JPS6174701A - Manufacture of h-beam - Google Patents

Abstract

PURPOSE:To obtain a product excellent in shape dimensions by rolling a rough- shaped billet, having a recessing part of longitudinal direction at the outer-face center of its flange, by vertical rolls, having each a projecting part at the center of its outer periphery, so as to provide and acute angle to the front end of flange inner-face. CONSTITUTION:A rough shaped billet 10 is rolled by a break down mill to form a recessing part 12 without causing its deviation from the center of the outer face of a flange part 11. The projecting part 17 of a vertical roll 16 of the 1st stage in the next roughing universal mill, is fitted to the part 12. The face of projecting part 19 of a vertical roll 18 of the next stage is made to be parallel and stepped to its outside face 19a, and the part 12 is used as an introducing groove to bite the billet 10 between the rolls 18. Therefore, the width center of flange part 11 coincides accurately with the gap center between horizontal rolls 20. Further, an edger mill rolls the billet 10 so as to form an acute angle theta between the front-end face 21 and inner face 22 of flange. Accordingly, when the thick part 23 is correctingly rolled by an universal mill at the rear stage, the front-end shaped of flange is prevented from changing for the worse because the outer-face side of flange is remarkably extended.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a method for manufacturing H-section steel, and more particularly to a method for manufacturing H-section steel using a universal mill.

BACKGROUND OF THE INVENTION In general, a section steel having seven flange, such as an H section steel, is rolled by a universal mill having a pair of left and right vertical rolls and a pair of upper and lower horizontal rolls arranged in the same or almost the same vertical plane. The universal mill has 7 parallel flanges and is wide, easy to manufacture, and has good shape and dimensional accuracy.
Although it has various advantages such as uniform roll wear and easy roll turning, there is a problem when rolling H-section steel, which is that the center position in the width direction of the flange and the center position of the web thickness are It can be extremely difficult to roll to match. That is, as shown in a schematic cross-sectional view in FIG. If it deviates from the center of the gap in the vertical direction, the frictional force between the surface of the 7 flange portion 1 and the roll will be strong, whereas the strength at the base of the wear portion 2 relative to the flange portion 1 will be weak. When the wear part 2 is bitten,
The wear part 2 is moved vertically relative to the flange part 1 by the shear force, and as a result, the center of the flange width A-A and the center of the wear thickness B-8 are shifted by Δ as shown in FIG.
The product may be deviated by L.

In order to eliminate this inconvenience, the rolled material may be bitten by the rolls so that the center of the flange portion 1 coincides with the center of the gap between the horizontal rolls 3, that is, the pass line. As a method for this, Japanese Patent Publication No. 53-34585 has proposed a method of aligning the flange center position of the rolled material with the pass line by controlling a guiding device for each pass. However, this proposal This method requires a device for measuring the width of the flange, etc., a device for positioning the guiding equipment, and has the disadvantage that the equipment is complicated and expensive.

Furthermore, conventionally, a method has been known in which the relative positional deviation between the rolled material and the vertical rolls is reduced by changing the shape of the rolls without using any special equipment as described above. Briefly explaining the method, as shown in FIG. 10, a protruding part 5 is provided on the outer periphery of the central part of the vertical roll 4 to form a groove on the outer surface of the flange part 1. By fitting the protrusion 5 and the groove, the relative positional deviation between the rolled material and the vertical roll 4 is reduced.

Problems to be Solved by the Invention Although the conventional method described with reference to FIG. 10 has advantages such as not requiring special equipment, it has the following problems.

When producing H-shaped steel using a universal mill, first the rough-shaped steel slab is rolled into an H-shaped rough shape using a breakdown mill, and the obtained rough-shaped steel slab is sent to the rough universal mill.
is rolled with a roll having an H-shaped groove 7 as shown in FIG. The outer surface is generally convex, and the center portion is flat. Therefore, when the rough-shaped steel slab 6 is rolled with a universal mill having a vertical roll 4 having a protrusion 5 at the center of the outer periphery, as shown in FIG. 11(B), the overall rough-shaped steel slab 6 Since the protruding portion 5 is bitten into the central part of the outer surface of the flange which is convex, the biting position tends to shift vertically, and as a result, as shown in Fig. 11(C).
As shown in the figure, a deviation occurs between the center A-A of the flange portion 1 in the width direction and the center B-8 of the thickness of the wear portion 2. Such a deviation in the first pass can be corrected to some extent by shaping the tip of the flange using a subsequent edger mill, but the center part 8 of the recess made on the outer surface of the flange is located at the center of the flange width A- Since the center portion 8 of the recess remains displaced from A, the central portion 8 of the recess becomes a guide groove when the rolled material is bitten by the universal mill, resulting in the problem that the 7 flange portion 1 is displaced again.

