JPH028624Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shielding device for a welded portion of a raw electric resistance welded steel pipe.

[Conventional technology]

ERW steel pipes are produced by forming a steel strip into a cylindrical blank pipe using forming rolls, heating the opposing seam edges using, for example, a high-frequency current via a contact tip, and then applying the heated seam edges to a squeeze roll. It is manufactured by press-welding.

As mentioned above, when the seam edge is heated and pressure welded with a squeeze roll, a shield device is used to maintain the welded area in a non-oxidizing atmosphere.

Conventionally, as a shielding means for a welded part of an ERW steel pipe, for example, Japanese Patent Laid-Open No. 53-119264, Japanese Patent Publication No.
A structure that covers the entire squeeze roll and contact tip portion as disclosed in Japanese Patent Publication No. 57-42427, or a structure that covers the entire squeeze roll and contact tip portion, or, for example, Japanese Utility Model Application Publication No. 56-23289.
A structure that covers only the heating part at the joint edge of the raw pipe as disclosed in Japanese Patent Publication No. 1983-26518, or a structure that covers only the heated part at the joint edge of the raw pipe as disclosed in Japanese Patent Publication No. 56-26518, for example. There are types that have a structure in which inert gas is sprayed onto the welded part.

[Problem that the invention attempts to solve]

By the way, among the conventional shielding means mentioned above, those that cover the entire squeeze roll and contact tip portion have large and complicated structures, so it takes a lot of time and effort to set up the shielding device, which reduces productivity. This causes a decrease in

Furthermore, in order to create a sealed structure for the shielding device, it is necessary to perfect the seals at many joints, which is difficult in practice and requires the use of large amounts of inert gas for shielding. Therefore, there are problems such as inert gas being undesirable in terms of cost and impact on the surrounding environment.

In addition, in the case of a product that covers only the heated part at the joint edge of the raw pipe, it receives heat from the melted part of the joint edge and has no choice but to come into contact with the high-temperature bead, so the seal has heat resistance and durability. Although a sealing member is necessary, it is very difficult to secure such a sealing member.

Furthermore, when inert gas is sprayed onto the welds at the joint edges of raw pipes, there is the problem that they are easily affected by turbulence in the surrounding airflow, making it difficult to obtain a stable non-oxidizing atmosphere. There is.

[Means for solving problems]

The present invention solves the problems of the conventional means described above, and its configuration will be explained below based on FIGS. 1 to 3.

As shown in FIGS. 1 to 3, cutouts 2a having similar cross-sections in half of the right and left squeeze rolls 1A are inserted into and included in the inner half of the upstream half of the squeeze rolls 1A on the left and right sides. A left and right side wall 2 in the section, a bottom wall 3 connected to the left and right side wall 2,
An upstream front wall 4 having a raw tube through hole 4a, an upper wall 5 having a welder insertion hole 5a on the upper surface, and a notch 2a in the left and right side walls 2,
A first shield box A is formed, which includes a seal member 6 made of, for example, rubber and installed over the upper surface of the inner half of the upstream half of each squeeze roll 1A, the roll hole-shaped groove, and the lower surface of the roll.

Next, a top wall 7 that encloses the upstream half of the upper squeeze roll 1B, and left and right side walls 8;
and a downstream rear wall 9 having a cutout 9a having a similar cross-section to the upper squeeze roll to expose the downstream half of the upper squeeze roll 1B;
and a second shield which is separably joined to the rear end surface of the upper half of the first shield box A via a sealing member 10 made of rubber, for example, and into which an inert gas is supplied by any means. Form box B.

[Effect]

Therefore, in advance, the first shield box A
are provided along the notches 2a of the left and right side walls 2 in the first shield box A by inserting the squeeze rolls 1A on the left and right sides from the entrance side so as to cover the inner half of the upstream half thereof. The sealed sealing member 6 is attached to the roll top surface of the inner half of the upstream half of each squeeze roll 1A, the roll hole type groove,
It is attached to the bottom of the roll.

