JPH10137856A - Bending method for steel and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bend an equal angle steel within the flat surface orthogonal to the symmetry axis of the V shaped cross section by using not the conventional hot bending method but the train of rolls. SOLUTION: Grooves 3 are provided in the outer peripheral surface coming into contact with the equal angle steel 1 of plural main rolls 2A, 2B arranged in zigzag in the longitudinal direction of the equal angle steel 1, and the lower end 1A of the inverse V shaped cross section shape in the state turned the angle steel 1 over and the one side 1B of the inverse V shaped cross section shape are restrained by coming into contact with the cross section of groves 3. Main rolls 2A, 2B are rotated to execute the bending operation under the restrained state. Also, the other side 1C of the lower end of the inverse V shape is restrained with an auxiliary roll 4 making a pair with main rolls 2A, 2B and provided with the angle steel 1 held, whereby such a deformation that the inverse V shape opens is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending process for a metal material, and more particularly to a process for bending a steel material, such as an angle iron, having only one axis of symmetry in a plane orthogonal to the axis of symmetry. The present invention relates to a method and an apparatus.

[0002]

2. Description of the Related Art Conventionally, in order to bend a steel material such as an H-section steel, main rolls 51A and 51B are staggered as shown in FIG. 8 and rotated while alternately contacting one outer surface of a steel material 53. Bending operation was performed. At this time, the inside of H of the H-section steel is pressed by the auxiliary roll 55 toward the main roll 51A.

[0003] Such a bending process is possible because, for example, this H-section steel has two symmetry axes, left, right and up and down in the figure, so that problems such as buckling and torsion hardly occur. It is. On the other hand, the angle steel shown in FIG. 9 is relatively easy to bend in the vertical plane in the figure, and although bending by a roll has conventionally been performed as shown in FIG.
The bending in the horizontal plane in the figure cannot be performed by bending as shown in FIG.

[0004] The reasons for this are that the angle irons move up and down, buckling occurs on the inner side of the bend in the V-shape of the angle irons, and the angle irons are twisted. Because there was. Such a problem occurs not only in the angle iron, but also in other steel materials having only one symmetric axis of the cross section (see FIG. 7). Conventionally, for angle iron, FIG.
The bending by the so-called baking method shown in FIG. That is, overheating and cooling are repeated in the local portion 57 on one outer surface of the cross section intermittently in the longitudinal direction of the angle iron.

[0005]

In the conventional baking method, the bending is not uniform and the bending accuracy is poor. The cross-sectional shape changes easily due to bending, and correction is required. heating,
The material of the cooling part changes. There are problems that the work efficiency is extremely poor and that skill is required. The present invention solves the above problems by using a row of rolls instead of a bending method to form a long steel material having a cross-sectional shape that can be fitted together in the direction of one symmetric axis in a plane orthogonal to the symmetric axis. It is an object of the present invention to provide a bending method and a device for bending at the same time.

[0006]

Means for Solving the Problems In order to achieve the above object, the inventors have made the following invention. The first invention is a bending process for bending a long steel material having an open cross-sectional shape that has only one symmetry axis in cross section and can be fitted to each other in the direction of this symmetry axis in a plane orthogonal to the symmetry axis. In the method, a plurality of main rolls arranged in a staggered manner in the longitudinal direction of the steel material and in contact with one outer surface are rotated, and the steel material is passed through the main rolls in an open cross-sectional shape while being bent and bent. The steel material is sent while being constrained by a groove provided on the outer peripheral surface of the main roll, and the cross section of this groove is
The bending method is characterized in that the restraining is performed in contact with a bottom portion and a single surface portion of the cross-sectional shape of the steel material in the prone state.

In a second aspect of the present invention, the steel material is an angle iron, the groove has a triangular cross section, and the bottom of the inverted V-shaped cross-sectional shape of the angle iron is in a protruding state. A bending method for a steel material, characterized in that the tip is in contact with one side of an inverted V-shape, which is a single-sided portion, to restrain the steel material.

According to a third aspect of the present invention, the cross section of the groove is
The lower end of the inverted V-shape of the angle iron is constrained by contacting one side of the inverted V-shape with one side of the inverted V-shape. Is a method for bending a steel material.

