JPS6242715B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a method and an apparatus for abutting large diameter steel pipes and pressing them together while heating them by induction heating.

One method of welding pipes is to press the pipes together while heating them. What is important in this butt welding of pipes is to accurately center the pipes to be welded and to be able to increase the upsetting pressure as much as possible. Not only does the roundness easily go out of order, there is a deviation in the outer diameter dimension, and the weight of the tube is large, so it is difficult to center it accurately. It is possible to improve the roundness of the pipe and eliminate deviations in the outer diameter dimension.Also, the necessary upsetting pressure was once thought to be 200 to 300 kg/ ^cm2 , but recently it has been reduced to It was found that a product of better quality could be obtained by doubling the amount or more.

In view of the above-mentioned circumstances, the present invention provides a method for easily and accurately centering large-diameter pipes, increasing upsetting pressure as much as possible, and obtaining a product of good quality when welding large-diameter pipes. This device was developed for the purpose of providing a device, which is arranged radially around one central axis on the inside of the tube, spanning the joint of the tube to be butt welded, and whose outer surface is radially arranged around one central axis. An interior member consisting of two groups of dowels each having a shape adapted to the inner surface of the pipe, always on the same circumference, and configured such that the diameter of the circumference can be enlarged or reduced, each of the dowels being arranged separately. Using a hydraulic device, screws, etc., the pipes are spread concentrically and fixed to the inside of both pipes, and at the same time, an exterior ring is fitted and tightened from the outside of the pipes so as to straddle the abutting portion of the two pipes. A main hydraulic cylinder placed concentrically with the central axis or on a circumferential surface concentric with the central axis is actuated to draw both pipes together and bring the pressure surfaces into close contact. After centering both pipes and making the abutting surfaces the same diameter, concentric, and round, the outer ring is loosened and separated from the abutting part to a position outside the abutting part of the interior member, and then The main feature is that an inductor is attached to the pipe to heat the part, and the main hydraulic cylinder is operated to press the two pipes together.

That is, in the present invention, when butt-welding the pipes, a stopper is extended from the inside of both pipes to the inner wall of each pipe, and even if the upsetting pressure is increased, the corresponding metal is sufficiently applied to prevent the above-mentioned stopper from slipping. In order to make it stick out strongly and maintain sufficient contact pressure there,
A ring is also fitted from the outside of the pipe to tighten the pipe from the inside and outside. It is effective in making the process easy and complete, and the effect is particularly great when the outer diameter of the tube is large. The reason for this is that the length of the tube remains the same but its diameter increases, so if you tighten both tubes from the outside with a ring that includes their abutting surfaces, and at the same time forcefully press both tubes together in the axial direction, it will be easier. This is because centering can be performed in a straight line, and the principle thereof will be explained with reference to FIG. 1 as follows.

Figure 1 is a diagram for explaining the above-mentioned principle, in which the butts 2 and 2' of the interior members of the pipes 1 and 1' to be butt-welded are pushed apart and fixed near the butt ends of the pipes 1 and 1', respectively. The pads 2 and 2' are pressed against the inner walls of the pipes 1 and 1' by the force of a hydraulic cylinder and pulled together, and the outer ring 3 that includes the abutting surfaces of the pipes 1 and 1' Apply it to the outer periphery of tubes 1 and 1 and tighten lightly to make the tubes perfectly round and at the same time correct the misalignment. Here, it is assumed that the core of the tube 1' is slightly inclined with respect to the tube 1, and a clearance C is generated at the abutting surface.

In order to perform centering until the clearance C disappears, it is sufficient to pull it strongly using the force P of the central hydraulic cylinder.

