JPH03291167A - Jig for cladding by welding and cladding method by welding using same jig - Google Patents

Abstract

PURPOSE:To easily carry out cladding by welding, grinding and welding inspection by forming a jig main body of specified pieces of jig blocks extendable in the longitudinal direction. CONSTITUTION:The head 2 is inserted into a through hole 1a of the bottom of a pressure container 1 so that a jig block 6 faces the inside of the pressure container 1 and the upper end of the head 2 is positioned so that it is not projected from the lowest height part of a clad C and the head 2 is spot-welded partially and fixed on the through hole 1a. One or two pieces of jig blocks 5 are connected to the jig block 6 fixed on the jig erecting surface 2a of the head 2. Cladding by welding is carried out by MIG welding so as to surround the peripheries of the jig blocks 6 and 5 on the inside of the pressure container 1. When the welding surface 7a of a weld zone 7 attains the position slightly lower than the upper end which is made to a scale 3 of the jig blocks 5, grinding is carried out on the welding surface 7a and ultrasonic inspection is carried out. Afterward, a next jig block is extended on the jig blocks 5 and cladding by welding, grinding and ultrasonic inspection are carried out till the final set thickness is attained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an overlay welding jig used for overlay welding around a through-hole formed in a pressure vessel such as a nuclear reactor pressure vessel, and the jig. This relates to the overlay welding method used.

[Prior Art] Conventionally, as shown in FIG. 4, for example, when overlay welding is performed on the inner surface of a pressure vessel 1 so as to surround a through hole 1a formed in a reactor pressure vessel (pressure vessel) l. The overlay welding jig A has a jig standing surface 2a, which is one end surface of the cylindrical head 2, of a length corresponding to the final overlay welding height set in advance. In addition, a rod-shaped jig main body 4 having a scale 3 is fixedly erected on the circumferential surface 4a as a gauge part for determining the overlay welding height.

When overlay welding is performed using the overlay welding jig A, first insert the head #2 into the through hole la of the pressure vessel l so that the jig body 4 protrudes toward the inside of the pressure vessel l. After fitting and fixing, using scale 3 as a guide, overlay welding is performed on the inner surface of the pressure vessel i to a predetermined height so as to surround the circumferential surface 4a of the jig body 4, and then overlay welding is performed on the welded surface of the welded part 7. 7
A is grinded to make the welding surface 7a smooth, and then welding H7 is subjected to ultrasonic flaw detection from above the welding surface 7a using an ultrasonic flaw detection device (not shown), and then overlay welding is performed. The above-mentioned overlay welding, grinding, and ultrasonic flaw detection are repeated until the height reaches the final set thickness.

[Problems to be Solved by the Invention] By the way, as described above, the conventional overlay welding jig A has a jig standing surface 2a of the cylindrical head 2, and a peripheral surface 4a that serves as a guide for overlay welding. Since the rod-shaped jig main body 4 having a scale 3 is set up in a fixed state, if there are several welding locations with different final overlay welding heights, the length corresponding to each welding height is adjusted. Several types of overlay welding jigs A having the same size jig bodies 4 were required.

In addition, since the jig body 4 of the overlay welding jig A has a length corresponding to the final weld height of overlay welding set in advance, the jig body 4 of the overlay welding jig A has a length corresponding to the final overlay welding height set in advance. During grinder processing and ultrasonic flaw detection, the grinder or ultrasonic flaw detection device came into contact with the jig body 4, causing trouble in the work.

The present invention has been developed in view of the above circumstances, and can be used regardless of the final overlay welding height, and can also be used to perform grinding and ultrasonic flaw detection on the welding surface around the jig body without any problems. The object of the present invention is to provide a build-up welding jig and a build-up welding method using the jig.

[Means for Solving the Problems] The overlay welding jig of the present invention has a head that can be fitted and fixed into a through hole of a pressure vessel, and a head that is erected on one end surface of the head and that has a A jig for overlay welding is equipped with a rod-shaped jig body having a gauge part that serves as a guide for knowing the overlay welding height, and the jig body is divided into a plurality of parts with a predetermined length in the longitudinal direction, and the divided parts are It is composed of a plurality of jig blocks that can be added sequentially.

Further, in the overlay welding method using the overlay welding jig, the head of the overlay welding jig is placed in the through hole of the pressure vessel, and a jig block connected to the head protrudes into the inside of the pressure vessel. Insert and secure the jig block, surround the outer periphery of the jig block, and perform overlay welding on the inner surface of the pressure vessel so that the height is lower than the top surface of the jig block.This welding and the addition of the jig block are repeated alternately. In addition, grinding of the welding surface and welding inspection are performed at predetermined stages when overlay welding and jig block addition are performed alternately.

