JPH05269582A - Device for manufacturing resistance welded tube - Google Patents

Abstract

PURPOSE:To improve heating electricity efficiency and to manufacture even a small size tube by arranging an induction coil at the position close to a couple of pressure rollers. CONSTITUTION:Tube raw material 1 is formed into a tubular shape having a V-shaped gap and the edges in opposition of the V-shaped gap are subjected to electric welding continuously on a welding point where these edges are pressurized and joined together by the couple of pressure rollers 19. Axes parts are provided integrally, respectively on the upper and lower parts of roller parts provided with tubular grooves on the whole peripheral side parts of columns with insulating material such as ceramics as material to form the pressure rollers 19. The upper and lower axes parts of the pressure rollers 19 are supported freely rotatably on respective sliding blocks 12 whose mutual interval is arranged in a row so that it can be adjusted movably, the pressure rollers are arranged in a row at a necessary interval and the induction coil is arranged on the position close to the couple of pressure rollers. Consequently, the temperature of a V-seam weld zone of the tube raw material is raised, even the small size tube can be manufactured and the quality of the resistance welded tube is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved high frequency electric resistance welded pipe manufacturing apparatus for rolling a metal strip to form a tubular body.

[0002]

2. Description of the Related Art A conventional induction type electric resistance welded pipe manufacturing apparatus is shown in FIG.
It was constructed as shown in FIGS. As shown in the schematic view of FIG. 8, this is a pair of pressure rolls 2 arranged opposite to each other while bending a tube material 1 which is a strip-shaped metal plate so as to be rolled into a tubular shape.
It is inserted between a and 2b, and the tube material 1 is moved in the direction of arrow S in the figure. At this time, the seam guide 3 is inserted between the opposed edge portions 5a and 5b of the tube material 1 on the front side of the pressure rolls 2a and 2b as viewed in the traveling direction of the tube material 1 to form the V-shaped gap 5. To do. At a predetermined position of this V-shaped gap 5, an induction coil 6 is arranged so as to surround the outer circumference of the tube material 1.

A high frequency current I is caused to flow from the power source 7 to the induction coil 6 so that the induction current i induced in the tube material 1 is caused to flow to the opposite edges 5a and 5b of the V-shaped gap 5. The edges 5a and 5b are heated so that the temperature of the V seam welding point 4 portion reaches near the melting point.

Further, the V-shaped gap 5 is closed by the pressure rolls 2a and 2b, and the V seam welding point 4 where both edges 5a and 5b contact each other is pressed.

In this way, at the V seam welding point 4, both edge portions 5a and 5b are heated to near the melting point and are simultaneously pressure-welded to perform welding joining. In addition, a bite 9 for bead cutting was arranged on the downstream side of the welding point 4, and the weld bead 8 rising on the outer peripheral side of the welded portion was cut off to manufacture an electric resistance welded pipe.

In the conventional apparatus constructed as described above, as shown in FIG. 11, the pressure rolls 2a and 2b are provided with the annular groove 10 having a semicircular cross section slightly larger than the outer diameter of the electric resistance welded pipe on the entire peripheral side portions thereof. , A shaft hole 11 is bored along the rotation axis.

A pair of pressure rolls 2 formed as described above
As shown in FIGS. 9 and 10, a and 2b are used by being attached to the slide block 12 on the roll stand 15. That is, the shaft rods 13 are inserted into the shaft holes 11 of the pressure rolls 2 a and 2 b, and the shaft rods 13 are inserted into the two bearings 14.
Each slide block 12 is attached to the corresponding slide block 12 via the.

The pair of left and right slide blocks 12 are mounted on the roll stand 15 so as to be slidable in a transverse direction at right angles to the traveling direction S of the tube material 1. A pair of roll stands 15
Is configured so that the mutual spacing can be adjusted by a screw feeding device. Therefore, a through hole penetrating horizontally through the pair of slide blocks 12 is bored, and the feed screw rod 16 is passed through the through hole. Then, as shown in the drawing, the two slide blocks 12 are provided with a female screwing portion 1 in which a left-hand thread to be screwed into the feed screw rod 16 is cut.
7 and the right-threaded female screw portion 17 are attached. Then, by rotating the handle 18 provided on the feed screw rod 16, the mutual interval between the left and right slide blocks 12 can be moved and adjusted.

