JP2784336B2 - Angle iron having projections on the outer surface of one flange and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle steel manufactured by hot rolling and having a large number of projections on the outer surface of one flange, and a method of manufacturing the same. This angle iron is suitable for use as a grating frame material (also referred to as an end angle) that covers roads, gutters inside and outside the building site, and the like.

[0002]

2. Description of the Related Art Hot-rolled angle irons (equal angle irons and unequal angle irons) specified in JIS G 3101 (1987) are widely used as general structural materials. The surface is usually smooth (flat). In the case of a steel plate, a steel bar, and an H-section steel, those having projections or stripes on the surface thereof have already been put into practical use, but no hot-rolled angle iron having projections on the flange surface has been found. In particular, in order to manufacture an angle steel having a projection or the like on only one outer surface of the flange, the hole shape is asymmetrical left and right with respect to the roll width direction, and the hole shape corresponding to the flange portion is 45 °. Due to the technical difficulties of rolling, the use of rolls having an inclined surface has not been produced so far. However, such angle irons are very suitable for the uses described below, and the development of the manufacturing technology has been desired.

In recent years, in residential land development and urban development, emphasis has been placed on beautification and security of road periphery. In particular, as for road gutters, gratings are rapidly spreading from the viewpoints of traffic safety and ease of management.

[0004] Grating is a grid-shaped groove cover that covers the opening of a gutter in a rainwater system inside or outside a road or a building site. Its structure varies depending on the structure and application of the upper part of the gutter,
Here, a description will be given by taking, as an example, grating that covers the opening of the most common U-shaped groove.

FIGS. 6A and 6B are views showing a grating covering the opening of the U-shaped groove, wherein FIG. 6A is a plan view, FIG.
(c) is an enlarged view of part C of (b), (d) is a view similar to (c) in the case where the angle steel according to the present invention described later is used as a frame, and (e)
FIG. 1 is a view showing a cross section of an angle iron according to the present invention. 1 is a grating, 2 is a frame material (end angle), 3 is a flat bearing bar, 4 is a cross bar, and 5 is a U-shaped groove. U
The grating 1 covering the opening of the U-shaped groove 5 is fixed by welding both ends 31 of the flat plate-shaped bearing bar 3 to the outside of one flange of the frame member 2 (angle iron), and furthermore, attached in parallel. The cross bar 4 is attached to the upper part of the bearing bar to form a lattice.

[0006] Recently, in order to prevent wheels of pedestrians and automobiles from slipping, gratings having projections 33 on the surfaces of bearing bars (also referred to as gratings with warts) have been developed and are already in practical use. However, as the frame member (end angle) 2, a normal angle steel having a smooth flange surface is used. The surface of the frame (the tread surface 22) is larger than the total surface of the bearing bar as the width of the gutter is smaller. Therefore, if projections (warts) are also provided on this surface, the effect of preventing the entire grating from slipping will be increased. For this reason, it is strongly desired to provide a projection on the tread of the frame material.

As a grating that meets this demand, a grating in which a non-slip projection is formed on a flat tread surface of a frame material by press molding has been proposed (see Japanese Utility Model Registration No. 3010509). However, in order to form a projection on a commercially available angle iron by press molding, a large-capacity press molding machine must be used, and there is a limit to the thickness of the flange of the angle iron that can be pressed. In addition, since the projection formed by press molding is recessed on the side opposite to the projection and has a reduced thickness, a hole is formed due to corrosion and wear. In addition, there is a disadvantage that large projections are sparsely distributed and the effect of preventing slippage is small. An even bigger problem is that the manufacturing process involves adding a separate process called pressing to make additional projections on the angle iron once formed, and a process that cannot be done continuously, which reduces the manufacturing cost of the angle iron itself. It is extremely bulky.

