JPH08290321A - Electro-resistance-welded pipe cutting method and manufacture thereof - Google Patents

Abstract

PURPOSE: To prevent the generation of crush deformation to a cut part at the time of cutting a rectangular pipe into specified length by a cutter press after manufacturing this rectangular pipe by rolling and electro-resistance-welding. CONSTITUTION: An opening part 25 for relaxing the thrust stress of the cutter 20 of a cutter press 10 is previously formed at a rectangular pipe P. This opening part 25 is placed in such a way as not to intersect a part L subjected to electro-resistance-welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting an electric resistance welded pipe and a method for manufacturing the same.

[0002]

2. Description of the Related Art For example, electric resistance welded pipes are widely used for supporting columns of racks having a plurality of upper and lower shelves and construction materials. This electric resistance welded pipe is manufactured by roll-forming a strip-shaped material with a roll-forming machine. It should be noted that what is used as a support of a rack is generally a square pipe, and it is required that the length dimension has a certain degree of accuracy and that both ends thereof are neatly cut.

As one of the methods of cutting the electric resistance welded tube to a predetermined length, there is a method using a press cutter. In this method, as shown in FIG. 19 (a), the electric resistance welded pipe P is cut into a guillotine shape by a cutter C having a plate-shaped and inverted triangular blade portion orthogonal to the longitudinal direction thereof. . In this case, the top of the blade portion of the cutter C is made to coincide with the electric sewn portion L formed along the longitudinal direction of the electric sewn pipe P.

[0004]

In the above-mentioned cutter press, the end portion of the electric resistance welded pipe P caused by cutting is shown in FIG. 19 (b).
Since the V-block-shaped crushing deformation as shown in FIG. 1 may occur, the electric resistance welded pipe P needs to be subjected to the end treatment again thereafter. Therefore, it is troublesome, and there is a problem that the effective utilization rate as the strip-shaped material is reduced due to the deformed portion that is discarded along with the end treatment.

Therefore, as a countermeasure against the above first problem to be solved, the present applicant opens the cutting position of the electric resistance welded pipe P with a width substantially equal to the thickness of the cutter C as shown in FIG. It has been conceived to form the breakage inducing portion 25 that is formed. The breakage inducing portion 25 is formed by forming a notch at a predetermined position (position to be cut by the cutter C) by a punching press or the like at the stage of the band plate material before roll-forming the electric resistance welded pipe P. Can be provided.

By taking such measures, it was possible to prevent the end portion of the electric resistance welded pipe P cut by the cutter press from being crushed and deformed. However, when the strip-shaped raw material after the notch is formed into a tubular shape by roll forming and then the seam is to be welded, as shown in FIG. 20, a welding defect B is formed around the opening of the fracture inducing portion 25.
It was found that The main reason for this is that the magnetic field due to the welding current is disturbed and
It is considered that this is because at the position corresponding to, the phenomenon of concentrating so as to surround the opening edge is brought about.

According to the present invention, it is possible to cut the electric resistance welded pipe by the press cutter without requiring the end treatment as described above, thereby increasing the effective utilization rate of the strip plate material (the first solution). In addition to solving the problem), a method for cutting the electric resistance welded pipe and a method for manufacturing the electric resistance welded pipe (which is a second problem to be solved) capable of preventing welding jump among the means for solving the problem are also provided. And

[0008]

In order to achieve the above object, the present invention takes the following technical means. That is, the present invention according to claim 1 (a method for cutting an electric resistance welded pipe) is a method for cutting an electric resistance welded pipe with a press cutter, and a fracture inducing portion is previously provided at a proper position in the cutting progress direction of the cutter with respect to the electric resistance welded pipe. The feature is that it is provided.

The breakage inducing portion is formed by an opening substantially corresponding to the wall thickness of the cutter, a plurality of slits or notches, a recess, or an appropriate combination thereof. It is a thing.
With this configuration, when the cutter for cutting the electric resistance welded pipe reaches the breakage inducing portion, the cutting stress is relaxed, and the cutting can be facilitated. Therefore, the end of the electric resistance welded pipe caused by the cutting is not crushed and deformed.
That is, this can solve the first problem to be solved.

