JPS6130784Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a welded portion sealing device for an electric resistance welded pipe that isolates the welded portion and the high temperature area around it from the atmosphere during the manufacture of the electric resistance welded pipe.

Normally, an electric resistance welded pipe is made by passing a metal strip between a plurality of forming rolls and bending it from a U-shaped cross section to an O-shaped cross section with both ends facing each other to form a so-called open pipe. The tube is manufactured by passing the tube through a squeeze roll while slidingly contacting the contact tip, welding the heated opposite end to form a tube, and subjecting the tube to bead cutting and other finishing processes.

By the way, the opposite end of the open pipe is heated as it passes through the contact tip and moves toward the squeeze roll, and almost at the same time as it is heated to the welding temperature, it reaches between the squeeze rolls and the end of that side is welded. However, the temperature of the opposite end and the welded ERW pipe is extremely high before and after the point where the opposite end is welded (hereinafter referred to as the welding point), and the temperature of the opposite end and the ERW pipe after welding is extremely high. When exposed to the atmosphere, oxides are generated, which are trapped between the opposite ends and cause welding defects such as penetrators.

For this reason, sealing gas is usually injected into the high-temperature area as mentioned above to prevent contact with the atmosphere, but a large amount of flash is generated in this high-temperature area, especially near the welding point. Not only does the flash adhere to the above-mentioned seal gas outlet and clog it, but it also adheres to other peripheral equipment, causing frequent troubles such as deterioration of their functions.

Conventionally, methods have been adopted to blow away the flash using a sealing gas flow injected into the high-temperature region, a separate inert gas flow or water flow, or to cool and solidify the flash while it is floating. It is being However, these methods have drawbacks such as the inert gas flow or water flow conversely entraining the atmosphere, reducing the sealing function, and the water droplets coming into direct contact with the high temperature area, causing cold defects in the weld. It was hot.

In contrast, in Utility Application No. 55-95122, the applicant of the present application has sealed the outside of the pipe P and open pipe OP in order to seal the welding point of the ERW pipe and the high temperature area before and after it from the atmosphere, as shown in Figure 4. In addition to providing the gas blowing part 1', a seal cover 13' is brought into close contact with the outer peripheral surfaces of the pipe P and the open pipe OP in order to enhance the sealing effect.
A seal wall 2' that surrounds the high-temperature area inside the OP with an upstream wall 21' on the upstream side and side wall portions 22' on both sides, and a water supply pipe 5' that spouts water into the seal wall 2' are provided. However, the temperature is high in the area where the seal cover 13' is in contact with the outer peripheral surfaces of the pipe P and the open pipe OP because it is near the welding point, and current as electric resistance welding heat input flows. Therefore, a short circuit between the opposite ends E and E of the open pipe OP is not allowed, and the pipe P and the open pipe OP are continuously moving and always in a sliding state. Therefore, heat resistance, electrical insulation, and flexibility are required for the seal cover 13', and rubber plates, asbestos, and Teflon plates are used, but all of them have shortcomings in abrasion resistance and cannot be used continuously for long periods of time. It was difficult to do so.

The present invention was developed in view of the above circumstances, and its purpose is to provide a sealing gas outlet provided on the outside of the welding point and the high-temperature area before and after the welding point from the atmosphere, and to A gas curtain blowout section that blows out inert gas, etc. to form a gas curtain on both sides of the blowout section, a seal wall that surrounds the upstream side and both sides of the high temperature area inside the pipe and open pipe, and a seal wall that is surrounded by the seal wall. To provide a welded part sealing device for an electric resistance welded pipe, which is equipped with a nozzle for forming a water flow into an internal region, enhances a sealing function against a high-temperature region, and at the same time enables processing of flash without adhering to attached equipment. be.

The present invention will be specifically explained below based on the drawings showing its implementation. Fig. 1 is a perspective view showing the state of use of the welded part sealing device for electric resistance welded pipes (hereinafter referred to as the device) according to the present invention, Fig. 2 is a longitudinal sectional view, and Fig. 3 is a cross-sectional view taken along the - line in Fig. 2. It is a front view, and in the figure
OP is an open pipe, and is formed by passing a metal band through a plurality of forming rolls (not shown) and bending it from a U-shaped cross section to a roughly O-shaped cross section with both ends E, E facing each other. This open pipe OP has its opposing ends E, E in sliding contact with the contact tip C, and the opposing ends E, E which are heated by being passed between squeeze rolls SR and SR disposed on the downstream side. It is welded to form a pipe P, and is transported in the direction of the white arrow toward the finishing process. Then, the welding point O of the opposite ends E, E of the open pipe OP and the areas before and after the welding point O, that is, the opposite ends E, E and the opposite ends E, E that are in sliding contact with the contact tip C of the open pipe OP. The seal gas blowing part 1, the gas curtain blowing part 4, the seal wall 2, and the water supply pipe 3, which constitute the present device, are arranged facing a high temperature area such as the electric resistance welded pipe S in the welded pipe P. There is.