With the above-mentioned structure, the pressure rolls 2 symmetrically provided on the left and right slide blocks 12 are provided.
a and 2b are a circular hole-shaped lateral diameter length formed by combining the two annular grooves 10 of the tubular material 1 through which the circular hole-shaped portions are passed by adjusting the mutual spacing between the left and right slide blocks 12. The edge portions 5a, 5b facing each other can be adjusted so as to apply an appropriate pressing force (so-called upset) toward the center thereof.

[0010]

In order to perform efficient welding by using the conventional electric resistance welded pipe manufacturing apparatus as described above, FIG.
It is necessary to make the distance l _V from the induction coil 6 to the center of the pressure rolls 2a and 2b and the width l _C of the induction coil 6 as small as possible. This is for the following reasons. First, the induction current i generated by the induction coil should flow into the V-shaped gap 5 of the tube material 1 and heat it. However, as shown in FIG. 12, the induced current i
Is shunted depending on the current-carrying resistance (mainly the current-carrying length) of the portion where the current flows, and a part of the current is circulated from the outer peripheral surface of the tube material 1 facing the induction coil 6 to the inner peripheral surface thereof. The circumferential portion of the material 1 is heated and lost, which not only significantly lowers the heating electric efficiency, but also increases the current shunting to the inner circumferential surface, resulting in the edge 5a of the V-shaped gap, 5
If the current flowing through b decreases, the edges 5a and 5b cannot be heated or welded. Therefore, by shortening the lengths of the distances l _V and l _C in comparison with the distance of the inner peripheral surface of the tube material 1, the ratio of the induced current i flowing in the V-shaped gap 5 portion is increased, and the heating electricity is increased. It seeks to improve efficiency.

For the above reason, the conventional apparatus has been devised so as to shorten the distance l _V in particular, but there is mechanical interference between the induction coil 6 and the pressure rolls 2a and 2b and the slide block 12. The diameter of the pressure rolls 2a and 2b, the slide block, and the like cannot be made smaller than the current one unless the diameter is made smaller.

The pressure rolls 2a and 2b press the tube material 1 formed by bending a strip-shaped material into a tube. That is, from the width of the original pipe material 1, the circular circumference after welding is pressed so as to reduce the plate thickness by about the plate thickness. Therefore, in order to give this strong pressure contact force to the tube material 1, the strength of the shaft rod 13 that has passed through the shaft holes 11 of the pressure rolls 2a and 2b and the bearing 14 portion of the slide block 12 that supports this shaft rod 13 is increased. It must be kept at a specified high strength.

For this reason, if the outer diameter of the pressure rolls 2a, 2b is made smaller than the current one, the shaft hole 11 and the shaft rod 13 must be made thinner. When the shaft diameter of the shaft rod 13 becomes thin, its strength is insufficient and it cannot withstand the reaction force for press-contacting the tube material 1, causing shaft bending, which causes poor welding accuracy of the tube material 1. Further, even if the pressure rolls 2a and 2b are made small and the induction coil 6 is made to approach them, the slide block 1
Since the ball bearings and roller bearings as the bearings 14 for supporting the shaft rod 13 are incorporated in the slide block 2, the slide block 12 cannot be miniaturized. Since the coil 6 hits the slide block 12 and cannot be further approached, the distance l _V cannot be shortened beyond a certain value in the configuration of the conventional device.