In this case, the weight of tube 1' is WKg, the outer diameter is Dcm,
Thickness is tcm, length is lcm, tensile force required for centering
If PcKg, Pc(D/2)=W(l/2) ∴Pc=l/D(D-t)πtωl However, ω is the specific weight of steel per ^1cm3 , 7.85×
10 ^-3 Kg, and on the other hand, if the upsetting pressure is Pu and its required unit pressure is σ _u , then Pu=σ _u (D-t)πt ∴Pc/Pu=l ² ω/ _Dσ uwhere, l=12m=1200cm, ω=7.85×10 ^-3
Kg/cm ³ , σ _u =500Kg/cm ³ , Pc/Pu=1200 ² ×7.85×10 ^−
3 /D×500=22.6/D.

That is, the larger the pipe outer diameter D becomes, the smaller the ratio of centering pressure to upsetting pressure becomes.For example, for a pipe with a diameter of 48B (D=121.92 cm), Pc/
Pu=0.19, and in a tube with a diameter of 56B (D=142.24 cm), Pc/Pu=0.16, so it is clear that centering can be done easily and accurately.

The method of the present invention applies the above-mentioned principle to easily and completely perform centering, and when upsetting the pipe, the outer ring used for centering is shifted to the position of the one stopper, and the outer ring is moved to the position of the other stopper. A ring is also fitted on the outside of the pipe to safely apply sufficient upsetting pressure for pressure welding, and by making the inner member short, it can be used even if there is a bend in the pipe. It was designed so that it could be easily removed after pressure welding.

Next, the structure of an apparatus for carrying out the method of the present invention will be explained with reference to the drawings, and the pressure welding process will be specifically explained.

Figures 2 to 4 show the winning amount 2 in Figure 1,
5 shows a device using a link as a means for opening and closing 2′, FIG. 5 shows a device using a wedge-shaped member in place of the link, and FIG. The structure of the reserve fund for this purpose is shown below.

In Figures 2 to 4, 1 is an existing pipe;
1' is a pipe to be pressed against the pipe 1; 2 is a plurality of metal fittings having an outer shape that closely fits the inner surface of the pipe 1 and arranged radially; and 3 is a metal fitting from the outside of the pipe 1 at the position of the metal fitting. Each of the fittings 2 has a bracket 201, into which a pin 4 is passed through and a ring 5 is pivotally attached, with the link 5 pointing toward the center of the tube 1 as shown in FIG. A bracket 701 is arranged radially and is provided radially around the boss 7 via a pin 6 at the end near the center of the tube.
and the length of the link 5 is tangent to the angle α between the link 5 and a plane perpendicular to the axis of the tube 1.
Choose so that α is around 1/4. In order to make the angle α adjustable, the structure of the support 2 may be as shown in FIG. 6, which will be described later. The boss 7 is fixed to the tip of the piston rod 9 of the main hydraulic cylinder 8 that generates upsetting pressure, and
A small hydraulic cylinder 10 is built in, and a boss 12 is provided at the tip of the piston rod 11 at right angles to the boss 12. A bracket 13 is arranged radially around the boss 12. is connected to a portion extending from the link 5 at an appropriate angle, thereby actuating the small cylinder 10 to move the link 5, opening and closing the stopper 2, and fixing or loosening the corresponding metal 2 on the pipe 1. It's becoming like that.

On the other hand, the ring 3 consists of half-split molds 301 and 302, which are connected at one end to be openable and closable by a pin 303, and at the other end to a pin 304 and a hook 305 that engages with the pin 304, and a hook 305 for tightening the hook 305. A hydraulic device (not shown) is provided to rotate the eccentric ring 306, and brackets 307 and 308 are provided on both sides of the pin 303, and after the hook 305 is released, the bracket 30 is
The ring 3 is designed to open naturally by passing the wire through the hole 7, 308 and pulling it upward in the direction of the arrow.
An actuator may be provided between the rings 08 and 08 to open and close the ring 3.