According to a fourth aspect of the present invention, the cross section of the groove is
This is a bending method for a steel material, characterized in that by extending a lower side of a triangular shape, both the lower end of the inverted V-shape of the angle iron and one side of the inverted V-shape are restrained.

According to a fifth aspect of the present invention, furthermore, a plurality of passes are made to pass between the plurality of main rolls, and the pressing amount of the main roll for performing the bending is determined by the pressing amount in the final pass with respect to the total pressing amount. Is 2 to 10%.

In a sixth aspect based on the third aspect, the steel material is an angle iron, and a cross section of the groove is a lower tip of an inverted V-shape which is a bottom of the inverted V-shaped cross-section of the angle iron in a prone state. And a shape that contacts one side of the inverted V-shape, which is one side, and restricts the cross-sectional shape.

In a seventh aspect based on the fifth aspect, the cross-section of the groove is formed such that one end of the lower end of the angle V steel has an inverted V shape.
It has a shape that makes contact with one side of the character and restrains it, and has an auxiliary roll that is provided in pairs with the main roll and sandwiches the steel material and restrains the other end of the lower end of the inverted V-shape of the angle iron. This is an apparatus for bending steel materials.

According to an eighth aspect of the present invention, a long steel material having an open cross-sectional shape which can have a cross section having only one axis of symmetry and which can be fitted to each other in the direction of this symmetry axis is formed in a plane orthogonal to the symmetry axis. In the bending apparatus that bends, a plurality of main rolls for processing that are staggered in the longitudinal direction of the steel material and are in contact with one outer surface,
It has a groove on the outer peripheral surface that is in contact with the steel material, and the cross section of this groove is
A bending apparatus for a steel material having a shape in which the open cross-sectional shape of a steel material is turned down and in contact with a bottom portion and one surface portion of the cross-sectional shape to restrain the cross-sectional shape.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIGS. 1 to 4 show Embodiment 1 of the present invention.
Will be described. In the first embodiment, an angle iron is used as a long steel material having a cross section having only one axis of symmetry and having a cross-sectional shape capable of fitting with each other in the direction of the axis of symmetry.

This angle iron is disposed around a segment piece constituting a segment that covers the inside of a tunnel excavated by a shield method, and is used for fitting adjacent segment pieces. That is, an angle iron having an angled V-shaped cross section provided in a convex shape and an angle iron having an angled V-shaped cross section provided in a concave shape facilitate connection of the segment pieces. is there.

Since the segment piece is curved in accordance with the shape of the tunnel, it is necessary to perform a bending process in accordance with the curvature. In the figure, the angle iron 1 is an equilateral angle iron (see FIG. 2 and FIG. 3), and has an inverted V-shaped cross-sectional shape that is opened downward with the symmetry axis of the cross section up and down, and in a horizontal plane (perpendicular to the symmetry axis). Bend in the plane). In the device into which the angle iron 1 is inserted, three main rolls 2A and 2B are staggered in rows in the longitudinal direction of the angle iron 1 (FIG. 1).

As shown in FIGS. 2 and 3, these main rolls 2A and 2B rotate around a vertical rotation axis, that is, a rotation axis parallel to the symmetry axis of the cross section of the angle iron 1. And
Grooves 3 generally called roll calibers on the rotating outer peripheral surface
Are formed. The groove 3 restrains the angle iron 1. Then, the angle iron 1 is rotated in a restrained state, and a bending force is exerted in a horizontal direction in a horizontal plane to perform bending.

The cross section of the groove 3 forms a triangle, and this triangle has a horizontal lower side 3A and an oblique side 3B. Main roll 2
B will be described as an example. Of these, the lower side 3A supports and restrains the bottom of the inverted V-shaped cross-sectional shape of the angle iron 1 in a protruding state, that is, the lower end 1A of the inverted V-shape (the lower left end in FIG. 2A). I do.
In addition, the oblique side 3B comes into contact with one side of the inverted V-shaped cross-sectional shape of the angle iron 1, that is, the one side 1B (the left side in FIG. 2A) of the inverted V-shaped and constrains.