Under these circumstances, when a pipe material 1 having a diameter of 7 mm or less is to be welded by the conventional apparatus, the distance l _V × 2 corresponding to the length of the V-shaped gap 5 is equal to the inner peripheral surface of the pipe material 1. Since it becomes relatively longer than the distance, welding by effective electric heating of the edge portions 5a, 5b cannot be performed and the pipe material 1 is heated over the entire circumference, so that the material is softened and the pressure rolls 2a, 2b.
The pressure cannot be applied by b, and the tube material 1 is oxidized. Alternatively, the V entry angle of the V-shaped gap 5 in the pipe material 1 cannot be maintained stably, which results in poor welding. Therefore, there is a problem that the conventional device cannot manufacture an electric resistance welded pipe having a diameter of 7 mm or less.

In view of the above points, the present invention reduces the pressure roll to improve the heating and electric efficiency, and the pipe diameter is 7 mm.
It is an object of the present invention to newly provide an electric resistance welded pipe manufacturing apparatus capable of manufacturing the following small diameter pipes.

[0016]

In the electric resistance welded pipe manufacturing apparatus of the present invention, first, an insulating material such as ceramic is used as a material, and shafts are respectively provided above and below a roll portion in which an annular groove is formed on the entire circumferential side portion of a cylinder. The pressure rolls are formed integrally with each other, and the upper and lower shafts of the pressure rolls are axially inserted into the shaft holes of the supporting members in the slide blocks arranged in parallel so that the mutual intervals can be adjusted. It is characterized in that a pair of pressure rolls are mounted side by side with a required gap, and an induction coil is arranged at a position close to the pair of pressure rolls.

Secondly, the present invention constitutes a pressure roll in which an insulating material such as ceramics is used as a material, and a shaft portion is integrally formed above and below a roll portion in which an annular groove is formed in the entire circumference of a column, By constructing a pair of pressure rolls at a predetermined interval and supporting the shaft portion of the pressure rolls, the pair of pressure rolls can be mounted in the roll case and the induction coil can be arranged at a position close to the pair of pressure rolls. It is characterized by

[0018]

With the above-described structure, the outer diameter of the pressure roll, the slide block, and the like can be significantly reduced, so that the distance from the induction coil to the center of the pressure roll can be reduced and the V seam welded portion can be reduced. Improve heating efficiency,
By preventing the induction current from flowing in the circumferential direction of the tube material, the production speed can be greatly improved and the power consumption rate can be reduced. Further, since the temperature of the V seam welded portion of the pipe material can be raised and the temperature rise of other portions can be suppressed, the quality of the electric resistance welded pipe can be improved and the pipe diameter 7 which has been impossible in the past.
It is possible to make pipes with a small diameter of less than mm.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electric resistance welded pipe manufacturing apparatus of the present invention will be described below with reference to FIGS. 1 to 7, parts corresponding to those of the conventional example shown in FIGS. 8 to 12 are designated by the same reference numerals, and detailed description thereof will be omitted. 1 to 4 showing a first embodiment of the present invention, 1 is a pipe material, 4 is a V seam welding point, 5 is a V-shaped gap, 6 is an induction coil, 12 is a slide block, 16 is a feed screw rod. 17 is a female screw portion, and 19 is a pair of left and right pressure rolls.

The pressure roll 19 is integrally formed of a ceramic material as a whole, and is provided with shafts 19b above and below a central roll 19a. The pressure roll 19
Other than this, may be made of an insulating material. Roll part 19a
Is a cylindrical column having a large diameter, and an annular groove 10 having a semicircular cross section, which is slightly larger than the outer diameter of the electric resistance welded tube, is formed on the entire circumferential side portion thereof. Shaft 1
Reference numeral 9b is a columnar shape and is integrally provided above and below the roll portion 19a so as to be coaxial therewith.

Each pressure roll 19 constructed as described above
Is pivotally mounted so that the roll portion 19a is located between the two support members 20 fastened in parallel to each slide block 12 with a predetermined gap. The support member 20 is a thick member having a substantially trapezoidal shape in a plan view, and has a shaft hole 21 at a sharp corner portion thereof.
Perforated. And as shown in FIG. 1, the pressure roll 1
9, the upper shaft portion 19b of the drawing is directly inserted into the shaft hole 21 of the upper supporting member 20 of the drawing, and the lower shaft portion 19b of the drawing is directly inserted into the shaft hole 21 of the lower supporting member 20 of the drawing to apply pressure. The roll 19 is supported so as to be rotatable.