Next, the second shield box B is fitted from the exit side of the upper squeeze roll 1B so that its upstream half is enclosed therein, and the downstream half is exposed from the notch 9a of the downstream rear wall 9. Insert,
In addition, the front end of the second shield box B is joined to the sealing member 10 surface on the rear end surface of the upper half of the first shield box A, and the first and second shield boxes A and B are connected to each other in a conventional manner (not shown). After that, the raw pipe P is connected by any connecting means that has been
In the first shield box A, a contact tip (not shown) is inserted into the roll hole mold of the squeeze roll 1A on the left and right sides through the seal member 6 from the raw tube through hole 4a of the upstream front wall 4. The high-frequency current passed through the tube heats the joint edge of the raw tube P on the inlet side of the squeeze roll 1A on the left and right sides, and inert gas is supplied into the second shield box B by an arbitrary means not shown. At the same time, the joint edges of the heated raw pipe P are pressed together by the squeeze rolls 1A on the left and right sides.

In addition, as shown in FIG. 4, the squeeze roll 1A at the position near the entrance side of the heating section of the joint edge part by the contact tip in the raw pipe P and the left and right side parts
Insert circular seal members 12 and 13 attached by a mandrel bar 11 into positions near the exit side of the
In addition, an inert gas is injected into the raw pipe P from an inert gas injection nozzle header 14 provided on the mandrel bar 11 between the circular seal members 12 and 13.

[Effect of idea]

According to the shield device of the present invention described above, the first shield box A can be inserted from the entry side of the squeeze roll 1A on the left and right sides so as to cover the inner half of the upstream half thereof. With,
Since the second shield box B can be inserted from the exit side of the upper squeeze roll 1B so as to enclose its upstream half, mounting of each shield box A and B is extremely easy, and the shield The work time for installing the device is shortened, contributing to improved productivity.

Moreover, the first shield box A and the seal member 1 on the rear end surface of the upper half of the first shield box A
A second shield box B is connected in contact with 0 and exposes only the downstream half of the upper squeeze roll 1B, and a blank pipe P passes through the roll holes of the squeeze roll 1A on the left and right sides. , since the inside of the second shield box B can be almost sealed, the inert gas supplied inside the second shield box B flows through the notch 9a of the rear wall 9 on the downstream side of the second shield box B. , is released only from the gap between the upper squeeze roll 1B and the inert gas consumption is small, so that a high level of non-oxidizing atmosphere can be maintained at the welded part of the raw pipe P.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the device of the present invention, FIG. 2 is a side view of the device of the present invention set in a squeeze roll stand, and FIG. 3 is a perspective view showing an embodiment of the device of the invention.
FIG. 4 is a sectional view showing a welded portion shielding means in the blank pipe. 1A...Squeeze roll on the left and right sides, 1B...
Upper squeeze roll, A...first shield box, 2...left and right side walls, 2a...squeeze roll half-section similar cutouts on left and right sides, 3...bottom wall, 4...front wall, 4a ...Main pipe through hole, 5...
Top wall, 5a... Welder insertion hole, 6... Seal member, B... Second shield box, 7...
Top wall, 8... Left and right side walls, 9... Rear wall, 9a...
...Cross-sectional similar cutout of the upper squeeze roll, 1
0... Seal member, P... Base pipe, 11... Mandrel bar, 12, 13... Circular seal member, 14
...Inert gas injection nozzle header.

Claims (1)

[Scope of utility model registration request] A left and right side wall 2 having a cutout 2a having a similar half cross-section of the right and left squeeze rolls in its downstream half into which the inner half of the upstream half of the left and right squeeze roll 1A is inserted and included, and the left and right sidewalls 2 , an upstream front wall 4 having a welder insertion hole 5a on the upper surface, a bottom wall 3 continuous to the base wall 3, an upper surface wall 5 having a welder insertion hole 5a on the upper surface, and the above-mentioned The first shield box A includes a sealing member 6 installed over the upper surface of the inner half of the upstream half of each squeeze roll 1A, the roll hole type groove, and the lower surface of the roll, and the upstream half of the upper squeeze roll 1B. the upper squeeze roll 1B; , and a second shield box B which is separably joined to the rear end surface of the upper half of the first shield box A via a seal member 10 and into which an inert gas is supplied. Shield device for welded parts of raw pipes.