The breakage inducing portion is provided without breaking the electric resistance portion formed in the longitudinal direction of the electric resistance welded pipe (claim 2). That is, when the breakage inducing portion is an opening or a slit penetrating the tube wall with a width substantially corresponding to the thickness of the cutter, at least in the width direction with respect to the strip-shaped raw material before roll-forming into the tube shape. A welding side edge portion is provided on one side portion in a state where there is residual thickness (claim 3).

When such a strip-shaped material is roll-formed into a tubular shape, the seam portion formed along the longitudinal direction is not interrupted even by the side edge portion left on the side of the fracture inducing portion. Become. Therefore, when this seam is welded, welding failure such as cutting of the electric seam portion does not occur. On the other hand, if the notch or recess is formed by thinning the tube wall with a width substantially equivalent to the wall thickness of the cutter as the fracture inducing part, direct it in the width direction with respect to the strip plate material before roll forming into the tube shape. It is also possible to provide it (claim 4).

When such a strip-shaped material is roll-formed into a tubular shape, the joint portion formed along the longitudinal direction does not penetrate the pipe wall even at the portion intersecting the fracture inducing portion. However, it does not have a discontinuity. Therefore, even when this seam is welded, welding failure such as cutting of the electric-welded portion does not occur. It is also possible to provide such a notch or a breakage inducing portion on the inner surface side of the pipe.

On the other hand, according to the present invention of claim 5 (a method for manufacturing an electric resistance welded pipe), a strip plate material supply portion, a processing portion for performing a predetermined accessory process on the strip plate material, and the strip plate. In a method for producing an electric resistance welded pipe through a roll forming part for forming a tubular material into a pipe shape, a welding part for welding a seam after forming, and a cutting part for cutting the electric resistance welded pipe after welding to a predetermined length The fracture inducing portion according to any one of claims 1 to 4 is formed in the processed portion.

As described above, the fracture inducing portion can be formed at the same time by the processing portion which performs a predetermined accessory processing on the strip-shaped material.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 showing the production line of the electric resistance welded pipe P
In the figure, 1 is a supply unit for the strip-shaped material W, which has an uncoiler 2, a roller leveler 3, and a roll feeder 4, and 5 is a hole, a cut-and-raised part, an unevenness, etc. It is a processing unit that performs auxiliary processing of, and is configured by a press machine. Reference numeral 6 denotes a roll forming section for forming the strip plate material W into a tubular shape, and is formed by arranging a plurality of forming rolls in a row. Reference numeral 7 is a welded portion for welding a seam formed along the longitudinal direction of the pipe after forming it into a tubular shape.

Numeral 10 is a cutting portion for cutting the electric resistance welded pipe P after passing through the welding portion 7 at every predetermined length and is constituted by a press cutter. The electric resistance welded pipes P cut by the cutting section 10 are appropriately carried out by a carry-out section 11 such as a conveyor. FIG. 6 shows the cutting section 1
0 shows a press cutter used as a traveling cutting machine, and while the carriage 14 travels at the same speed as the electric resistance welded pipe P along the upper and lower guide rails 12 and 13. The electric resistance welded pipe P (not shown in FIG. 6) is cut by the cutter portion 15 provided in the unit 14. Cutter part 15
Is a cutter frame 1 provided at predetermined intervals as shown in FIG.
A cutter 20 having a thickness substantially the same as the distance between 8 and 19 is vertically moved. Reference numeral 21 denotes a through hole through which the electric resistance welded pipe P is passed, and a frame-shaped chamfered portion 22 is provided at an opening edge portion on the inlet side.
Has been applied.

1 to 4 show a method of cutting the electric resistance welded pipe P according to the present invention. Prior to the cutting by the cutting part 10, the fracture induction part 25 is preliminarily provided in the electric resistance welded pipe P. It is provided. As shown by a chain double-dashed line in FIG. 3, the electric resistance welded pipe P is formed into a rectangular rectangular pipe by bending both side portions of the strip plate material W in the width direction upward by the roll forming portion 6 (one point in the figure. The chain line indicates a polygonal line portion), and the electric welding portion L by the welded portion 7 is formed at the center of the upper surface thereof. The fracture inducing portion 25 has the electric welding portion L as shown in FIGS. 1 and 2. Opening 27 that penetrates the pipe wall at both sides of the
And a notch 28 in which the tube wall is thinned at a position intersecting with the electric resistance portion L.