[Function] When performing overlay welding using the overlay welding jig of the present invention,
First, the head of an overlay welding jig is inserted and fixed into the through hole of the pressure vessel so that the jig block connected to the head protrudes into the pressure vessel.

Thereafter, overlay welding is performed on the inner surface of the pressure vessel so as to surround the outer periphery of the jig block and to have a height lower than the top surface of the jig block, and addition of the jig block is alternately performed.

Further, at a predetermined stage, grinding of the overlay welding surface and welding inspection are performed.

Furthermore, since the jig main body of the overlay welding jig is made up of a plurality of jig blocks that can be added to in the longitudinal direction, it can be used regardless of the final overlay welding height of the welding location.

In addition, the jig body is formed by sequentially adding the next jig block after welding inspection is performed for each build-up welding of a predetermined height, so the protrusion height from the welding surface is small, and therefore When performing grinder processing and welding inspection, the risk of the grinder or welding inspection device coming into contact with the jig body and interfering with the grinder processing and welding inspection is reduced.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In FIGS. 1 to 3, the same parts as shown in FIG. 4 are given the same reference numerals.

As shown in FIG. 1, the overall structure of the overlay welding jig A according to the embodiment of the present invention includes a cylindrical head that is fitted into a through hole la at the bottom of a pressure vessel l (see FIG. 2). 2, and a plurality of jig blocks 5 that can be erected on the jig standing surface 2a, which is one end surface of the head 2, and that are divided into predetermined lengths in the longitudinal direction.
It is equipped with a jig main body 4 which can be formed into a rod shape.

A cylindrical jig block 6 having a predetermined diameter and a predetermined length (for example, 20 mm in diameter and 10 sn in length) is integrally formed on the jig standing surface 2a of the head 2. An attachment recess 6b into which a protrusion 5a of a jig block 5, which will be described later, is fitted is formed in the tip surface 6a.

The jig block 5 has approximately the same diameter as the jig block 6 and approximately the same length as the jig block 6, and the mating surfaces of the jig blocks 6 and 5 and the mating surfaces of the jig blocks 5 and 5 are the second As shown in the figure and FIG. 3, it can be used as a scale (gauge part) 3.

In addition, each jig block 5 has a convex portion 5a formed on one end surface and a recessed portion 5b formed on the other end surface, as shown in FIG. The jig main body 4 is connected and formed by sequentially fitting the convex portions 5a of the jig blocks 5, the convex portions 5a of mutually adjacent jig blocks 5, and the concave portions 5b. Furthermore, the jig block 5 on the most extreme side is a T-shaped block when viewed in cross section and has no recess 5b formed therein.

In the figure, reference numeral 7 indicates a welded portion by overlay welding, 7a indicates a welding surface of the welded portion 7, and C indicates a cladding laminated on the inner circumferential surface of the pressure vessel 1.

Next, the welding method using the overlay welding jig shown in the embodiment of the present invention will be explained. First, as shown in Fig. 2,
After fitting the head 2 into the through hole la at the bottom of the pressure vessel l so that the jig block 6 faces inside the pressure vessel 1,
The upper end of the head 2 is positioned so as not to protrude upward from the lowest part of the cladding C, and the head 2 is partially fixed to the through hole 1a by spot welding.

After that, one or two jig blocks 5 are connected to the jig block 6 fixed to the jig standing surface 2a of the head 2.

At this time, the jig block 5 is added by fitting the protrusion 5a of the jig block 5 into the attachment recess 6b of the jig block 6 in the case of the jig block 5 closest to the base, and In the case of the jig block 5, this is done by sequentially fitting adjacent protrusions 5a and recesses 5b into each other.

After the jig block 5 is added to the jig block 6, overlay welding is performed on the inner surface of the pressure vessel l using a MIG welding device so as to surround the outer periphery of the jig block 6.5.

When the welding surface 7a of the welded part 7 that has been overlay welded reaches a position slightly below the upper end of the scale 3 of the jig block 5 shown in FIG. The welded surface 7a is made smooth by grinding, and then the welded portion 7 is subjected to an ultrasonic flaw detection inspection from above the welded surface 7a using an ultrasonic flaw detection inspection device (not shown).

