JPS5937122B2 - Manufacturing method of shaped steel with protrusions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a section steel having a large number of protrusions on the outer surface of a flange.

Shaped steel is rarely used alone in architectural and civil engineering structures, but is often used in combination with concrete.

In that case, rather than using the section steel and concrete as separate structural members, it is advantageous in terms of strength to use them as a so-called composite member that is joined together.

In order to integrate the section steel and concrete, they need to be tightly connected to each other.

However, in reality, the adhesive force between the two members is small, and integration cannot be expected as it is.

Currently, as shown in the example of a composite beam structure, the method is to press shear connectors such as studs and dowels onto the H-beam flange that contacts the concrete slab, and use this to tightly connect the two. I am teaching.

By forming a large number of protrusions on the outer surface of the flange of a section steel by rolling, the section steel itself can have a binding force with concrete, making it possible to simplify the member and significantly improve construction.

BACKGROUND OF THE INVENTION Hitherto, lining plates have been known as H-shaped steel having protrusions on the outer surface of the flange, which are used for the purpose of covering the ground during road construction.

However, the surface protrusions of the lining board are intended to prevent slipping of vehicles, etc., and are not intended to be tightly bonded to concrete.

For lining boards, the height of the protrusions is not necessary, and is usually 1
．． 5 to 2.0 mynPj, degrees, and the protrusion angle is also 40° or less.

According to research by the present inventors, in order to obtain a concrete binding effect, it is necessary that the height of the protrusion be 2.0 mvt or more and the protrusion angle be 45° or more.

Furthermore, when forming protrusions on the lining board, even if the area to be indented is small, the purpose can still be achieved.
In order to exert a bonding force with the concrete, the area of the protruding portion must be less than % of the total area.

Next, in order to clarify the problems involved in manufacturing such a section steel, an outline of the manufacturing method will be explained using the H section steel rolling line shown in FIG. 1 as an example.

A typical H-beam rolling line consists of a heating furnace 1, a breakdown mill 2, and a rough universal mill 3, as shown in the figure.
In order to form protrusions on the outer surface of the flange, the outer surface of the flange is formed by the finishing universal mill 4. A large number of four parts may be provided on the outer surface of the vertical roll to be rolled down.

In order to form a protrusion height comparable to that of a conventional lining plate, the reduction amount is 1.5 to 2, and one OmmfG is sufficient, which is almost the same as the reduction amount during normal finish rolling, so there is no problem. few.

However, in order to form a protrusion height that achieves a bonding effect with concrete, the flange thickness reduction amount is required to be larger than normal finish rolling, and the flange thickness reduction rate is 0.
．． 20 or more.

The larger the flange thickness reduction rate, the easier it is to form a protrusion height, but there is a limit to the flange thickness reduction rate due to roll up due to the flange advancement and equipment constraints due to increased rolling power.

Under normal equipment constraints, it will be 0.35 or less. However, in order to obtain a bonding effect with concrete, the protrusion height,
In order to set the protrusion angle and the ratio of the protrusion area to the whole as described above, and to obtain a bonding effect with the concrete, it is necessary to increase the rolling reduction amount.

Therefore, a problem arises in that the height of the projections becomes uneven in the width direction of the flange.

Taking H-section steel as an example, FIG. 2 exaggerates this phenomenon of uneven protrusion height.

If a vertical roll is provided with a large number of recesses, the friction coefficient will increase if the outer surface of the flange is overlooked during rolling, and the metal flow in the width direction of the flange will increase.

The closer you get to the flange end, the greater the influence of this widthwise metal flow, and as a result, the protrusion is pulled down.

On the other hand, at the center of the flange, the height of the protrusion is lowered by a smaller amount due to the restraint of the web.

In this way, as shown in the figure, the height of the protrusion in the width direction of the flange becomes non-uniform.

Therefore, an object of the present invention is to obtain a method for manufacturing a shaped steel with projections in which the height of the projections in the flange width direction is uniform.

The method of the present invention locally increases the wall thickness of the flange end by increasing the edge reduction of the coarse universal mill group, thereby making the protrusion height uniform in the flange width direction.

Another method of the invention locally increases the wall thickness of the flange end by increasing the edge reduction of the coarse universal mill group and increasing the taper angle of the vertical rolls of the coarse universal mill, thereby Make the protrusion height in the flange width direction even.

Next, a method for preventing uneven protrusion height in the flange width direction will be explained.

Figure 3 shows the flange thickness reduction ratio (ψtf) and protrusion height ratio (
2 is a graph showing the results of an experiment to find the relationship between

The protrusion height ratio is the protrusion height hs of the material divided by the roll hole depth hR.

In the figure, the white circle (○) mark indicates the center of the H-section steel flange, the triangle (△) mark indicates the end of the flange, and the black circle (・) mark indicates the half position from the center to the end of the flange.・
represent.

As can be seen from FIG. 3, the protrusion height ratio increases in proportion to the seven-flange thickness reduction ratio, but in the case of H-section steel, the protrusion height ratio is difficult to achieve at the end.

This is because the protrusion height at the flange ends is lowered by the metal flow caused by the widening of the flange width, whereas the center part receives compressive stress in the rolling direction due to the restraint of the web, and the protrusion height tends to increase.

In order to make the protrusion heights uniform, the flange thickness reduction rate may be increased, but for reasons described later, it is desirable that the flange thickness reduction rate be as small as possible.

Rather, if the reduction at the flange end is locally increased,
The height of the protrusions can be made uniform without significantly increasing the reduction ratio of the entire flange.