The opening 27 is provided so as to remove a corner portion of the electric resistance welded pipe P. The width of the opening 27 (the dimension along the longitudinal direction of the electric resistance welded pipe P) is the same as that of the cutting portion 1.
The cutter 20 is formed to have a thickness substantially equal to that of the cutter 20. In addition, the notch 28 is formed in the left and right openings 27.
2 are provided so as to be connected to each other in correspondence with the width dimension thereof, and are formed in a V-shaped groove shape as shown in FIG. Therefore, the pipe wall 29 is left between these notches 28, and thus the notches 28 do not cause welding failure (see B in FIG. 20), that is, the electric seam L is not cut off. It is a thing.

The opening 27 and the notch 28 are
By the processing part 5 in the above-mentioned production line of the electric resistance welded pipe P (see FIG. 5), the band plate-shaped material W can be provided by pressing or the like. That is, in FIG. 3, the openings 27 are provided on both sides in the width direction of the strip plate material W so that at least the respective side edges thereof are left for welding. The length of the left and right openings 27 (the widthwise dimension of the strip plate material W) is limited to such a degree that the strip plate material W is not bent (deformed or cracked) during bending during roll forming. Need to be kept. Therefore, it is not preferable to connect both openings 27 to each other.

On the other hand, the notch 28 is formed from each opening 27.
The strip plate material W is provided so as to extend outward in the width direction and pass through to the side edge thereof. The notch 28 may be provided on the lower surface of the strip plate material W (the surface which is the outer peripheral surface of the electric resistance welded pipe P) in the state shown in FIG. The inner peripheral surface of P) may be provided, or in some cases, it may be shallowly provided on both upper and lower surfaces.

Since the breakage inducing portion 25 (opening 27 and notch 28) is provided in the electric resistance welded pipe P as described above, the welding defect B as shown in FIG. 20 does not occur in the welded portion 7. . Therefore, in the cutting section 10, the cutting along the breakage inducing section 25 is easily and surely performed as the cutter 20 advances (falls). Of course, at this time, the electric resistance welded pipe P does not undergo a V block-shaped crush deformation as shown in FIG. 19B.

The present invention is not limited to the above embodiment. For example, as the breakage inducing portion 25 provided on the electric resistance welded pipe P, the following various types can be adopted.
That is, the fracture inducing portion 25 shown in FIG. 8 does not have the opening 27 and is configured by only two notches 28.

The notch 28 may be formed so as to surround the entire circumference of the electric resistance welded pipe P, or may be formed only within a predetermined range on the left and right around the electric resistance welded portion L. The breakage inducing portion 25 shown in FIG. 9 is provided so as to extend to the right and left sides centering on the electric-welded portion L in a predetermined range.
It is composed of a slit 30 of a book. Needless to say, the slit 30 is formed so as to penetrate the tube wall.

The slits 30 can be connected at appropriate positions in the longitudinal direction by notches 28 on the side surface or the upper surface of the electric resistance welded pipe P. Even if the slit 30 is provided so as to intersect with the electric-welded portion L, the welding width of the electric-welded portion L is not caused because the slit width is very small. The fracture inducing portion 25 shown in FIG. 10 is a groove-shaped concave portion 3 having a thin wall.
It is composed of 1. The recess 31 is formed by the electric resistance welded pipe P.
It is also possible to form it so as to surround the entire circumference thereof, and it is also possible to set it to a predetermined range on the left and right around the electric sewn portion L. The recess 31 may be the outer peripheral surface or the inner peripheral surface of the electric resistance welded pipe P.

The breakage inducing portion 25 shown in FIG.
However, in the case of a deformed rectangular pipe having a stepwise cross-sectional shape, the opening 27 on one side (left side in FIG. 11) with respect to the electric seam L is formed wide so as to span a plurality of corners. is there. By doing so, the high rigidity region due to the corner portion is balanced with the other portion. The breakage inducing portion 25 shown in FIG. 12 is configured as one opening 27 provided in a portion where the cutter 20 first comes into contact. The openings 27 are arranged on the opposite side of the electric sewing portion L so that they do not intersect with each other.

