JP3263489B2 - Centering jig for pipe welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centering jig used for welding gas pipes, water pipes and the like.

[0002]

2. Description of the Related Art When welding pipes, it is essential that the pipes be welded in such a manner that the gap between the pipes is set to a predetermined size and the centering is accurately performed. .

[0003] For this reason, a welding operation is conventionally performed by a method shown in FIGS.

A. First, as shown in FIG. 4, the grooves of two pipes are butted, and a groove spacing adjusting jig A and a centering jig B are attached by welding so as to join the pipes. By the way, in the case of 32B pipe, A is attached at 4 places and B is attached at 16 places.

B. Next, as shown in FIG. 5, the nut A 'of the groove spacing adjusting jig A is rotated to adjust the spacing between the pipes to the set dimension.

C. Next, as shown in FIG. 6, the centering bolt B 'of the centering jig B is rotated to center the pipes.

D. Next, as shown in FIG. 7, after the pieces C are welded between the jigs A and B to temporarily connect the pipes, a groove dimension inspection is performed, and then the jigs A and B are removed.

E. Next, after performing the first welding, the piece C is removed, and the main welding is performed.

F. Next, as shown in FIG. 8, the welding traces D of the jigs A and B and the piece C are processed by a grinder E to finish it smoothly.

G. Next, as shown in FIG. 9, the periphery L including the welding line and the jig welding trace D is subjected to the penetrant inspection processing, and when the defect processing is found, the grinder E processing is performed again.

[0011]

However, the above welding method has the following disadvantages.

A. Jigs A and B as pipe diameter increases
, The work time for welding and grinder processing of the jigs A and B increases.

B. Since the number of temporary welding spots by the jigs A and B and the piece C increases, the probability that a defect is detected during the penetration inspection after welding increases, and the time required for the re-grinder processing and the inspection operation after the inspection increases.

C. The increase in the number of temporary welding points causes heat to be input to the groove of the pipe, which is not preferable in quality control. For this reason, reducing the number of temporary welding locations has been an issue.

An object of the present invention is to improve the above-mentioned problems a to c.

[0016]

The construction of a centering jig for pipe welding according to the present invention is as follows.

This is a jig for adjusting the groove of a pipe. The jig bodies 10, 10 'have a split shape which can be attached to one of the pipes so as to hold the pipe from above and below. Jig body 10,
At both ends of 10 ', fixing means 11, 11' which can removably connect and fix the split jig bodies 10, 10 'to each other are attached, and further, the jig bodies 10, 10' are further attached. the outer periphery of is projected fixed radially holder fixing plate 12 at regular intervals, further, the solid
The plate 12 has a front end extending horizontally and
A centering bolt holder 13 provided with a screw hole 16 in the extended tip in the vertical direction is detachably attached by a screw 14 , and further, a pipe hole of a pipe is provided in the screw hole 16 at the tip of the holder 13. A centering bolt 15 is attached so as to freely move in and out by the action of a screw 16 so as to face the center direction and to contact the outer peripheral surface of another pipe for centering the pipe to which the jig bodies 10 and 10 ′ are mounted. A centering jig for pipe welding.

[0018]

[Action] A groove of a pipe is abutted, and a groove gap adjusting jig is attached to the groove to adjust a gap dimension. This operation is the same as the conventional example. Next, the split jig body is vertically aligned with one of the grooves of the pipe, and both ends thereof are firmly fixed by fixing means, thereby being wound around the pipe. Next, centering is performed using the centering bolts of the jig body. Next, the pieces are welded and temporarily fixed, the groove dimensions are inspected, the first layer is welded, then the spacing adjustment jig and centering jig (jig body) are removed from the piping, and Perform grinder processing and penetrant inspection.

[0019]

1 to 3 show the structure of a centering jig according to the present invention.

Reference numerals 10 and 10 'denote jig bodies formed by dividing a circle into two parts. The jig bodies 10 and 10' can be fixed at both ends by fixing bolts 11 and 11 'as fixing means. Reference numeral 12 denotes a fixing plate radially attached to the outer peripheral surfaces of the jig bodies 10, 10 '. Reference numeral 13 denotes holders respectively attached to the fixing plate 12 by screws 14.
Reference numeral 5 denotes a centering bolt which is screwed into a screw hole 16 formed at the tip of the holder 13 so as to be able to move in and out toward the center of the pipe. Note that in FIG.
The illustration of the centering bolt 15 is partially omitted.