If the dimensions allow, bushes 22 made of oilless metal or special bearing metal may be installed in each shaft hole 21, as shown in FIG.

As shown in the drawing, the pressure rolls 19 axially attached to the slide blocks 12 are arranged such that their roll portions 19a are aligned in parallel, and the roll portions 19a are arranged in parallel. Make fine adjustments so that the distance is appropriate. In this way, the pipe material 1 is passed through the round hole portion formed by the annular grooves 10 being aligned between the parallel roll portions 19a to apply a pressing force to the V seam welding point 4.

Looking in the direction of travel of the tube material 1 indicated by the arrow S,
The induction coil 6 is arranged near the front side of the pressure roll 19. At this time, the outer diameter of the pressure roll 19 can be reduced from 1/2 to 1/3 in comparison with the conventional minimum roll. Further, since the bearing for supporting the shaft portion 19b of the pressure roll 19 is unnecessary, the pressure roll 19 can be exposed to the end of each slide block 12.
Therefore, the distance l _V from the induction coil 6 to the center of the pressure roll 19 can be reduced to about half of the conventional minimum distance.

Therefore, the ratio of the current i flowing in the V-shaped gap 5 portion of the tube material 1 is greatly improved as compared with the ratio of the current flowing in the circumferential direction of the tube material 1, and the edge of the tube material 1 is increased. It is possible to improve the heating efficiency of the unit and reduce the electric power consumption, which is the amount of electric power input. Further, since the temperature increase in the circumferential direction of the pipe material 1 is small, the temperature of the whole pipe material 1 can be lowered and the quality of the pipe can be improved. Also,
This makes it possible to make small-diameter pipes that cannot be made by conventional devices. Further, since the pressure roll 19 is an insulating material such as ceramic, the pressure roll 19 is not induction-heated even if the induction coil 6 is brought close to it, so that a cooling device for the pressure roll 19 is unnecessary. it can.

Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, a pair of pressure rolls are incorporated into a cassette type roll case to be integrated. The pressure roll 19 used in this example has the same structure as that of the first embodiment described above. That is, the whole is made of an insulating material such as a ceramic material, and the annular groove 10 is formed on the entire circumference side portion of the large-diameter cylindrical roll portion 19a. Cylindrical shaft portions 19b are integrally formed coaxially above and below the roll portion 19, respectively.

The roll case 23 is made of metal, non-magnetic material, or ceramic, and the upper case 23a and the lower case 2 are formed.
3b and 3b form a substantially rectangular case. As shown in the figure, the lower case 23b is provided with a pressure roll 19 at the center of a thick member and a space for passing the tube material 1. Axial holes 21 are formed at predetermined two locations near the end on the induction coil 6 side of the support portion 24 corresponding to the bottom plate portion in the space portion. In addition, this shaft hole 21
If the dimensions allow, bushings for bearings may be installed in the part. Through holes 25 for reference fixing bolts are formed in both lateral thick portions of the lower case 23b.

The upper case 23a is a plate member formed in the same shape as the lower case 23b in a plane, and is located at a position corresponding to the two shaft holes 21 and the two through holes 25 in the lower case 23b so as to be vertically coaxial. The two shaft holes 21 and the two through holes 25 in the support portion 23a are bored. In addition, a trapezoidal notch 26 as shown in the drawing is formed in a portion between the two shaft holes 21 at the end portion of the induction coil on the support portion of the upper case 23a, and the V of the pipe material 1 is passed through the notch 26. Make the seam weld point 4 visible. Further, the notch portion 26 is for releasing spatter scattered during welding to the outside.