Conversely, in the main roll 2A, the lower side 3A supports and restrains the lower V-shaped lower end 1C of the angle iron 1 (the lower left end in FIG. 3A). Also, the oblique side 3B is in contact with and constrains one side 1D (the left side in FIG. 3A) of the inverted V-shape of the angle iron 1. Thus, the buckling and twisting of the angle iron 1 can be prevented by the restriction by the groove 3 having the triangular cross section. Further, since the lower side 3A of the main rolls 2A, 2B supports the lower end 1A or 1C of the inverted V-shape in a wide range on a plane (see FIG. 1), the inverted V-shape of the angle iron 1 is vertically asymmetric. The tendency to bend downward due to bending,
We can hold down well.

The corners where the lower sides 3A of the main rolls 2A and 2B intersect with the outer peripheral surface are formed with a roundness r to make the tip of the angle iron 1 bite well. These main rolls 2A and 2B are adjusted by an adjustment mechanism (not shown) in order to adjust the distance between them so that the curvature of bending and the like can be changed.
It is supported so that it can move in a horizontal plane.

Auxiliary rolls 4A, 4B are provided in pairs with the main rolls 2A, 2B with the angle iron 1 interposed therebetween. These auxiliary rolls 4A and 4B restrain the other end of the inverted V-shaped lower end of the angle iron 1 or the like. This restraint prevents the angle iron 1 from buckling or twisting. Of these, auxiliary roll 4B
Is a pair with the central main roll 2B, has a cylindrical shape, and has a horizontal rotation axis.

The angle steel 1 is arranged outside the curved shape along the longitudinal direction in which the bending process is performed. Angle iron 1
Outside of the curved shape of the cross section, a stress is generated so that the inverted V-shaped cross section is closed.
C, that is, the side of the main roll 2B that is not restrained by the groove 3 is supported from below and restrained so as not to close.

The auxiliary roll 4A forms a pair with the main roll 2A, has a groove 5 having a shape similar to that of the main roll 2A, and has a vertical rotation axis. And it is arrange | positioned inside the curved shape along the longitudinal direction in which the bending process of the angle iron 1 is performed. The inside of the curved shape of the angle iron 1 generates a stress in which the inverted V-shaped cross section tends to open, so that the groove 5 of the auxiliary roll 4A is formed.
Is the other side 1B of the inverted V shape of the angle iron 1 (FIG. 3 (A)).
, And the other end 1A of the lower end of the inverted V-shape, that is, the other side that is not constrained by the groove 3 of the main roll 2A is supported from above, thereby restricting it from opening.

These auxiliary rolls 4A and 4B are used when there is a possibility that a shape defect after processing may occur, such as when the thickness of the angle iron is thin. However, when the angle iron has a sufficiently large thickness, it can be omitted. This will be described later in detail. In addition, on the entry side and the exit side of the angle iron 1 with respect to the main rolls 2A and 2B, twist prevention guide rolls 6 (FIG. 1) for restraining the angle iron 1 from above and below are provided to stabilize the pass line for feeding the angle iron 1. And to prevent the angle iron 1 from twisting.

(Operation) First, the distance between the main rolls 2A and 2B is adjusted by an adjustment mechanism (not shown) so as to change the curvature to a desired curvature. Next, the staggered main rolls 2A and 2B rotate. Then, the angle iron 1 is passed between the main rolls 2A and 2B in a state of an inverted V-shaped cross section in a state where the V-shaped cross section is turned down. Main roll 2A, 2B
Continues rotation while alternately contacting one outer surface of the angle iron 1 to feed the angle iron 1.

By this rotation, a bending force is applied to the angle iron 1 in the horizontal direction, and bending is performed in a horizontal plane. At this time, the angle iron 1 is restrained by the triangular cross-sectional groove 3 formed in the main rolls 2A and 2B, and buckling and twisting can be prevented. Further, since the inverted V-shaped cross-sectional shape of the angle iron 1 is asymmetric in the vertical direction, the angle iron 1
Has a tendency that the tip is warped downward. However, since the lower side 3A of the main rolls 2A and 2B supports the lower end 1A or 1C of the inverted V-shape in a wide range on a plane (see FIG. 1), it is possible to suppress the tendency to be warped downward. it can.