As shown in FIG. 6, the angle iron used for the grating frame material (end angle) has one flange serving as an end plate for welding and fixing both ends 31 of the bearing bar 3 and the other flange serving as an end plate. It becomes a tread for mounting the grating on the edge of the opening of the U-shaped groove. As for this frame material, it is desirable that there is a non-slip projection on the outer surface of one of the flanges to be the tread as described above, but the surface for fixing the other bearing bar is to perform welding reliably. Must be smooth. That is, in the angle steel for the grating frame material, the anti-slip projection needs to be provided only on one flange outer surface.

There are two main methods for producing angle irons. One is a method of producing hot rolled steel from a continuous casting bloom or the like by a hole mill, and the other is a steel strip obtained by slitting a hot-rolled steel sheet. This is a method for producing a lightweight angle iron by performing cold bending with a roll forming machine. The former has the advantage that the main process is a single process called hot rolling, which has excellent perpendicularity of the flange and can also produce a thick-walled angle iron.

FIG. 7 is a view showing a roll roll die (pass schedule) when a normal angle iron is manufactured by hot rolling. As shown in the figure, a group of rolling mills (finish rolling mills) having 6 to 8 holes using a continuous cast bloom (steel slab) to form a rough material using a breakdown mill.
And hot rolling is performed in 6 to 8 or more passes to form a mountain shape.

[0011] The following problems arise when attempting to produce an angle iron having a protrusion on the outer surface of one flange by the above-mentioned hot rolling method. That is, if the thickness of one flange is increased to increase the rolling reduction in order to form a projection having a sufficient height, the rolled material is bent because the product angle iron is asymmetric. Also, if the rolling reduction is increased, the rolled material may have flaws due to the advanced phenomenon of the material during rolling,
The projections are shaved by the mold and cannot form a sufficient height.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an angle iron having a large number of protrusions having a sufficient anti-slip effect on the outer surface of one flange, and which is particularly useful as the above-mentioned grating frame material. And a method for manufacturing such an asymmetric angle iron by hot rolling with high dimensional accuracy.

[0013]

Means for Solving the Problems The present invention provides an angle iron of the following (1) and (2), a grating frame material of (3), and
The summary of the method for manufacturing angle irons of (4) and (5).

(1) A hot-rolled angle iron having a large number of projections with an increased thickness on the outer surface of one flange (hereinafter, this angle iron is referred to as a “angle iron with projections”).

(2) The angle iron according to the above (1), wherein the end of the flange having the projection is inclined toward the back side and the thickness thereof is gradually reduced.

(3) A grating frame material made of the angled steel with projections as described in (1) or (2) above, wherein a flange surface having a large number of projections serves as a tread surface.

(4) The above (1) or (2) by hot rolling
A method for producing an angle iron with protrusions according to claim 1, characterized by comprising the following steps.

A step of forming a thickened portion having a trapezoidal cross section in the rolling direction by using a roll having a groove-shaped groove formed in a portion corresponding to one flange outer surface.

Forming a plurality of ridges in the rolling direction by rolling down the thickened portion using a roll having a plurality of grooved grooves formed in portions corresponding to the grooved grooves. .

The plurality of ridges are divided by rolling down with a roll having a recessed groove formed intermittently at a portion corresponding to the plurality of grooved grooves, thereby forming projections. Process.

(5) The above (1) or (2) by hot rolling
A method for producing an angle iron with protrusions according to claim 1, characterized by comprising the following steps.

A central portion of the flange is pressed down by using a roll having a groove-shaped groove formed in a portion corresponding to the outer surface of one flange, and a plurality of thickened portions having a trapezoidal cross section are formed in the rolling direction. Process.

Forming a plurality of ridges in the rolling direction by rolling down the thickened portions on both sides using rolls having grooved grooves formed on both sides of the grooved grooves.

Forming a large number of protrusions by dividing the plurality of ridges by rolling down with a roll having a concave groove formed intermittently in a portion corresponding to the groove-like groove. .