Further, 2' is a plurality of dowels having a shape that closely fits the inner surface of the tube 1' and arranged radially, and 3' is a ring 3.
It is a similar ring. Each of the bolts 2' has a bracket 201', through which a pin 4' passes, and a link 5' is pivotally attached thereto, and the link 5' is arranged radially toward the center of the tube 1'. The end near the center of the tube is connected to a bracket 801 provided radially around the main cylinder 8 via a pin 6', and the length of the link 5' is selected in the same manner as the link 5, and 10', 11', 12', 13',
14', 15', and 16' are the same as 10 to 16 described above.

17 is a plurality of guides fixed on the bracket 801 in parallel to the piston rod 9;
This is to allow the piston rod 9 to slide smoothly by guiding the boss 7 with these, and also to maintain substantially concentricity between the tubes 1 and 1'. To do this, first, it is necessary to attach the piston rod 9 to the pipe 1 while keeping it parallel to the pipe 1. As a method, a magnetic block 202 with an L-shaped cross section is fixed to the end face of the dowel 2 by magnetic force so that its key-shaped part touches the end face of the tube 1, and after determining the position of the dowel 2 and fixing it, Although the method of removing the magnetic block 202 is simple,
02 may be replaced by a key-shaped link so that it can be retracted after centering is completed.

An example of an apparatus for carrying out the method of the present invention is constructed as described above, and the press-welding process according to the present invention will be described below, with the rings 3 and 3' being referred to as the exterior ring and the other set as the interior member.

The exterior ring 3 and the stopper 2 of the interior member are attached to the appropriate positions on the end of the tube 1 so that they are tightened at the same position from the inside and outside of the tube 1. However, when tightening the interior member from the inside, Check that it is parallel to the pipe, and tighten by pulling the small cylinder 10. Next, the cylinder 8 is moved back, the stopper 2' is closed, the pipe 1' is fitted and brought into butt contact with the pipe 1, and then the outer ring 3' is inserted so as to include the abutting parts of the pipes 1 and 1'. After fitting and lightly tightening, cylinder 10'
Activate to push out the piston rod 11',
Push open the stopper 2' by the action of the links 14' and 5', support the tubes 1 and 1' substantially concentrically, shift the outer ring 3' to the position shown by the solid line as shown in Figure 3, and tighten it. At the same time, the cylinder 8 is operated to pull the pads 2 and 2' together and center them.

If each cylinder 10, 10' is left in operation in this state, even if the outer ring 3' is loosened, the center will not go out of alignment and there will be no misalignment, so the ring 3' can be Move it to the outside position of metal 2' and tighten it again to complete the preparation for pressure welding.

Note that centering is not limited to the above order, but may be performed in any appropriate order. If necessary, after centering once, readjust the liner that receives the pipe 1', and then It is also effective to loosen the tightening once and then tighten it again. Regardless of which procedure you follow, while tightening the abutting parts of the tubes 1 and 1' from the surroundings with the outer ring, the interior member will axially tighten the tubes due to their own weight. It is important to perform centering by applying a moment PcD/2 that is larger than the moment Wl/2, and to perform centering completely by pushing the stopper open until the end faces of both pipes are in perfect contact with each other without any misalignment. It is.

After completing the preparation for pressure welding as described above,
A split type inductor for heating the abutting portions of the tubes 1 and 1' is set and energized, and after the heating temperature is sufficiently raised, the hydraulic cylinder 8 is operated to perform pressure welding. Therefore, the upsetting allowance for pressure welding shall be limited to a predetermined amount by using a limit switch or by controlling the pressure.
In addition, depending on the application, the burrs caused by pressure welding should be cut off using a mechanical cutter, scarfing, gouging, etc., or only the apex of the bead should be ground with a sander until it becomes smooth. .

Although the present invention has been described above, the apparatus can also be implemented as shown in FIGS. 5 and 6.