Therefore, in the method of the present invention, in order to form a uniform protrusion height in the flange width direction, the rolling of the flange end is locally reduced by appropriately changing the vertical roll shape of the rough universal mill or by changing the rolling pass schedule. increase.

As one method, the reduction at the flange end can be locally increased by modifying the vertical roll outer surface taper of the rough universal mill as shown by the two-dot chain line in FIG.

The horizontal roll side surface and the vertical roll outer peripheral surface of the rough universal mill are 4 to 10 mm mainly due to the roll consumption rate.
° Tapered.

In the method of the present invention, the flange thickness reduction ratio in the finishing universal mill is increased toward the ends by further increasing the taper angle of the vertical rolls in the roughing universal mill.

The vertical roll modification amount is +2° for a flange width of 200mm, and +2° for a flange width of 300mm.
1° is sufficient to achieve the purpose.

However, if this method were to be effective on its own, the taper angle would become too large, which would interfere with normal H-shape rolling.

In order to locally increase the amount of reduction at the flange end, this can also be achieved by simply changing the rolling pass schedule without modifying the roll shape.

A regular coarse universal mill is paired with an Etziya mill.

The Etsuya Mill works by rolling down the flange ends to make the flange widths even.

It is already well known that when the end of a flange is rolled in an edge mill, the flange is deformed into a cocoon shape as shown by the two-dot chain line in FIG. 5 because the flange shape is vertically long.

Therefore, another method of the present invention actively utilizes this cocoon-shaped deformation to increase the amount of reduction of the flange end using a finishing universal mill.

FIG. 6 is a graph showing the experimental results for determining the relationship between the etching reduction rate (ψE) and the flange thickness increase rate (Δψtf).

The white circle (○) in the figure indicates the maximum flange thickness (tfmax).
The triangle (△) mark represents the flange minimum thickness (tfmin), and the black circle (·) mark represents the seven flange average thickness (tf).

The increase in the flange thickness increase rate Δψtf is the edging reduction rate ψ
It is proportional to E, and the larger the edging reduction rate ψE is, the more
The increase in the lunge thickness increase rate Δψtf is large.

However, when the etching reduction rate ψE becomes 0.1 or more,
The flange part buckles and rolling becomes unstable.

The etching reduction rate before finishing in the normal H-beam rolling process is ψE
-〇, about 0.01 to 0.02, but in order to increase the thickness of the flange end in order to make the protrusion height uniform,
According to the results of the inventors' study, the etching reduction rate ψE is 0.
．． 05 or higher is required.

Therefore, in the method of the present invention, the etching reduction ratio ψE of the edger mill before the finishing universal mill is 0.05 to
By selecting an appropriate value within the range of 0.10, it is possible to locally increase the wall thickness at the end of the flange and make the height of the protrusions attached to the flange uniform with a finishing universal mill.

In addition, when applying the method of the present invention, in order to minimize flange advance from the viewpoint of preventing roll up as much as possible, the flange thickness reduction rate should be as small as possible as long as the projection height is guaranteed. desirable.

Two methods have been described above to solve the problem.

Although sufficient effects can be obtained using these methods alone, even greater effects can be obtained by combining both methods.

Next, as an example, a specific embodiment based on the present invention will be shown.

Example target steel section: H section steel (450X200X9/14.) Projection shape: 4.5 squares x height 3 (mm) Projection pitch: 16X16 (mm) Hole shape: θ1-60° θ2-45° R= 0,00
8 RV pass schedule: Under the above rolling conditions, it was possible to form a protrusion shape with uniform protrusion height in the flange width direction on both flange sides.

Although the above explanation has been made by taking H-section steel as an example, the method of the present invention can also be applied to other section steels that can be finished with a universal mill.

As is clear from the above explanation, according to the method of the present invention, a shaped steel with projections that strengthens the bonding force with concrete, equalizes the height of the protrusions in the width direction of the flange, and guarantees the bonding effect is formed. can do.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a conventional H-beam rolling line. FIG. 2 is a schematic explanatory diagram showing non-uniformity in protrusion height in the flange width direction. FIG. 3 is a graph showing the experimental results for determining the relationship between the flange thickness reduction rate and the protrusion height rate. FIG. 4 is an explanatory diagram showing an example of modifying a vertical roll of a rough universal mill. FIG. 5 is an exaggerated view showing how the flange end is deformed into a cocoon shape by the edge mill. FIG. 6 is a graph showing the experimental results for determining the relationship between the etching reduction rate and the flange thickness reduction rate. 1: Heating furnace, 2-breakdown mill, 3: Rough universal mill group, 4: Finishing universal mill, 31:
Crude Universal Mill, 32: Etziya Mill.

Claims (1)

[Claims] 1. When forming protrusions on the outer surface of the flange of a section steel using a universal mill, the rolling reduction ratio ψE of the edger mill of the rough universal mill group is set to 0.05<ψE<0.1.
1. A method for manufacturing a shaped steel with protrusions, characterized in that the wall thickness of the flange end is locally increased by selecting from a range of 0, thereby making the protrusion height uniform in the flange width direction. 2. When forming protrusions on the outer surface of the flange of a section steel using a universal mill, the rolling reduction ratio ψE of the edge mill for the coarse universal pel group is set to 0.05<ψF<0.01.
Select from the range of 0, and set the vertical roll outer surface taber angle of the rough universal mill to 1 to 2 depending on the flange width of the product.
1. A method for manufacturing a shaped steel with projections, characterized in that the thickness of the flange is increased at the end by increasing the thickness in the angular range of 100°C, thereby making the height of the projections uniform in the width direction of the flange.