[0025]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a projection angle steel having a projection according to the present invention. FIG. 1 (a) is an angle iron having a truncated conical projection on one flange outer surface, and FIG. FIG. 1C is a view showing an angle iron having hemispherical projections, and FIG. There are no particular restrictions on the shape, size and arrangement of the projections. However, since the shape of the projection is determined by the shape of the hole cut into the roll, it is easy to cut as a hole, such as a truncated cone as shown in FIG. 1, a hemisphere cut out from a part of a sphere, or a truncated pyramid. Is desirable. Also, in order to provide a sufficient anti-slip function when used as a tread of a grating frame material, the height of the projections should be 1 mm or more, and the number (distribution density) will differ depending on the width of the flange. The ratio of the area of the bottom surface of the projection to the total area of the flange with the projection is preferably 30 to 50%.

When the angle iron with projections 2 as shown in FIG. 1 is used as a grating frame material (end angle), FIG.
As shown in (e), the flange 21 having a smooth outer surface becomes an end plate, and a bearing bar is welded and fixed to the outer surface. To perform this welding, as shown in FIG. 6 (e), a flat part
Is desirably provided. Further, the flange 22 having a projection on the outer surface is a surface parallel to a road surface called a tread surface. Therefore, as shown in FIG. 6 (e), the tip of the flange is inclined outward,
It is desirable to provide an inclined portion 26 and a corner radius 25 having a gradually decreasing thickness. By doing so, it is possible to prevent pedestrians from tripping when grating, and to make it easier for the wheels to get on. This angle iron is not necessarily equilateral, and one flange may be a non-equilateral angle iron wider than the other.

Next, according to the method of manufacturing the angle iron with projections of the present invention, the projection has a truncated cone shape (shown in FIG. 1 (a)).
Will be described as an example.

FIG. 2 is a diagram (a diagram showing a cross section of a roll hole die and a rolled material) showing an example of a forming and rolling pass schedule when the angled steel with projections of the present invention is manufactured.

FIG. 3 is a perspective view showing a shape of a rolled material formed in a forming rolling pass schedule when manufacturing the angle iron with protrusions of the present invention.

In the angle iron with projections according to the present invention, a coarse material is rolled from a continuous casting bloom or the like by a breakdown mill (not shown), and then a rolling pass schedule shown in FIG. Rolled and manufactured. Rolling by a breakdown mill and rolling in the second pass shown in FIG. 2 are performed in the same manner as in the case of normal angle iron rolling.

As shown in FIG. 2, in the third and fourth passes, a groove-like thickening die 63 is formed in a portion corresponding to one flange.
By using the upper roll 61 engraved with, the cross-section of the rolled material (both ends are pressed down) is formed into a trapezoidally thickened section. At this time, as shown in FIGS. 3 (c) and (d), the rolled material 7 has thickened portions 71, 7 having a trapezoidal cross section on one of the flanges.
2 is formed. The thickened portion 72 in FIG.
Trapezoidal height (thickness of flange) compared to the thickened part 71 of (c)
Is getting bigger.

The rolling in the fifth pass uses the upper roll 61 in which a plurality of groove-shaped forming holes 64 are engraved, and the thickened portion 72 is formed into a plurality of strips (three strips in the illustrated example) in the rolling direction. Rolling to split. By this pass, the rolling force is reduced, and a plurality of ridges 73 having a trapezoidal cross section and a large height are formed on a part of one of the flanges as shown in FIG. Note that the groove depth of the grooved hole type 64 is h ₁ <h in order to prevent the projection shape from being collapsed due to an advanced phenomenon, a widening phenomenon, and a difference in the roll peripheral speed at the projection position when the projection is formed in the next pass. ₂ <it is desirable that the h _3.