In addition, in the above method of forming a depression on the outer surface of the flange portion 1 using the protruding portion 5 of the vertical roll 4, the thick portions formed at both the upper and lower ends of the flange portion 1 are corrected by rolling with a universal mill on the downstream side. In that case, the thick part is
As shown in D), the width widens, and the width on the outer surface of the flange portion 1 becomes wider than the width on the inner surface, resulting in the problem of deterioration of the so-called right-angled layer at the tip of the flange.

In view of the above-mentioned circumstances, the present invention has been developed to obtain an H-beam steel in which the center of the flange width and the center of the wear thickness can be made to coincide without the need for special equipment, and the shape of the flange tip is good. The purpose of this invention is to provide a rolling method that can be used.

Means for Solving the Problems In order to achieve the above object, the present invention creates a recess along the longitudinal direction in the center of the outer surface of the flange of the rough-shaped steel piece when obtaining the rough-shaped steel piece by breakdown rolling. While forming
In a rough universal mill, rolling is performed using a vertical roll with a protrusion on the outer periphery of the center of the roll body length, and in a rough edger roll, the angle between the rolling surface of the flange tip and the corresponding surface of the flange inner surface is an acute angle. This method is characterized by rolling.

In other words, in the method of the present invention, in a state where the shape of the rolled material is not yet determined, that is, during breakdown rolling, in addition to rolling into an H-shaped rough shape, a concave portion that will become the MFB portion is formed in the center of the outer surface of the flange. Therefore, the recess does not originally shift with respect to the center of the flange width, and therefore, the protrusion of the vertical roll in the rough universal mill engages with the recess, so that the rolled material does not move in the vertical direction. 21 into a rough universal mill without any deviation.

In addition, in the rough edger roll, rolling is performed so that the angle formed between the rolling surface at the tip of the flange and the surface corresponding to the inner surface of the flange is an acute angle, so the rolling surface at the tip of the 7 flange becomes a slope that slopes downward toward the outer surface side, and therefore, downstream When modifying the thick part with the universal mill on the side, the outer side of the flange end surface stretches, so the flange end surface, which was tilted in advance, approaches a flat surface, and as a result, the flange The perpendicularity of the tip is improved.

Embodiment In the method of the present invention, first, when rolling an H-shaped rough shaped steel piece 10 using a breakdown mill, as shown in the cross-sectional shape in FIG. A recessed portion 12 is formed along the line. As a method for this purpose, for example, as shown in FIG. 2, the center of the outer surface of the flange portion 11 is rolled by rolling the web portion 15 in the height direction using a box hole mold 14 having a bulging portion 13 formed at the bottom of the hole. A method can be adopted in which the recess 12 is formed in the center of the outer surface of the flange portion 11 by making a recess in the flange portion 11 and then performing a final breakdown rolling using a finishing hole die. As another method, as shown in Figure 3,
It is possible to adopt a method in which a depression on the outer surface of the flange, which is caused by the flange portion 11 falling outward during web inner width expansion rolling in the breakdown rolling, is used as it is as the recess 12 . In any of these methods, since the recesses 12 are formed at the same time as the breakdown rolling into a rough shape, the recesses 12 can be formed without misalignment with respect to the center of the outer surface of the flange portion 11.

The above rough shaped steel billet 10 is then rolled by a rough universal mill. The vertical rolls in the rough universal mill have a shape in which a protruding part is formed on the outer periphery of the central part of the body length, and the flange part is rolled by the vertical rolls. In addition,
The shape of the protrusion 17 of the first stage vertical roll 16 in the rough universal mill is preferably such that it fits into the recess 12 at the first bath, as shown in FIG. Also, the vertical roll 18 on the final stage side in the rough universal mill
Alternatively, in the vertical roll 18 of the intermediate universal mill, the surface of the protrusion 19 and the surface 19a outside it are parallel to each other, as shown in the fifth factor, in order to reduce the variation in the amount of reduction at each part of the flange thickness in the final rolling. It is also preferable that a protrusion 19 is formed on the outer periphery of the central portion of the body in a step-like shape and the height of the protrusion is lower than that on the upstream side. When rolling is carried out by these rough universal mills or intermediate universal mills, the recesses 12 serve as guide grooves and the steel strip 10 is caught between the rolls, and the recesses 1
2 is formed during breakdown rolling,
Since it is located precisely at the center of the outer surface of the flange, the center position of the flange portion 11 in the width direction and the center of the gap between the horizontal rolls 20 exactly match, in other words, the center of the flange width and the wear thickness. There will be no deviation from the center.