That is, in FIG. 5, instead of the links 5 and 5' described above, wedges are used to push out or compress the pads 2 and 2', and the outer rings 3 and 3' are different from those described above. However, as interior members, 8 is a main cylinder, 9 is a main piston rod, 21 and 22 are guide frames, and on the outer periphery, guide surfaces 211 and 221 are respectively inclined at a certain angle with respect to the piston rod 9.
A plurality of small hydraulic cylinders 23, 24 are built in on the circumference concentric with the main cylinder 8, and the inner surfaces of the butts 2, 2' are brought into contact with the guide surfaces 211, 221 and supported slidably. It's summery. Discs 25 and 26 are attached to the tips of the piston rods of the small hydraulic cylinders 23 and 24 at right angles to the piston rod 9, respectively, and elongated holes 251 and 2 are formed radially.
Bolts 252, 262 fixed to the bolts 2, 2' are slid into the long holes 251, 261, and the bolts 2, 2' are moved back and forth by the operation of the cylinders 23, 24. The inclination of the guide surfaces 211, 221 opens and closes the butts 2, 2', and the degree of inclination of the guide surfaces 211, 221 is approximately the same as the angle of the link described above, and the guide surfaces are aligned with the piston rod 9. A suitable slope for the slope is around 1/4. Note that the same reference numerals as in FIGS. 2 to 4 indicate common parts.

In addition, in FIG. 6, the stop is divided into two parts 2 and 202 by a step-like surface, the slope of the step is in the same direction as the guide surface 211, and the engagement position of the two blocks is adjusted as appropriate. They are fixed to each other with bolts 203, and the rest of the structure is the same as that shown in FIG. By configuring the stopper as described above, it is possible to make very fine adjustments and there is no risk of the seam slipping even under upsetting pressure. You can also exchange it for something. In this figure, only one of the winnings is shown, but it goes without saying that the other winnings 2' may be constructed in the same manner.

Normally, a hanging hole 802 is provided in the main cylinder 8, through which a wire is passed, and after the pressure welding is completed, the interior member is pulled out using this rope, and then set again at the next pressure welding position or taken out. .

Further, the structure of the interior member and exterior ring in the present invention is not limited to the above example, and it is also possible to interpose screws, gears, etc., and use a hydraulic motor instead of the cylinder.

Furthermore, in the above example, there is one main hydraulic cylinder 8 in the center, but
It is also possible to arrange concentric cylinders every other bet between the winnings. This is shown in FIG. 7 below.

That is, in FIG. 7, 1, 1', 2, 2'3,
3' is the same as described above, and 171 is a guide made of a cylinder concentric with one central axis, replacing the four guides 17 protruding from one main hydraulic cylinder 8 in the previous example, and the main cylinder 34 and cash 2,
2' are alternately attached to the outer periphery and guided. 27, 27' are wedges that are combined with the butts 2, 2', and are attached to the flanged sleeve 2.
8, 28' and in the direction of the central axis x-x of the tubes 1, 1' and the guide 171.
The screws 29, 29' are configured to be movable by the rotation of the pinions 29, 29', thereby opening and closing the pads 2, 2'.
It is driven by a motor 33 via gears 31, 31' and pinions 32, 32'. Further, the dovetail grooves are cut on the long end faces of the dowels 2, 2', and are fitted into protrusions provided radially on the flange surfaces of the sleeves 28, 28'. On the other hand, the gears 31, 31' can only be moved in the radial direction without moving in the axial direction.
rotates using sleeves 28, 28' as bearings,
Screw 2 so that each stop opens and closes concentrically.
This is to synchronize the rotations of 9 and 29'. A block 35 is fixed to the sleeve 28, and this block 35 is fixed to the tip of the piston rod of the main hydraulic cylinder 34, thereby connecting the main hydraulic cylinder 34 and the sleeve 28.

Above 2, 27, 28, 29, 30, 31, 3
2, 33, 34 constitute one interior member and are fitted so as to be able to slide on the guide 171, while 2', 27', 28', 29', 3
0', 31', 32', 33', and 35 constitute another interior member, and as mentioned above, 34 is the main hydraulic cylinder, and the sleeve 28' is the main hydraulic cylinder.
It is fixed at 71.