That is, as shown in FIG. 13, the strip plate material W at the stage before roll-forming the electric resistance welded pipe P is
The opening 27 is positioned at the center in the width direction. The breakage inducing portion 25 shown in FIGS. 14 and 15 is also configured as one opening portion 27 provided at a portion where the cutter 20 first abuts similarly to the one shown in FIGS. 12 and 13. Moreover, the opening 27 does not intersect with the electric sewn portion L. However, the opening 2
7 is different from that of FIGS. 12 and 13 in that it has a relation of being arranged adjacent to the electric sewn portion L.

The fracture inducing portion 25 shown in FIG.
Although 0 is configured as one opening 27 provided at a portion that first comes into contact, this opening 27 intersects the electric sewn portion L. Therefore, as shown in FIG. 17, the strip plate material W for the electric resistance welded pipe P has the opening 27, that is, the breakage inducing portion 25 formed by notching both side edges in the width direction.

Even in this case, the dimension in which the opening 27 intersects the electric resistance portion L (the dimension along the longitudinal direction of the electric resistance pipe P).
It is preferable that the welding defect be suppressed to the smallest possible range by making the value as small as possible. The cross-sectional shape of the electric resistance welded pipe P is not limited to the above-mentioned square pipe or odd-shaped (stepped or the like) square pipe, and may be a round pipe or the like as shown in FIG. 18, for example. Note that the arrows X, Y, and Z in FIG. 18 show an arrangement example of the electric sewn portion L.

The detailed structure of the manufacturing line shown in FIG. 5 and the detailed structure of the cutting section 10 shown in FIGS. 6 and 7 are not limited in any way. Needless to say, the shape of the cutter 20 in the cutting portion 10 can be appropriately changed according to the configuration of the fracture inducing portion 25, the forming region (opening shape, etc.), the forming position, the cross-sectional shape of the electric resistance welded pipe P, and the like. (See FIG. 11, etc.).

[0030]

As is apparent from the above description, claim 1
In the described invention (cutting method of the electric resistance welded pipe), since the breakage inducing portion is provided in advance at a proper position in the cutting progress direction of the cutter with respect to the electric resistance welded pipe, the cutter for cutting the electric resistance welded pipe is When the fracture-inducing portion is reached, the cutting stress is alleviated, and the cutting can be facilitated. Therefore, the end of the electric resistance welded pipe caused by the cutting is not crushed and deformed. That is, this can solve the first problem to be solved.

In the rupture inducing portion, the openings or slits provided in the strip-shaped material are arranged in a predetermined manner (claim 3) or are formed as notches or recesses (claim 4) so that they are generated in the longitudinal direction after roll forming. If the seam is not interrupted, it is possible to prevent the electric seam from being cut off (Claim 2), that is, it is possible to prevent defective welding. As a result, the second problem to be solved can be solved.

As a result, it is not necessary to perform a large end treatment on the electric resistance welded pipe after cutting, so that the manufacturing can be facilitated and the manufacturing cost can be reduced. Further, since a large amount of end treatment is not required, the amount of waste as the band plate material can be reduced, and the effective utilization rate can be increased. On the other hand, according to the present invention of claim 5 (a method for manufacturing an electric resistance welded pipe), a strip plate material supply section, a processing section for subjecting the strip plate material to a predetermined accessory process, and the strip plate material are provided. In a method for producing an electric resistance welded pipe through a roll forming part for forming a pipe shape, a weld part for welding a seam after forming, and a cutting part for cutting the electric resistance welded pipe after welding to a predetermined length, the processing Since the above-mentioned fracture-inducing portion is formed in the portion, there is an advantage that the fracture-inducing portion can be formed without adversely affecting the production efficiency of the electric resistance welded pipe.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view showing an implementation situation of a cutting method according to the present invention.

FIG. 2 is a perspective view showing an electric resistance welded tube used in the cutting method of the present invention.

FIG. 3 is a perspective view showing a strip-shaped material for forming the electric resistance welded pipe shown in FIG.

FIG. 4 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 5 is a side view showing a production line of an electric resistance welded pipe.