Next, an example of a welding operation performed using the above-described centering jig will be described.

The groove of the pipe is abutted, and a groove interval adjusting jig (the same as the conventional example) is attached to the groove to adjust the interval dimension. Next, the jig bodies 10 and 10 ′ are vertically aligned with one groove of the pipe, and both ends thereof are fixed with bolts 11.
11 'is firmly fixed, and centering is performed using the centering bolts 15 of the jig bodies 10, 10' (FIG. 3). Next, a piece (same as the conventional example) is welded and temporarily fixed, the groove dimensions are inspected, the first layer is welded, and then the gap adjusting jig and the jig bodies 10, 10 'are removed from the piping. After removal and main welding, grinder processing and penetrant inspection are performed.

[0023]

As described above, according to the present invention, the portion corresponding to the conventional centering jig B is formed by winding a jig body of a split shape from above and below on a pipe and fixing it with bolts so as not to directly weld to the pipe. did. As a result, the following effects are obtained.

A. Compared with the conventional welding method, the labor for directly welding or removing the centering jig B to / from the pipe, the grinder treatment of the welding trace, and the labor for the penetrant inspection can be saved. As a result, the work efficiency is improved, and the probability that a defect is detected by the penetrant inspection is significantly reduced.

B. Since the number of welding spots is reduced, adverse effects on the piping due to welding heat are reduced, and quality control can be sufficiently performed.

C. When the split jig body is formed of, for example, an aluminum band, the weight and weight of the jig body are reduced, so that the work and the transportation are facilitated.

[Brief description of the drawings]

FIG. 1 is a front view of a centering jig according to the present invention.

FIG. 2 is an explanatory view showing a part of a centering jig.

FIG. 3 is an explanatory diagram of an example of a centering operation.

FIG. 4 is an explanatory view of a jig used in a conventional welding operation.

FIG. 5 is an explanatory diagram of an example of adjusting a spacing between pipes.

FIG. 6 is an explanatory diagram of an example of centering of a pipe.

FIG. 7 is an explanatory view of an example in which a pipe is temporarily fixed with a piece.

FIG. 8 is an explanatory view showing a situation where pipes are welded and welding marks on a jig and a piece are subjected to a grinder process.

FIG. 9 is an explanatory diagram of a penetrant inspection range.

[Explanation of symbols]

 10, 10 'Jig body 11, 11' Fixing bolt 12 Fixing plate 13 Holder 14 Screw 15 Centering bolt 16 Screw hole

Continuation of the front page (56) References JP-A 54-46824 (JP, U) JP-A 57-52292 (JP, U) JP-A 54-67720 (JP, U) (58) Fields surveyed (Int) .Cl. ⁷ , DB name) B23K 37/053 B23K 9/028 F16L 13/02

Claims (1)

(57) [Claims] 1. A jig for adjusting a groove of a pipe, wherein the jig bodies 10, 10 'have a split shape which can be attached to one of the pipes so as to hold the pipe from above and below. With this jig body 1
At both ends of 0, 10 ', two jig bodies 10, 10
′ Are attached to each other so that they can be detachably connected to each other and fixed, and a holder fixing plate 12 is provided on the outer periphery of the jig bodies 10 and 10 ′.
There are projected fixed radially at regular intervals, further, before
Serial to the fixing plate 12 is detachably attached by a holder 13 screw 14 for centering bolt having a screw hole 16 toward the vertical direction to the extended tip with extending the front end side in the horizontal direction further, the screw hole 16 of the tip of the holder 13, directed to the center direction of the pipe, and to abut against the outer peripheral surface of the other pipe to perform centering with respect to the pipe, fitted with a jig main body 10, 10 ' Centering bolt 1
5. A centering jig for welding a pipe, wherein 5 is attached so as to be able to move in and out by the action of a screw 16.