Therefore, in the devices shown in FIGS. 2 to 5 and the device shown in FIG.
They are common in that they are arranged coaxially with the central axis of the book, and that the guide and the main hydraulic cylinder are fixed to each other, and the interior parts can be moved along the guide by the movement of the piston rod. The structure of the interior member is equivalent to that of the previous example, and the pinion 3 used in the above
0, 30', gear 31, 31', pinion 32, 3
A chain and sprocket may be used in place of 2'.

The present invention is as described above, and the interior members for butt pressure welding that have been proposed in the past are constructed to be strong and long so that centering of the pipe can be done in one step, so they are heavy in weight. It is unsuitable for butt pressure welding of large diameter pipes, and if the pipe has a bend, it cannot pass through that part, so it is also unsuitable for butt pressure welding of pipes with bends. On the other hand, according to the method of the present invention, the device is short and light weight, and even if the pipe has a bend, it can pass through the bend, so it is possible to butt pressure weld pipes with bends. By tightening the pipe from the inside and outside, centering and misalignment can be made more accurately, and an extremely large pressure can be applied, which has the advantage of improving the performance of the joint.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the principle of the present invention, Fig. 2 is a longitudinal sectional front view showing the state in which the device of the present invention is mounted on a pipe and the two pipes are butted together, and Fig. 3 is a state in which pressure welding preparations have been completed. Fig. 4 is an enlarged longitudinal side view of Fig. 3, Fig. 5 is a longitudinal front view of a state in which a different interior member is used and the pipe is centered, Fig. 6
The figure is an enlarged longitudinal sectional front view showing a part of another example of the interior member shown in Fig. 5, FIG. The figure is a right side view of FIG. 7. 1,1'...tube, 2,2'...money, 3,3'...
...Exterior ring, 4,4'...Pin, 5,5'...Link, 6,6'...Pin, 7...Boss, 8...Main hydraulic cylinder, 9...Piston rod, 10,1
0'...Small hydraulic cylinder, 11,11'...Piston rod, 12,12'...Boss, 13,13'...
...Bracket, 14, 14', 15, 15'...Pin, 16, 16'...Link, 17,171...
Guide, 21, 22... Guide frame, 23, 24...
Small hydraulic cylinder, 25, 26...Disc, 27, 2
7'... Wedge, 28, 28'... Sleeve, 29, 2
9'...Screw, 30, 30', 32, 32'...Pinion, 31, 31'...Gear, 33...Motor, 34...Main hydraulic cylinder.

Claims (1)