Then, the shaft portion 19b under each pressure roll 19 is inserted into each shaft hole 21 of the lower case 23b, and the shaft portion above each pressure roll 19 is inserted into each shaft hole 21 of the upper case 23a. 19b is axially inserted, the upper case 23a is overlaid on the lower case 23b, and they are integrally combined as shown in FIG.

The pressing force to be applied to the V seam welding point of the tube material 1 by the pair of pressure rolls 19 is the roll case 2
It is a fixed type in which the distance between the shaft holes 21 provided in No. 3 is adjusted in advance by setting it to an appropriate distance.

The roll case 23 having the pair of pressure rolls 19 mounted thereon is placed on the roll stand 15 with the through holes 25 penetrating the reference fixing bolts 27 mounted on the roll stand 15, as shown in FIG. It is installed by tightening with the nut 27a. Various roll cases 23 are prepared according to the type of the tube material 1, and they are appropriately exchanged for use.

In the present embodiment constructed as described above, the outer diameter of the pressure roll 19 can be reduced to about half that of the conventional one, and by mounting it in the compact roll case 23, the induction coil 6 can be removed from the pressure roll 19. The distance l _V to the center of the can be reduced to about half of the conventional one, and wasteful power consumption can be suppressed, electric efficiency related to welding of the pipe material 1 can be greatly improved, power unit can be reduced, and production speed can be increased. It can be greatly improved.
Furthermore, since the temperature rise in the circumferential direction of the tube material 1 can be reduced, the temperature of the tube material 1 as a whole can be lowered and the product quality can be improved.

Further, it is possible to make a small-diameter pipe which has been impossible in the past, and it is particularly effective for making a small-diameter pipe made of a non-ferrous material (for example, copper, aluminum, etc.).

In addition, since the pair of pressure rolls 19 are preliminarily attached to the roll case 23, it is not necessary to adjust the pressure applied to the tube material 1, and it is possible to make the reaction force of the pressure strong. Moreover, a slide block or the like is not necessary, and the device can be simplified. Further, since the pressure roll 19 is made of an insulating material such as ceramic, the pressure roll 19 is not induction-heated even if the induction coil 6 is brought close to the pressure roll 19, so that a cooling device for the pressure roll 19 is unnecessary. it can.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other structures can be adopted without departing from the gist of the present invention.

[0036]

As described above in detail, the production of the electric resistance welded pipe of the present invention
According to the device, first, an insulating material such as ceramic is used as a material.
The upper and lower sides of the roll part where the circular groove is formed on the entire side of the cylinder.
A pressure roll is formed by integrally forming the shaft of each
And slides arranged side by side so that the mutual distance can be adjusted.
The block supports the upper and lower shafts of each pressure roll.
It is mounted in a state that it is inserted in the shaft hole of the member, and
So that they are parallel to each other with a required space, and
The induction coil is placed close to the
To reduce the distance from the induction coil to the center of the pressure roll.
To improve the heating efficiency of V seam welded parts
The production speed is set so that the induced current does not flow in the circumferential direction of
Can be greatly improved and the power consumption rate can be reduced.
Has the effect of In addition, the V seam welded part of the pipe material
Do not increase the temperature of the circumference of other pipes by raising the temperature.
Since it is possible to do so, it is a small diameter pipe that can not be made by conventional pipe making.
But it is said that it enables pipe making and improves the quality of ERW pipes.
effective.

Secondly, the present invention constitutes a pressure roll in which an insulating material such as ceramics is used as a material, and a shaft portion is integrally formed above and below a roll portion in which an annular groove is formed in the entire circumference of a column, By constructing a pair of pressure rolls at a predetermined interval and supporting the shaft portion of the pressure rolls, the pair of pressure rolls can be mounted in the roll case and the induction coil can be arranged at a position close to the pair of pressure rolls. Therefore, the distance from the induction coil to the center of the pressure roll is reduced to improve the heating efficiency of the V seam welded part and prevent the induction current from flowing in the circumferential direction of the pipe material, thus increasing the production speed. There is an effect that the power consumption rate can be improved and the power consumption rate can be reduced. Also,
Since the temperature of the V seam welded part of the pipe material can be raised and the temperature rise of other parts can be suppressed, the quality of the electric resistance welded pipe can be improved, and pipes of small diameter can be made, which was previously impossible. In particular, there is an effect that it is possible to favorably make a small-diameter pipe made of a non-ferrous material (copper, aluminum, etc.).