In the rolling in the sixth pass, in order to divide the plurality of ridges 73 in the direction perpendicular to the rolling direction, an upper roll 61 having a protruding hole die 65 engraved with a truncated cone is used as a rolled material. A plurality of truncated cone-shaped protrusions are formed. The depression with the projection hole type is
It is desirable to use a truncated cone with an apex angle of 100 to 120 °.
At this time, the rolled material 7 has a plurality of truncated conical protrusions 23 formed on a part of one flange as shown in FIG. 3 (f). If a hemispherical or truncated pyramid-shaped recess is formed as the projection hole die 65, an angle iron having hemispherical or truncated pyramid-shaped projections as shown in FIG. 1 (b) or (c) can be rolled. In the example shown in FIG. 2, the roll hole type in the sixth pass is set so that the tip of the flange with the projection is inclined outwardly in FIG. 6E.

One of the major features of the method of the present invention is that the thickened portions 71 and 72 are formed by pressing down one end of the flange at the third and fourth passes. As shown in Examples below, the thickness t ₂ of the thickened portion of the 3,4-pass may be approximately 10% greater than the thickness t ₁ of the other side. The formation of the thickened portion may be performed by rolling in one pass. However,
In this case, it is necessary to increase the rolling reduction in one pass. Therefore, it is desirable to perform the process in a plurality of passes as shown in the figure.

The portion having the increased thickness as described above is reduced into a plurality of grooves in the longitudinal (rolling) direction in the next fifth pass to be divided into a plurality of ridges. The thickness at the bottom of the groove formed at this time (t _{3 in} FIG. 3E) is the same as the thickness t _{1 on} the other side, and the thickness t ₂ of the ridge is the thickness of the fourth pass. the remains of t _2. And
In the finishing pass (6th pass), the ridges are cut in the horizontal direction, and FIG.
An angle steel with regularly formed projections as shown in (f).

According to such a rolling method, the reduction of the flange groove portion is performed separately for both ends and the central portion, and a projection having a sufficient height can be easily formed without applying excessive reduction in one pass. Can be formed. As a result, there is no problem such as a large bend in the rolled material, a defective shape of the projection, or generation of a flaw.

The rolling method described so far corresponds to the method (4), but in another embodiment, a groove is formed from the center of the flange to be protruded.
The method described above can also be adopted. FIG. 4 is a perspective view showing the shape of the rolled material formed by the method. This method is similar to the above steps in the first and second passes,
In the third pass, a thickened portion 71 is formed at both ends and a ridge is formed at the center, and at the fourth pass, both ends are pressed down to form a plurality of ridges 73. The projections can be formed in the same manner as described above.

[0038]

[Example] A steel slab having a side length of 120 mm in a cross section was heated to 1150 ° C, and the raw material (cross section 54
mm × 30 mm), and using a forming rolling mill and a finishing rolling mill, an angle iron with projections (nominal dimensions: flange thickness 5 mm, flange width 40 mm) according to the rolling pass schedule shown in FIG.
Was rolled.

FIG. 5 is a diagram showing the dimensions of the cross section of the rolled material in each pass in the forming and finishing mills. Table 1 shows the dimensions of the cross section of the rolled material rolled by these rolling mills.

[0040]

[Table 1]

As can be seen from FIG. 5 and Table 1, the outer diameter of one flange of the angle iron having a flange thickness of 5 mm and a flange width of 40 mm (both nominal dimensions) has a bottom diameter of 8.8 mm,
Three truncated cone-shaped protrusions having a diameter of 5.0 mm on the upper surface and a height of 1.5 mm were formed in the width direction at a pitch of 12 mm in the rolling direction. JIS for squareness of flange, fillet radius, etc.
(Japanese Industrial Standards).

A grating as shown in FIG. 6 was prototyped using the above angled steel with projections as a frame material (end angle). The bearing bar was welded to the smooth flange of the angle iron, and the assembly was assembled such that the flange with the projections became the tread surface to obtain the structure shown in FIG. It was confirmed that the grating has a significantly higher slip prevention effect than the conventional grating having a smooth tread surface of the frame material. Since a large number of projections on the tread are regularly arranged, the appearance is also excellent, and the pedestrian does not feel uncomfortable.

