material 1 into the hole mold 9 for increasing the split depth to increase the depth of the split 12, the H-shaped steel material 1 is formed into a dock bone shape by the dock bone forming hole mold 10. To do. Then, the H-section steel material 1 shaped in a dock bone shape is inserted into the web-reducing hole mold 11 to reduce the web portion 1 a of the H-section steel material 1.

  At this time, since the biting suppression portion 13 is formed between the inner side surface 11a of the web pressing hole mold 11 and the peripheral surface portions of the hole rolls 6 and 7, the web portion 1a of the H-shaped steel material 1 is formed. The biting suppression part 13 suppresses biting between the peripheral surface part 6 a of the upper hole-type roll 6 and the peripheral surface part 7 a of the lower hole-type roll 7.

  The inventors set the width E of the biting suppression portion 13 to E = 0.08X / 2, E = 0.10X / 2, E = 0.20X / 2, E = 0.25X / 2. The occurrence of the biting phenomenon was investigated by setting the height h of the biting suppression unit 13 to h = 0.20H, h = 0.30H, h = 0.35H, h = 0.40H. The survey results are shown in Table 1.

As shown in Table 1, in Comparative Example 1, since the width E of the biting suppression portion is too small as 0.08X / 2, the web portion 1a of the H-section steel material 1 shaped in a dock bone shape is reduced in the web. A biting phenomenon occurred when the punch 11 was squeezed down. And in the comparative example 1, the bite 17 (refer FIG. 9) arose on the flange outer surface of the H-shaped steel after finish rolling.
Further, in Comparative Example 2 and Comparative Example 3, the biting suppression phenomenon did not occur because the width E of the biting suppression portion was too large or the height h of the biting suppression portion was too large. When the web portion 1a of the shaped H-shaped steel material 1 is squeezed by the web die 11 for web reduction, the shape of the flange portion 1b becomes unsuitable. .

On the other hand, in Example 1, Example 2, Example 3 and Example 4, when the web part 1a of the H-section steel material 1 shaped into a dock bone shape is reduced by the web-type reduction hole mold 11, it bites. No sticking out phenomenon or shape defect occurred.
Therefore, as described above, as a rough rolling machine for roughly shaping and rolling the H-shaped steel material 1 having a flat cross section, the split forming hole mold 8 for forming the V-shaped split 12 on both side end surfaces of the H-shaped steel material 1 is used. And a split depth increasing hole mold 9 for increasing the depth of the split 12 formed by the split forming hole mold 8, and an H-shaped steel material 1 having passed through the split depth increasing hole mold 9 in a dock bone shape. A hole roll for forming a dock bone forming hole mold 10 to be formed into a shape and a web pressing hole mold 11 for reducing the web portion 1a of the H-shaped steel material 1 formed into a dock bone shape by the dock bone forming hole mold 10 6 and 7 and having a biting suppression portion 13 between the inner side surface 11a of the web pressing hole mold 11 and the peripheral surface portion of the hole rolls 6 and 7, and is formed into a dock bone shape. The web part 1a of the H-shaped steel material 1 Biting suppression portion along the width direction of the web pressing hole mold 11 where X is the amount of web reduction when being pressed by the hole mold 11 and H is the width of the flange section 1b formed on both sides of the web section 1a. 13 is set to E = 0.10X / 2 to 0.20X / 2, and the height h of the biting suppression portion 13 along the height direction of the web pressing hole mold 11 is set to h ≦ 0.35H. It is possible to suppress the occurrence of the biting phenomenon when the web portion 1a of the H-shaped steel material 1 shaped in a dock bone shape is squeezed by the web squeezing hole die 11. As a result, biting flaws and the like hardly occur on the outer surface of the flange of the H-shaped steel, so that a high-quality H-shaped steel can be manufactured from an H-shaped steel material having a flat cross section.

  In addition, as in the above-described embodiment of the present invention, the biting suppression portion 13 is an H-shaped member that has a curved surface 14 that is curved in an arc shape with respect to the inner surface 11a of the web pressing hole mold 11. Since the steel material 1 is roughly shaped and rolled, a linear corner portion is less likely to be generated at the boundary between the inner surface 11a of the web rolling die 11 and the biting suppression portion 13, so that the flange outer surface of the H-shaped steel It is possible to prevent the occurrence of streak-like wrinkles.

DESCRIPTION OF SYMBOLS 1 ... H-section steel material 1a ... Web part 1b ... Flange part 2 ... Heating furnace 3 ... Rough rolling mill 4 ... Intermediate rolling mill 5 ... Finishing rolling mill 6 ... Upper punch roll 7 ... Lower punch roll 8 ... Split formation Hole type 9 ... Hole type for increasing split depth 10 ... Hole type for forming dock bone 11 ... Hole type for web reduction 11a ... Inner side surface of hole type for web reduction 12 ... Split 13 ... Biting suppression part 14 ... Curved surface 15 ... Connecting surface 16 ... H-section steel 17 ... Biting rod

Claims (3)

An H-section steel produced by roughly shaping and rolling an H-section steel material having a flat cross section from a roughing mill, and then intermediate rolling the H-section steel material by an intermediate rolling mill and then finishing rolling by a finishing mill. A manufacturing method of
As the rough rolling mill, a split forming hole mold for forming a V-shaped split on both end faces of the H-shaped steel material, and a split depth increase for increasing the split depth formed by the split forming hole mold Hole shape, a hole shape for forming a dock bone that forms the H-shaped steel material that has passed through the hole shape for increasing the split depth into a dock bone shape, and a hole shape for forming the dock bone, Between the upper and lower pair of perforated rolls, there is a web downhole mold for lowering the web portion of the H-shaped steel material, and between the inner surface of the web downhole mold and the peripheral surface portion of the perforated roll. Use one that has a biting suppression part,
When the web part is reduced by the web reduction hole mold, the web reduction amount is X, and the width of the flange part formed on both sides of the web part is H. The width direction of the web reduction hole mold The width E of the biting suppression portion along the width is set to E = 0.10X / 2 to 0.20X / 2, and the height of the biting suppression portion along the height direction of the web pressing hole mold is set to A method for producing an H-section steel, characterized in that the H-section steel material is roughly shaped and rolled by setting h ≦ 0.35H.   The H-shaped steel material is roughly shaped and rolled using the biting suppression portion having a curved surface that is curved in an arc shape with respect to the inner surface of the web-rolling hole mold. The manufacturing method of the H-section steel as described in 2.   The method for producing an H-shaped steel according to claim 2, wherein the curvature radius of the curved surface is set to 200 mm to 400 mm, and the H-shaped steel material is roughly shaped and rolled.

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