The seal gas blowing part 1 has a hollow rectangular box 11.
It is formed by a seal gas supply pipe 12 such as an inert gas or reducing gas, a partition plate 13, and the like. The box 11 is in the shape of a hollow rectangular parallelepiped, and its lower downstream side is partially closed off by a shielding plate 11b, but the upstream side thereof is an air outlet 11a, and its approximately central portion in the front-rear direction is closed off by a shielding plate 11b. The air outlet 11a is located above the welding point O, and the air outlet 11a is located in the high temperature area before and after the welding point O, that is, the upstream side is near the location where the contact tip C is disposed, and the downstream side is slightly further away from the center of the squeeze roll SR. They are fixed to a support frame (not shown) while facing each other while downstream. Note that the air outlet 11a provided in the lower wall of the box 11 may be formed as a slit hole or a large number of small holes instead of opening the entire surface. The tip of the seal gas supply pipe 12 is introduced into the box 11 through the upper wall of the box 11, that is, the ceiling, and extends parallel to the upper wall of the box 11 to the downstream wall, that is, near the front wall. A large number of blow-off ports 12a are formed in the peripheral wall facing the inner surface of the upper wall of the box 11, and the base end side of the seal gas supply pipe 12 is connected to a seal gas tank by interposing a flow rate control valve (not shown) in the middle. (not shown), and the seal gas is blown out from the outlet 12a of the seal gas supply pipe 12 toward the inner surface of the upper wall of the box 11.
box 1 while maintaining a predetermined static pressure state within box 1.
The air is blown out from the air outlet 11a in the lower wall of No. 1. A partition plate 13 attached to the lower end of the upstream side wall of the box 11 prevents seal gas from leaking to the upstream side, and prevents seal gas from leaking to the open pipe OP.
It is meant to guide you inside. Therefore, although it is desirable that the lower end of the partition plate 13 be as close as possible to the outer circumferential surface of the open pipe OP, it is not necessary that the two be in sliding contact.

The gas curtain blow-off section 4 includes a curtain gas supply pipe 41 that supplies curtain gas such as an inert gas, and curtain nozzles 42, 42. The curtain gas supply pipe 41 is connected to a curtain gas tank (not shown) with a flow rate control valve (not shown) interposed in the middle of its base end, and its end side is branched into two curtain nozzles 42, 42. The curtain nozzle 42,4
2 is a round pipe whose ends are sealed and has a slit-shaped outlet 42a formed therein, and is arranged horizontally along the outside of both side walls of the box 11.
It extends further downstream of the downstream wall of the box 11, and below that a plurality of slit-shaped air outlets 42a are formed toward the side wall of the box 11. From the curtain nozzles 42, 42, curtain gas is blown out along the outside of the box 11 as shown by the broken line arrow in FIG. It is designed to prevent air from being entrained. Note that the curtain nozzles 42, 42 are not limited to those having a slit-shaped outlet as described above, but may be those having a large number of minute holes as an outlet, or even a large number of gas nozzles each having one outlet formed therein may be arranged. good. In this way, the sealing gas blown out from the outlet 11a of the box 11 is not diffused on the way, and the gas curtain formed by the partition plate 13 and the gas curtain outlet 4 prevents atmospheric air from being drawn in from the outside. A part of the pipe can be guided into the open pipe OP between the opposing ends E and E, and the other part can be guided toward the open downstream side along the surface of the high temperature area. .

The seal wall 2 is made of a heat-resistant sponge or other appropriate elastic, heat-resistant, insulating, and water-tight material and is U-shaped in plan view. Slightly further upstream than the installation position, the lower ends of the side walls 22, 22 are fixed to the surface of the mandrel M so as to face both ends of the high temperature area, and the upper ends of the open pipe OP,
It is designed to come into sliding contact with the inner surface of the pipe P. The water supply pipe 3 has its distal end branched into a plurality of parts, each of which penetrates the upstream wall 21 of the seal wall 2 and is opened on the upstream side of the interior surrounded by the seal wall 2, and its proximal end is connected to the surface of the mandrel M. It is guided to the upstream side of the open pipe OP along the same line, led out to the outside through between the opposite ends E and E of the open pipe OP, and connected to a water tank via a pressure regulating valve and a pump (not shown). Water passes through the water supply pipe 3, is ejected from its tip side into the area surrounded by the seal wall 2, flows downstream along the surface of the mandrel M, is generated from the welding point O and its vicinity, and falls. The incoming flash is cooled and solidified, and is allowed to flow down into the pipe P as it is by a water stream.