6A and 6B are views showing a press cutter used for a cutting part in a manufacturing line, in which FIG. 6A is a front view thereof and FIG. 6B is a side view thereof.

FIG. 7 is an enlarged perspective view showing a cutter portion of the press cutter.

FIG. 8 is a perspective view showing a first modification of the breakage induction part.

FIG. 9 is a perspective view showing a second modification of the breakage inducing portion.

FIG. 10 is a perspective view showing a third modification of the fracture inducing portion.

FIG. 11 is a front sectional view showing how the cutting method of the present invention is applied to a deformed rectangular pipe-shaped electric resistance welded pipe.

FIG. 12 is a front cross-sectional view showing an implementation state of the cutting method of the present invention with respect to a fourth modification of the fracture inducing portion.

FIG. 13 is a perspective view showing a strip-shaped material for forming the electric resistance welded tube shown in FIG.

FIG. 14 is a front cross-sectional view showing an implementation state of the cutting method of the present invention with respect to a fifth modification of the fracture inducing portion.

FIG. 15 is a perspective view showing a strip-shaped material for forming the electric resistance welded tube shown in FIG.

FIG. 16 is a front cross-sectional view showing an implementation state of the cutting method of the present invention with respect to a sixth modification of the fracture inducing portion.

17 is a perspective view showing a strip-shaped material for forming the electric resistance welded tube shown in FIG.

FIG. 18 is a front cross-sectional view showing a situation in which a breakage inducing portion is provided for a round pipe-shaped electric resistance welded pipe.

FIG. 19 (a) is a front sectional view showing a conventional cutting method, and FIG. 19 (b) is a front sectional view showing an example in which an electric resistance welded tube is crushed and deformed by cutting.

FIG. 20 is a perspective view illustrating a situation where welding failure occurs in an electric resistance welded pipe due to a fracture inducing portion.

[Explanation of symbols]

 1 Supply Part 5 Machining Part 6 Roll Forming Part 7 Welding Part 10 Cutting Part 20 Cutter 25 Breakage Inducing Part 27 Opening 28 Notch 30 Slit 31 Recess P P ERW Pipe L ERW Part W Strip Plate Material

Claims (5)

[Claims] 1. A method of cutting an electric resistance welded pipe (P) with a press cutter, wherein the cutter (2) is attached to the electric resistance welded pipe (P).
A method for cutting an electric resistance welded pipe characterized in that a breakage inducing portion (25) is provided in advance at an appropriate position in the cutting direction of (0). 2. The electric resistance sewing according to claim 1, wherein the fracture inducing portion (25) is provided without cutting the electric resistance portion (L) formed in the longitudinal direction of the electric resistance welded pipe (P). How to cut the pipe. 3. The fracture inducing portion (25) is provided with a cutter (2).
The opening (2) that penetrates the pipe wall with a width substantially corresponding to the wall thickness of
7) or slits (30), and the fracture inducing portions (25) are welded side edge portions on at least one side portion in the width direction with respect to the strip plate material (W) before roll-forming into a tubular shape. The method for cutting an electric resistance welded pipe according to claim 2, wherein the electric resistance welded pipe is provided in a state in which the remaining portion is left. 4. The cutter (2) is provided with the breakage inducing portion (25).
0) is a notch (28) or a recess (31) having a wall thickness reduced by a width substantially corresponding to the wall thickness of 0), and the fracture inducing portion (25) is a strip plate shape before roll-forming into a tube shape. The method of cutting an electric resistance welded pipe according to claim 1 or 2, wherein the method is provided in the width direction with respect to the material (W). 5. A strip plate material (W) supply part (1) and a processing part (5) for subjecting the strip plate material (W) to a predetermined accessory process.
And a roll forming part (6) for forming the strip plate material (W) into a tubular shape, and a welding part (7) for welding the joint after forming.
In the method for manufacturing an electric resistance welded pipe (P) through a cutting portion (10) for cutting the electric resistance welded pipe (P) after welding to a predetermined length, the processing portion (5) is characterized in that Item 5. A method for manufacturing an electric resistance welded pipe, which comprises forming the fracture inducing portion (25) according to any one of Items 4.