On the other hand, the tip of the flange portion 11 is rolled down by an edger mill, and in the edger mill placed close to the rough universal mill, the angle θ between the flange tip surface 21 and the flange inner surface 22 is as shown in FIG. Roll to form an acute angle as shown in . This is because when the thick wall portions 23 at both ends of the flange are corrected by rolling with a universal mill on the downstream side due to the formation of the recess 12, the outer surface of the flange noticeably extends in the width direction of the flange. This is to prevent deterioration of the flange tip shape due to
The angle formed by the flange inner surface corresponding surface 25 is set to an acute angle, and the flange tip FW portion rolling down surface 24 is formed in two stages as shown in FIG. 6 (a surface indicated by 24a and a surface indicated by 24b).
Rolling is performed so that the flange width on the outer surface side becomes narrower by tilting the flange.

Following the above-described rolling, the above-mentioned steel billet 10 is subjected to ordinary universal rolling to finally be finished into an H-section steel. When the thick portion 23 is rolled down in the thickness direction during the universal rolling, the width of the outer surface of the flange portion 11 is increased, but as described above, the portion of the inner surface of the flange tip is raised in advance. As a result of the width expansion, the flange end surfaces become approximately the same height on the inner and outer surfaces as shown in FIG. 7. Therefore, by shaping the tip of the flange using the edger roll in the universal mill group on the downstream side, the flange can be made to have a good shape such as perpendicularity.

Effects of the Invention As is clear from the above explanation, according to the rolling method of the present invention, the recesses on the outer surface of the flange that act as guide grooves are formed during breakdown rolling to obtain a rough-shaped steel piece. The concave portion precisely matches the center of the flange width, and the rough shaped steel piece is rolled by a rough universal mill having vertical rolls with a protrusion on the outer periphery of the center part of the O-ru body length. The rough-shaped steel piece can be bitten by the roll without causing any deviation, and therefore the center of the flange width and the center of the wear thickness can be accurately aligned. In addition, in this invention, since rolling is performed using an edger mill adjacent to the rough universal mill so that the angle between the tip end surface of the flange and the inner surface is an acute angle, the thick portions at both ends of the flange due to the formation of the concave portions are rolled in the rolling direction. Even if the flange width widens due to rolling and straightening, both the inner and outer sides of the flange end face will be at the same height, and as a result, the subsequent edge milling will prevent shapes such as squareness. Make it a good flange.

That is, in general, according to the present invention, it is possible to easily roll an H-section steel having a good shape and size without using any special equipment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the shape of a rough shaped steel piece obtained by the method according to the present invention, and FIG. 2 is a schematic diagram showing a method for forming recesses using a breakdown mill. Fig. 3 is a schematic diagram showing another example of the method of forming recesses by a breakdown mill, Fig. 4 is a schematic diagram showing the rolling state in the first bus of the rough universal mill, and Fig. 5 is a schematic diagram showing the rolling state in the first bath of the rough universal mill. A schematic diagram showing the rolling state at the R final stage side or the intermediate universal mill. Figure 6 is a partial view showing the rolled shape of the flange tip by the edger mill adjacent to the rough universal mill. Figure 7 is a partial view showing the rolling shape of the flange tip by the edger mill adjacent to the rough universal mill. Fig. 8 is a schematic diagram to explain the occurrence of misalignment of the wear part with respect to the flange part during the rolling process. Fig. 9 shows the center of the flange width and the web thickness. Fig. 10 is a cross-sectional view of an H-beam steel whose center is off-center, and Fig. 11 is a schematic diagram showing -13 of the conventional rolling method. Fig. 11 (A)
~(D> is a schematic drawing showing the rolling process by a conventional rolling method. FIG. 12 is a cross-sectional view showing the shape of a rough shaped steel piece obtained by breakdown rolling in a conventional rolling method. 10...Roughing Shaped steel piece, 11...flange part, 12
... recessed part, 15... web part, 16... vertical roll, 17... protrusion part, 21... flange tip surface, 22... flange inner surface, 23... thick part,
24...Flange tip reduction surface, 25...Flange inner surface corresponding surface, θ...Angle between the flange tip surface and the flange inner surface.

Claims (1)

[Claims] When manufacturing H-section steel by sequentially rolling the material using a breakdown mill, a rough universal mill, an intermediate universal mill, and a finishing universal mill, a recess along the longitudinal direction is created at the center of the outer surface of the flange of the rough-shaped steel billet during breakdown rolling. At the same time, the rough universal mill uses vertical rolls with a protrusion on the outer periphery of the center of the roll body length, and the edger roll close to the rough universal mill has a rolling surface that corresponds to the rolled surface of the flange tip and the flange inner surface. A method for manufacturing H-beam steel, which comprises rolling an H-beam steel at an acute angle with a surface.