[Scope of Claims] 1. Disposed radially around one central axis on the inside of the pipe, spanning the joint of the pipe to be butt welded, and whose outer surface is always the same in shape and conforms to the inner surface of the pipe. An interior member consisting of two groups of dowels arranged on the circumference and configured to be able to expand and reduce the diameter of the circumference is formed into concentric circles using hydraulic devices, screws, etc. installed on each dowel. 1, which is spread out and fixed to the inside of both tubes, and at the same time, an exterior ring is fitted and tightened from the outside of the tube so as to straddle the abutting portion of both tubes, and is arranged concentrically with the central axis of the one tube. The main hydraulic cylinder installed on the circumferential surface concentric with the central axis is operated to pull both pipes together and bring the pressure surfaces into close contact, thereby aligning and bringing the pipes into contact. After making the surfaces the same diameter, concentric, and round, the exterior ring is loosened to separate the abutting part from the abutting part of the interior member to the outside position, and then an inductor is installed to close the part. A method for butt-welding large-diameter pipes, the method comprising heating and operating the main hydraulic cylinder to press-weld both pipes. 2 The scope of the patent claims that there are two exterior rings, one of them is used for centering the pipe, and for pressure welding, each of the exterior rings is exteriorized at the positions of both butts of the interior member, and the pipe is tightened from the inside and outside. The pressure welding method described in item 1. 3. Fit the first stopper of the interior member and the first outer ring into proper positions near the end face of the first pipe, and tighten and fix the pipe from the inside and outside, while slightly tightening the second stopper. Using this as a guide, insert the second tube until its end surface contacts the end surface of the first tube, and then fit the second outer ring so that it includes the abutting parts of both tubes. At the same time as tightening, centering is performed by strongly pushing open the second stopper and operating the main hydraulic cylinder to bring the contact surfaces of both pipes into close contact.If necessary, repeat the above operation to perform centering. 3. The pressure welding method according to claim 1, wherein after the pressure welding is completed, the second outer ring is loosened, shifted to the position of the second abutment, and then tightened. 4 A main hydraulic cylinder, a plurality of brackets fixed radially around the cylinder, links connected to the brackets with pins, each of the links connected to the tip with a pin, and the outside of the cylinder is in close contact with the inner surface of the pipe. a boss fixed to the tip of the piston rod of the main hydraulic cylinder and having a plurality of brackets radially around the circumference, a link connected to the bracket with a pin, and a boss connected to the tip of the link with a pin and whose outer side is The outer surface of each stop is the same, and the outer surface of each stop is the same.The outer surface of each stop is the same. A small cylinder that is driven to be on the circumference, a link that is connected to the small cylinder and an extension of the link that supports the abutment, and a boss that is fixed to the front surface of the main hydraulic cylinder and that is at the tip of the piston rod. 1. A butt pressure welding device for large diameter pipes, comprising an interior member comprising a guide for guiding the pipe, and an exterior ring that tightens the pipe from the outer periphery of the pipe at a position where the interior member contacts the inside of the pipe. 5. A main hydraulic cylinder, a guide frame that is fixed to the cylinder, contains a plurality of small cylinders on a circumference concentric with the cylinder, and has a plurality of guide surfaces each inclined at a certain angle with respect to the piston rod on the outside thereof. , a stop that abuts and is slidably supported on each of the inclined surfaces of the guide frame and that can come into close contact with the inner surface of the pipe on the opposite side; a stop that is fixed to the tip of the piston rod of the main hydraulic cylinder and is concentric with the piston rod; a second guide frame that includes a plurality of small cylinders on the circumference thereof and has a plurality of guide surfaces inclined at a constant angle on the outside thereof;
A stop that abuts and is slidably supported on each of the inclined surfaces of the guide frame and that can come into close contact with the inner surface of the pipe on the opposite side, and a main hydraulic cylinder is connected to the main hydraulic cylinder via a piston rod of a small cylinder built in both guide frames. a disc held concentrically with the piston rod, bolts that slide into elongated holes provided radially in the disc and are fixed to the respective bolts, and a tip of the piston rod of the cylinder that is fixed to the front surface of the main hydraulic cylinder. 1. A butt pressure welding device for large diameter pipes, comprising: an interior member comprising a guide for guiding a boss provided in the pipe; and an exterior ring that tightens the pipe from the outer periphery of the pipe at a position where the interior member contacts the inside of the pipe. 6. Claim No. 6, in which the stopper is divided into two parts by a step-like surface, and the outer diameter of the interior member can be adjusted by the combination of the steps, and the outer stopper can be replaced if necessary. The pressure welding device according to item 4 or 5. 7 A guide consisting of a cylinder concentric with one central axis,
a flanged sleeve loosely fitted into the guide; a flanged sleeve fitted and fixed onto the guide opposite the sleeve; and a flanged sleeve disposed radially at regular intervals between the sleeves and parallel to the central axis. A stop whose outer surface is in close contact with the inner surface of the pipe via a slidable wedge, a main hydraulic cylinder that connects both sleeves between the ends, and a main hydraulic cylinder that opens and closes the stop by sliding the wedge. 1. A butt pressure welding device for large diameter pipes, comprising: an interior member comprising a driving device for the interior of the pipe; and an exterior ring that tightens the pipe from the outer periphery of the pipe at a position where the interior member contacts the inside of the pipe.