In the device of the present invention constructed as described above, the seal gas blown into the box 11 from the seal gas supply pipe 12 in the seal gas blow-off section 1 is supplied to the box 1.
1, and is sprayed uniformly toward the outer peripheral surface of the high temperature area including the welding point O through the air outlet 11a on the upstream side of the installation position of the shield plate 11b, and the outer peripheral surface of the high temperature area while following the gas curtain formed by the gas curtain blowout part 4 while covering with a sealing gas atmosphere that does not contain oxygen.
It flows toward the downstream side which is in an open state, and the flash generated near the welding point O is discharged along the outer circumferential surface of the pipe P to the downstream side. Box 11
A shielding plate 1 that partially blocks the air outlet 11a is provided at the lower downstream end of the
1b prevents the sealing gas that has descended inside the box 11 from flowing out to the outside in a short-circuit manner, and is surrounded by the gas curtain formed by the partition plate 13 and the gas curtain blowout section 4. The sealing gas flows from the upstream side in the high temperature area to the downstream side along the outer circumferential surface of the high temperature area, and the utilization efficiency of the sealing gas is greatly improved. In addition, a part of the seal gas is passed between the opposite ends E and E of the open pipe OP that opens into the area surrounded by the partition plate 13 and the gas curtain formed by the gas curtain outlet 4, and is surrounded by the seal wall 2. The gas flows downstream into the area surrounded by the seal wall 2, while covering the inner circumference of the high temperature area with an oxygen-free sealing gas atmosphere along the outer circumference of the mandrel M and the inner circumference of the high temperature area. It flows toward the side, and guides the flash generated near the welding point O toward the surface side of the mandrel M and toward the downstream side. In the area surrounded by the seal wall 2, a water supply pipe 3 provided through the seal wall 2 is exposed on the upstream side, and the water spouted from the water supply pipe 3 is surrounded by the seal wall 2. Because it is designed to form a water current flowing from the upstream side to the downstream side,
The flash generated near the welding point O falls into the water flow, is cooled and solidified, and is also flowed out from the area surrounded by the seal wall 2 into the outside, that is, into the pipe P, and the flash is This does not cause any problems such as adhesion to the mandrel M or other equipment. In addition, since the water flow flows along the inner peripheral surface of the high temperature area, it is heated and water vapor or water droplets are generated from the surface of the water flow, but this water vapor and water droplets flow along the surface of the water flow from the upstream side to the downstream side. Since the sealing gas flow is directed toward the sealing gas, it does not come into direct contact with the inner circumferential surface of the high-temperature region, and cold defects and the like are reliably prevented from occurring.

Furthermore, the outer peripheral surface and the inner peripheral surface of the high temperature area are surrounded by a partition plate 13 and a gas curtain, respectively, except for the downstream side.
It is surrounded by a seal wall, and since the seal gas and water flow inside the seal wall, the seal gas flow and water flow do not involve the atmosphere, and the sealing function can be further enhanced. Since the tip of the water supply pipe is opened directly inside the area surrounded by the seal wall 2 to form a water flow, for example, a water tank is formed on the surface of the mandrel M facing the inner peripheral surface of the high temperature area. Compared to the conventional method, when the mandrel diameter is small in the water tank method, there are problems such as not being able to provide a sufficient depth of the water tank, but the device of the present invention does not have such problems.

In addition, since both sides of box 11 are isolated from the atmosphere by a gas curtain formed by a gas curtain outlet, the above-mentioned pipe P and open pipe OP
Unlike the case where the seal cover 13' is always in sliding contact with the seal cover 13', periodic replacement is not required, and it can withstand continuous use for a long period of time, making it practical.

In the above embodiment, only one seal gas blowing part 1 is provided on the outer peripheral surface of the high temperature region, but it may also be provided on the inner peripheral surface. However, in this case as well, it is desirable to adjust the blowing pressure of the sealing gas so that the sealing gas flows from the outer peripheral surface side to the inner peripheral surface side of the high temperature region.

As described above, in the present device, a water stream is formed on the mandrel surface facing the inner circumferential surface of the high temperature area including the welding point, and this water stream cools and solidifies the flash, and also causes it to flow out and be removed. This not only eliminates troubles such as the flash sticking to attached equipment, but also makes it extremely easy to dispose of the flash, as the flash is cooled and solidified and then removed from the high-temperature area by a stream of water. The present invention has excellent effects on improving the quality of ERW pipes.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the present device, FIG. 2 is a longitudinal cross-sectional view, FIG. 3 is a cross-sectional view taken along the line -- in FIG. 2, and FIG. 4 is a perspective view of the conventional device. OP...Open pipe, P...Pipe, SR...Squeeze roll, E, E...Opposite end, O...Welding point, 1...Seal gas outlet, 2...Seal wall, 3... Water supply pipe, 4... Gas curtain outlet,
11...Box, 12...Seal gas supply pipe,
13... Partition plate, 41... Curtain gas supply pipe.

Claims (1)

[Claim for Utility Model Registration] Electric resistance welding manufactured by welding the opposite ends of an open pipe, which is formed by bending the side ends of metal strips so that they face each other and applying pressure on both sides, by heating and applying pressure on both sides. A welded part sealing device for an ERW pipe that seals a high-temperature area before and after a welding point of the pipe, comprising: a sealing gas blowing part that injects sealing gas to the outer peripheral surface of the high-temperature area; and the sealing gas blowing part. a gas curtain blowout section that injects inert gas to form a gas curtain on both sides of the ERW pipe, and a mandrel inserted into the ERW tube through the open pipe to support a cutting tool for cutting an inner bead in the ERW section of the ERW tube. A seal wall is provided on the circumferential surface of the seal wall facing upstream and both sides of the high-temperature area, and a water flow forming nozzle is opened on the upstream side of the interior surrounded by the seal wall. Welded part sealing device for ERW pipes.