[0043]

The angle iron according to the present invention is an asymmetric angle iron having a protrusion on only one outer surface of the flange. In such a steel material, the flange side having the protrusion can be used for the purpose of preventing slippage or improving the adhesion of concrete, and the other smooth flange surface can be used as a joint surface with other members as in the related art. Although there are various uses of this angle iron, it is particularly suitable for use as a grating frame material (end angle) to enhance the anti-slip effect. The angle iron of the present invention,
According to the method of the present invention, it can be manufactured continuously and inexpensively by hot rolling.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an angle iron with projections of the present invention;
(a) is an angle iron having a truncated cone-shaped projection on one flange outer surface, (b) is also an angle iron having a hemispherical projection,
(c) is a figure which similarly shows the angle iron which has a truncated pyramid-shaped protrusion.

FIG. 2 is a view showing an example of a rolling pass schedule (a view showing a cross section of a roll hole die and a rolled material) when producing the angle iron with protrusions of the present invention.

FIG. 3 is a perspective view showing a shape of a rolled material formed in a rolling pass schedule when producing the angle iron with protrusions of the present invention.

FIG. 4 is a perspective view showing a shape of a rolled material formed by a groove in another embodiment when manufacturing the angle iron with projections of the present invention.

FIG. 5 is a diagram showing dimensions of a cross section of a rolled material in each pass in a forming rolling mill and a finishing rolling mill according to an embodiment of the present invention.

FIGS. 6A and 6B are diagrams showing grating covering the opening of the U-shaped groove, wherein FIG. 6A is a plan view, FIG. 6B is a cross-sectional view, and FIG. 6C is a partially enlarged view of FIG. (D) is a view similar to FIG. (C) when the angle iron according to the present invention is used as a frame material, and (e) is a view showing a cross section of the angle iron according to the present invention.

FIG. 7 is a diagram showing a roll roll die (pass schedule) when a conventional angle iron is manufactured by hot rolling.

[Explanation of symbols]

 1. Grating 2. 2. Angle steel with projection or frame material (end angle) Bearing bar 4. Crossbar 5. U-shaped groove 6. Rolling mill 7. Rolled material 21. Smooth flange (end plate) 22. Tread 23. Projection 73. Ridge

Claims (5)

(57) [Claims] 1. A hot-rolled angle iron having a large number of projections with an increased thickness on the outer surface of one flange. 2. The hot-rolled angle iron according to claim 1, wherein the end of the flange having the projection is inclined toward the back side, and the thickness thereof is gradually reduced. 3. A grating frame material made of the angle iron according to claim 1 or 2, wherein a flange surface having a large number of projections serves as a tread surface. 4. The method according to claim 1, wherein the hot rolling is performed.
2. A method for producing an angle iron according to claim 1, wherein the method comprises the following steps. A step of forming a thickened portion having a trapezoidal cross section in the rolling direction by rolling down both ends of the flange using a roll having a groove-shaped groove formed in a portion corresponding to one flange outer surface. Forming a plurality of convex portions in the rolling direction by rolling down the thickened portion using a roll in which a plurality of groove-shaped grooves are engraved in portions corresponding to the groove-shaped grooves. Forming a plurality of projections by dividing the plurality of ridges by rolling down with a roll having a concave groove formed intermittently in a portion corresponding to the plurality of groove-like grooves. . 5. The method according to claim 1, wherein the hot rolling is performed.
2. A method for producing an angle iron according to claim 1, wherein the method comprises the following steps. A step of pressing down the center of the flange by using a roll having a groove-shaped groove formed in a portion corresponding to one outer surface of the flange to form a plurality of thickened portions having a trapezoidal cross section in the rolling direction. Forming a plurality of ridges in the rolling direction by rolling down the thickened portions on both sides by using a roll having grooved grooves on both sides of the grooved grooves. Forming a plurality of projections by dividing the plurality of ridges by rolling down with a roll having a concave groove formed intermittently in a portion corresponding to the groove-like groove.