The angle iron 1 is, for example, the first main roll 2
If there is a slight tendency to warp downward after exiting A, the tip of angle iron 1 cannot bite well when fed to the next main roll 2B or 2A, as if There is a possibility that it will hit the vicinity of the corner of the lower side 3A of the groove 3 as it dive. However, since the roundness r is formed at the corner of the groove 3, the tip of the angle iron 1 is well rounded.
It is scooped up and makes good biting.

Further, the outside of the curved shape of the angle iron 1 to be bent generates a stress that the inverted V-shaped cross-sectional shape closes. By supporting the part of the roll 2B that is not restrained by the groove 3 from below by the auxiliary roll 4B, it can be prevented from being closed and can be prevented from being deformed.

On the contrary, the inside of the curved shape of the angle iron 1 is
The cross-sectional shape causes a stress to be opened, but the groove 5 of the auxiliary roll 4A is in contact with the other side 1B of the inverted V-shape of the angle iron 1 and the other 1A of the lower end of the inverted V-shape, namely By supporting the part of the roll 2A that is not restrained by the groove 3 from above, it is possible to prevent the roll 2A from opening and prevent deformation.

As described above, the auxiliary rolls 4A and 4B prevent the angle iron 1 from being deformed in the inverted V-shaped cross section, thereby further preventing the angle iron 1 from buckling or twisting. Further, twisting can be further prevented by providing a twist preventing guide roll 6 and restraining the angle iron 1 from above and below.

When the angle iron 1 is carried in and out of the apparatus shown in FIG. 1, a roller table including a large number of rollers is used. It is possible to prevent the angle iron 1 from falling down on the roller table and becoming unstable. In this way, the angle iron 1 is passed between the main rolls 2A and 2B. In this pass, the pass is generally regarded as one pass, and the pass is reciprocated a plurality of times for finishing.

[0032]

EXAMPLE An example belonging to the first embodiment will be described below. That is, the angle iron 1 and each roll 2A, 2B, 4A,
Specific dimensions such as 4B were adopted as shown in Table 1, and bending was actually performed. If the angle iron 1 has the same dimensions,
Diameters DA and DB of main rolls 2A and 2B, two main rolls 2
The curvature radius R of the bending process is determined by the interval L of A (see FIG. 1), the pushing amount h, and the like.

At this time, if the auxiliary roll is not used, the angle iron 1
The deformation (including buckling, twisting, improper squareness, etc.) of the inverted V-shaped cross-section of the above-mentioned shape depends on the thickness of the angle iron 1 and the diameter of the main rolls 2A and 2B. That is,
The deformation is less likely to occur as the thickness increases. Also, the main roll 2
If the diameter of A, 2B is large, the main rolls 2A, 2B
3A is the inverted V-shaped lower end 1A or 1 of the angle iron 1
Since C is supported in a wide range on a plane (see FIG. 1), the deformation hardly occurs.

Whether the deformation occurs depends more specifically on the ratio between the thickness and the shape of the angle iron 1 and the ratio between the diameter and the distance L of the main rolls 2A and 2B. That is, in the example of the third stage in Table 1, no deformation occurs even if the auxiliary roll 4A is not used, and the auxiliary roll 4 is not used in the fourth and fifth stages.
No deformation occurred even if neither A nor 4B was used. FIG. 4 is a graph showing boundary conditions under which deformation occurs based on such a relationship.

In FIG. 4, a plurality of data as shown in Table 1 are used. Further, the thickness dimension of the angle iron 1 is represented by t, the dimension B of one side of the inverted V-shaped cross-section is adopted as a representative of the shape dimension of the angle iron 1, and the ratio 両 者 ψ = t / B of the two is adopted. And the diameter dimension DA of the main rolls 2A and 2B,
Ratio of DB to interval L η η = (DA + DB) / 2 × (1 / L) = (DA + DB)
/ 2L is adopted.

As can be seen from FIG. 4, the larger ψ is,
Or, as η was larger, shape failure did not occur even without the auxiliary roll. Conversely, as 不良 was smaller or η was smaller, shape defects were more likely to occur without an auxiliary roll. However, in these cases as well, the use of the auxiliary roll can suppress the occurrence of shape defects.