In addition, since the pair of pressure rolls are installed in the roll case in advance, it is not necessary to adjust the pressing force to be applied to the tube material, and a high strength against the reaction force against this pressing force is required. Can hold Moreover, since a pair of pressure rolls can be handled for each roll case, the replacement work can be facilitated, and a mechanism such as a slide block for adjusting the distance between the pair of pressure rolls can be eliminated and the structure can be simplified. is there.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a first embodiment of an electric resistance welded pipe manufacturing apparatus of the present invention.

FIG. 2 is a plan view of a main part of the above embodiment.

FIG. 3 is a front view showing the pressure roll portion of the above embodiment taken out.

FIG. 4 is a cross-sectional view of a main part showing another configuration example of the pressure roll support portion of the above embodiment.

FIG. 5 is a perspective view of essential parts showing a second embodiment of the electric resistance welded pipe manufacturing apparatus of the present invention.

FIG. 6 is a plan view of an essential part of the above embodiment.

FIG. 7 is a vertical sectional view taken along the line AA of FIG. 6 of the above embodiment.

FIG. 8 is a perspective view of a main part illustrating a conventional electric resistance welded pipe manufacturing apparatus.

FIG. 9 is a vertical cross-sectional front view of essential parts of the conventional device.

FIG. 10 is a vertical cross-sectional front view of a main part of a slide block portion of the conventional device.

FIG. 11 is a partial cross-sectional front view showing the pressure roll of the above conventional device.

FIG. 12 is a vertical cross-sectional explanatory diagram of a portion through which a tube material passes through an induction coil when induction heating is performed by the above conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pipe material 4 ... V seam welding point 5 ... V-shaped gap 6 ... Induction coil 10 ... Annular groove 12 ... Slide block 19 ... Pressure roll 19a ... Roll part 19b ... Shaft part 20 ... Support member 21 ... Shaft hole 22 ... Bush 23 ... Roll case 24 ... Support part 25 ... Through hole

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[Procedure amendment]

[Submission date] June 5, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

Claims (2)

[Claims] 1. A welding point at which a tubular material is formed into a tubular shape having a V-shaped gap, and the opposite edges of the V-shaped gap are joined by the edges being pressed by a pair of pressure rolls. In an electric resistance welded pipe manufacturing device that continuously performs electric welding with a shaft, by using an insulating material such as ceramic as a material, and by integrally providing shaft portions above and below a roll portion provided with an annular groove on the entire circumferential side portion of the cylinder, The upper and lower shafts of the pressure rolls are rotatably supported by the respective slide blocks that are arranged in parallel so that the pressure rolls can be moved and adjusted so that the pressure rolls are arranged in parallel at the required intervals. The electric resistance welded pipe manufacturing apparatus is characterized in that an induction coil is arranged at a position close to the pair of pressure rolls. 2. A welding point in which a pipe material is formed into a tubular shape having a V-shaped gap, and the opposite edges of the V-shaped gap are joined by the edges being pressed by a pair of pressure rolls. In an electric resistance welded pipe manufacturing device that continuously performs electric welding with a shaft, by using an insulating material such as ceramic as a material, and by integrally providing shaft portions above and below a roll portion provided with an annular groove on the entire circumferential side portion of the cylinder, A pressure roll is formed, and the pair of pressure rolls are mounted at a predetermined interval in the roll case by supporting the shaft portion of the pressure roll, and the roll case is fixed on a stand. An electric resistance welded pipe manufacturing apparatus comprising an induction coil arranged at a position close to the pair of pressure rolls.