After that, the next jig block is added to the top jig block 5 shown in Fig. 2, and overlay welding, grinding, etc.
Ultrasonic flaw detection is carried out according to the procedure described above, and as shown in Figure 3, the above-mentioned jig block addition, overlay welding, grinding, and ultrasonic flaw detection are carried out until the weld height reaches the final set thickness. Repeat.

When the welding height reaches the final thickness, the jig body 4 must be removed, but this is done by drilling holes in the area indicated by the imaginary line X in FIG. 3 using a machine tool. A tube will be inserted into the hole indicated by the imaginary line X and fixed in a later step.

As described above, since the jig main body 4 is constituted by a predetermined number of jig blocks 5 that can be connected in the longitudinal direction, it can be used regardless of the final welding height of the welding location.

In addition, since the jig body 4 is formed by successively adding the next jig block 5 after the ultrasonic flaw detection, the amount of protrusion of the jig body 4 from the welding surface 7a is small, and therefore the grinder to the welding surface 7a is During machining and ultrasonic flaw detection, the possibility that a grinder or an ultrasonic flaw detection/inspection device (not shown) will come into contact with the jig body 4 and interfere with the grinder machining and ultrasonic flaw detection is reduced.

Although the present invention has been described in detail above, the present invention is not limited to this embodiment, and even if there is a design change within the scope of the invention, it is included in the present invention.

For example, in the embodiments, pressure vessels to which the overlay welding jig and the overlay welding method using the jig of the present invention are applied include, for example, pressure vessels for heat exchangers in addition to nuclear reactor pressure vessels. , or other pressure vessels.

Further, the shape and length of the jig blocks and the connection structure of each jig block do not necessarily have to be limited to those shown in the embodiments, and the lengths of the jig blocks do not necessarily have to be the same length.

Furthermore, instead of using the scales provided on the circumferential surface of the jig block as connecting parts for each gauge block, new scales can be provided by, for example, inking or marking.

Furthermore, the height of overlay welding at each stage is not necessarily 20
The height does not have to be limited to mm, but may be any height that allows ultrasonic flaw detection.

[Effects of the Invention] In the overlay welding jig of the present invention, the jig main body is composed of a predetermined number of jig blocks that can be added to in the longitudinal direction, so it is easy to weld regardless of the final welding height of the welding location. The effect is that overlay welding, grinder processing, and welding inspection can be performed.

In addition, in the overlay welding method of the present invention, the jig main body is
After welding inspection is performed for each build-up weld of a predetermined height, the next jig block is added one after another, so the amount of protrusion of the jig block from the welding surface is small, making it easier to grind the welded surface. Also, during welding inspection, there is an effect that the risk of the grinder or welding inspection device coming into contact with the jig body and causing trouble in these operations is reduced.

[Brief explanation of the drawing]

Fig. 1 is an enlarged front view M including a partial cross section of the overlay welding jig according to the embodiment of the present invention, and Fig. 2 is an example of the overlay welding method using the overlay welding jig shown in Fig. 1. FIG. 3 is an enlarged vertical sectional view showing the overlay welding process in the step, FIG. 3 is a longitudinal sectional view showing the final overlay welding process in the overlay welding method of the present invention,
The figure is a longitudinal sectional view showing a conventional overlay welding method. In the figure, 1 is a pressure vessel, la is a through hole, 2 is a head, 2a is a jig standing surface (one end surface), 3 is a scale (gauge part), 4 is a jig body, 4a is a circumferential surface, 5 is a jig Block, 7 is welded part,
7a is a welding surface, and A is a jig for overlay welding.

Claims (1)

[Claims] 1) A rod-shaped jig that has a head that can be fitted and fixed into a through-hole of a pressure vessel, and a gauge part that is erected on one end of the head and that serves as a guide for knowing the overlay welding height on the circumferential surface. An overlay welding jig comprising a main body, wherein the jig main body is constituted by a plurality of jig blocks that are divided into a plurality of parts at a predetermined length in the longitudinal direction, and the divided parts can be successively joined. Welding jig. 2) Insert and fix the head of the overlay welding jig according to claim 1 into the through hole of the pressure vessel so that the jig block connected to the head protrudes inside the pressure vessel, and At a predetermined stage, the overlay welding applied to the inner surface of the pressure vessel and the addition of jig blocks are alternately repeated, and the overlay welding and addition of jig blocks are alternately performed to enclose the inner surface of the pressure vessel and the height is lower than the top surface of the jig block. An overlay welding method that involves grinding the weld surface and inspecting the weld.