[0037]

[Table 1]

(Other Embodiments) In the first embodiment,
The lower side 3A of the groove 3 of the main roll 2B supports and restricts one lower end 1A of the inverted V-shaped cross-section of the angle iron 1;
The other lower end 1C is supported by the auxiliary roll 4B and restrains the inverted V-shaped cross section from closing. However, in other embodiments, the auxiliary roll 4B is omitted as shown in FIG. The flange 7 of the roll 2B is widened, so that the groove 3
The lower side 3A may extend in the horizontal direction, support both lower ends 1A, 1C of the inverted V-shaped cross section, and restrain the inverted V-shaped cross section from being closed (FIG. (B)). This also prevents the inverted V-shaped cross section of the angle iron 1 from closing, that is, not falling down. The main roll 2
A is the same as in the first embodiment (FIG. 1).

As described above, since the auxiliary roll 4B can be omitted, the distance L between the two main rolls 2A can be reduced, and therefore, even if the diameters DA and DB of the main rolls 2A and 2B are reduced.
It is possible to prevent the ratio η from becoming small. That is, shape defects can be reduced even with the small main rolls 2A and 2B.

In the above embodiment, the angle steel may be passed through the apparatus only once, but is generally passed plural times. In this case, the pushing is performed separately from the pushing amount h (see FIG. 1). From the experimental results of the inventor, it has been found that when the pushing amount Δh at the time of the final pass is reduced, shape defects such as torsional deformation caused by the previous pass are corrected.

That is, as shown in the graph of FIG. 6, the horizontal axis represents the ratio Δ of the pressing amount Δh in the final pass to the total pressing amount h.
h / h (hereinafter referred to as a final pass pressing amount ratio) is taken. The amount of twist is plotted on the vertical axis. The amount of torsion is expressed as the amount of torsion (mm) with respect to the dimension (m) in the longitudinal direction of the angle iron. A plurality of data as shown in Table 2 where the total number of passes was 3 and 4 was obtained and a graph was drawn. As can be seen from this graph, when the final pass pushing amount ratio Δh / h is 2 to 10%, the twist is 0.1%.
It is 5 mm / m or less, which indicates that the shape defect can be sufficiently corrected.

[0042]

[Table 2]

Further, in the above embodiment, the long steel material having a cross section having only one axis of symmetry and having a cross section that can be fitted to each other in the direction of the symmetry axis is an angle steel 1 having a V-shaped cross section. However, the present invention can of course be implemented with other steel materials.

For example, as shown in FIG. 7, the cross section has a V shape narrower than the 90-degree V shape of the angle iron (FIG. 7).
(A)) or one having a wide V-shape (not shown). Further, the cross section may be substantially U-shaped and the bottom may be flat (FIG. 7 (B)) or may be round (FIG. 7 (C)). Further, a semicircular cross section (FIG. 7D) may be used. Further, the cross-sectional shape may be substantially W-shaped (FIG. 7E).

Even with these steel materials having the cross-sectional shape shown in FIG. 7, the grooves provided on the outer peripheral surface of the main roll are restrained by contacting the bottom and one side of the cross-sectional shape of the steel material in a prone state. It has the same effect as the above embodiment. Further, in the above embodiment, three main rolls are staggered, but in other embodiments, four or more main rolls can be staggered.

[0046]

As described above, in the present invention,
Rather than the conventional bending method, it is possible to use a row of rolls to bend a long steel material having a cross-sectional shape that can fit in the direction of one symmetry axis in a plane orthogonal to the symmetry axis. it can. Therefore, as compared with the conventional baking method, the bending becomes uniform, the bending accuracy can be improved, the cross-sectional shape does not easily change, no correction is required, and the material does not change. In addition, continuous bending is possible, work efficiency is good,
Moreover, it does not require much skill.

[Brief description of the drawings]

FIG. 1 is a plan view of a roll row showing an apparatus according to an embodiment of the present invention.

FIG. 2A is a view showing a main roll 2B constituting the apparatus shown in FIG. 1;
(B) is a front view of (A).

FIG. 3A is a view showing a main roll 2A constituting the apparatus shown in FIG. 1;
(B) is a front view of (A).

FIG. 4 is a diagram showing a graph of boundary conditions at which a shape failure occurs in a cross-sectional shape of the steel sheet based on specific dimensions of an angle steel, each roll, and the like at the time of actual bending.

5A is a plan view of a roll row showing an apparatus of another embodiment, FIG. 5B is a side view of a main roll 2B constituting the apparatus of FIG. 5A, and FIG. 2) is a side view of a main roll 2A constituting the device.

FIG. 6 is a diagram showing a graph of an appropriate range of a final pass reduction ratio when an angle steel is actually bent.

FIGS. 7A to 7E are views showing cross sections of steel materials in which the present invention can be implemented.

FIG. 8 is an explanatory diagram of bending of an H-section steel by a roll of a conventional technique.

FIG. 9 is an explanatory diagram of bending of an angle iron by a conventional bending method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angle iron (steel material) 2A, 2B Main roll 3, 5 groove 4A, 4B Auxiliary roll 6 Twist prevention guide roll

Claims (8)

[Claims] 1. A bending method for bending a long steel material having an open cross-sectional shape having a cross section having only one axis of symmetry and capable of fitting with each other in the direction of the symmetry axis in a plane orthogonal to the symmetry axis. In this method, a plurality of main rolls arranged in a staggered manner in the longitudinal direction of the steel material and in contact with one outer surface are rotated, and the steel material is bent by passing between the main rolls in a state where an open cross-sectional shape is turned down. The steel material is fed while being constrained by a groove provided on the outer peripheral surface of the main roll, and the cross section of the groove is in contact with the bottom portion and one surface portion of the cross-sectional shape of the steel material in the prone state to perform the constraining. Characteristic bending method. 2. The steel material is an angle iron, the cross section of the groove has a triangular shape, and a lower V-shaped lower end which is a bottom of the inverted V-shaped cross section of the angle iron in a protruding state, and a single-sided portion. 2. The method according to claim 1, wherein the restraining is performed by contacting one side of the inverted V-shape. 3. An auxiliary section provided with a cross section of the groove in contact with one of the lower end of the inverted V-shape of the angle iron and one side of the inverted V-shape to form a pair with the main roll and sandwich the steel material. Roll is reverse V
3. The other lower end of the character is restrained.
Bending method of the steel material described. 4. The cross-section of the groove extends by extending a lower side of a triangle so as to contact and constrain both the lower end of the inverted V-shape of the angle iron and one side of the inverted V-shape. Item 4. A method for bending a steel material according to Item 2. 5. A plurality of passes for passing between a plurality of main rolls are performed, and a pressing amount of the main roll for performing a bending process is a ratio of a pressing amount in a final pass to a total pressing amount of 2-1.
The method for bending steel material according to claim 1 or 2, wherein the amount is 0%. 6. The steel material is an angle iron, and a cross section of the groove is
The inverted V which is the bottom of the inverted V-shaped cross section of the angle iron
4. The steel bending apparatus according to claim 3, wherein the lower end of the character has a shape in contact with one side of the inverted V-shape, which is a single-sided portion, to restrict the cross-sectional shape. 7. A cross section of the groove has a shape in which one end of an inverted V-shape of the angle iron comes into contact with one side of the inverted V-shape to restrain, and a pair is formed with a main roll to sandwich a steel material. 6. The steel material bending apparatus according to claim 5, further comprising an auxiliary roll provided for restraining the other of the inverted V-shaped lower end of the angle iron. 8. A bending apparatus for bending a long steel material having an open cross-sectional shape which has a cross section having only one axis of symmetry and can be fitted to each other in the direction of the symmetry axis in a plane orthogonal to the symmetry axis. In, a plurality of main rolls for processing that are staggered in the longitudinal direction of the steel material and are in contact with one outer surface, have a groove on the outer peripheral surface that is in contact with the steel material, and the cross section of the groove has an open cross-sectional shape of the steel material. An apparatus for bending a steel material having a shape that contacts a bottom portion and one surface portion of the cross-sectional shape in a state and restricts the cross-sectional shape.