JPS59174285A - Electron beam welding method of large-sized structure - Google Patents

Abstract

PURPOSE:To assemble stably large-sized structures by electron beam welding with an inexpensive and small-sized installation by evacuating simultaneously the inside of the butted structures to a vacuum from both sides of a partition wall for shielding and evacuating further the inside of the structre side to be welded to a high vacuum. CONSTITUTION:The 2nd copper plate 22 is erected via a vacuum seal 23 on a surface plate 19, and the 1st body plate formed with an end plate 20 and a circumferential joint 39 is stucked and butted thereon. A backing strip 28 is welded to the outside circumference of a circumferential joint 40 and at the same time a partition wall 27 for shielding is attached by means of bolts and nuts 26 via sealing rubber 25 to a sealing plate supporting plate 24 attached on the inside circumferential surface of the 1st body plate 21 to segment airtightly the inside to the upper and lower parts. Rotary pumps 35, 38 and a diffusion pump 35 are then driven to evacuate the upper side of the wall 27 to a vacuum of about 1-10<-1>Torr and the lower side to a vacuum of about 10<-4>-10<-5>Torr. While an electron beam gun 32 is driven by a driving device 29 to rotate, an electron beam 33 is irradiated to weld the joint 40.

Description

[Detailed Description of the Invention] This invention relates to an electron beam welding method for large structures such as pressure vessels, and the present invention relates to an electron beam welding method for large structures such as pressure vessels. The purpose of the present invention is to prevent the evacuation equipment from increasing in size, and to manufacture the shielding partition from a thin plate to make it lightweight and inexpensive.

Generally, a pressure vessel as a large structure has a product diameter of approximately 4 mm.
Many of them reach a length of 30 to 40 m, and the manufacturing method is to sequentially butt weld a plurality of ring materials each having a length of about 4 m. However, since some of this type of ring material has a thickness of up to 250 mm, welding alone requires an extremely long time.

On the other hand, electron beam welding is suitable for welding thick plates as described above, and is capable of joining 250 mm thick steel in one pass, so it is considered to be extremely advantageous in terms of improving efficiency. However, the electron beam welding method is usually lQ To
Since it is necessary to carry out under a vacuum atmosphere of rr,
This poses a major obstacle when manufacturing large structures such as pressure vessels using electron beam welding. In other words, since this kind of large-sized pickles are huge in size and shape, a huge vacuum chamber is required to store them, and a portion of the circumferential joint of each ring material is stored in a vacuum chamber and electronically stored. Although it is possible to join by beam welding, since the product length of the pressure vessel ultimately reaches about 3 Q m, it is considered impossible to create a vacuum chamber to accommodate such a product.

Therefore, various techniques called local vacuum methods have been devised as methods for solving the above-mentioned problems. However, this type of local vacuum system has problems in stably maintaining the degree of vacuum, and has not yet been put to practical use in pressure vessels.

That is, the conventional electron beam welding method using the local vacuum method is configured as shown in FIG.
1) A cylindrical first structure (2) constituting a part of the pressure vessel is erected thereon, and a cylindrical second structure (3) is placed on the first structure (2). The two sides of the second structure (3) are hermetically closed by an end cover (4), and an arm is attached to the lower end of a support tube (5) fixed to the center of the end cover (4). (6) is rotatably supported, and an electron beam welding device (7) equipped with an electron gun or the like is attached to the tip of the arm (6).

Then, during welding, after applying an external seal (9) to the outside of the circumferential joint (8) of the both groove pickles (2) and (3), the both groove pickles (2) and (3) are passed through the exhaust pipe 00 of the base (1). 2) , (
3) is evacuated to a predetermined high vacuum, and the circumferential joint (8) is electron beam welded by the welding device (7) while rotating the arm (6).

In this way, this type of welding method uses the structures (2) and (3) that constitute the pressure vessel as they are as a vacuum vessel, and performs electron beam welding from inside the vessel. It has the advantage of not requiring a vacuum chamber to store it. However, the above-mentioned case has a serious drawback that it can only be applied to products of limited length, and the structure is the first. Second. Third. As the length of the container increases as the length of the container increases, the evacuation volume becomes enormous and it becomes difficult to maintain the required degree of vacuum.

Therefore, as a method to solve the above-mentioned problem, there is a method of always keeping the evacuation space constant.

That is, as shown in FIG. 2 and FIG. At the same time, the shielding partition (IJ is installed in the structure (1) adjacent to the structure (11)), and the structure (only the inside of the shielding partition α) is closed airtightly on the structure (16 side) using a vacuum device (not shown). is evacuated to high vacuum, and the electron gun Q supported by the electron gun drive system (14)
This is a method of electron beam welding the circumferential joint (16) of t (]υ from the inside. αη is the circumferential joint that has already been electron beam welded, and θ8) is a turnino roller.

In this way, by providing the shielding bulkhead (1 pier), the vacuum exhaust space can be limited to between the end seal Q-metal which sandwiches the circumferential joint 0O to be welded and the shielding bulkhead (1 pier). It is possible to solve the above-mentioned problems of maintaining the degree of vacuum and increasing the evacuation time due to the increase in product length.

However, in the case of the above method, only a limited space is evacuated to a high vacuum, so a pressure difference of about 1 atm occurs between the inside and outside of the shielding partition (1). is 1.5~''4m, so the pressure applied to the shielding bulkhead 0 east is a negligible value, that is, 20~125 tons.Therefore, the shielding bulkhead (13) must have a structure that can withstand this pressure. However, on the other hand, since the shielding bulkhead (13) will be moved from one installation position to another after welding is completed, it is desirable that it be lightweight from a work point of view. However, this type of shield bulkhead 0 East has the disadvantage of being expensive.

This invention was made with the above points in mind,
Two cylindrical first. A second structure is butted against the second structure, a shielding partition is attached inside the first structure, and a shielding partition is attached to the inside of the first structure.
．． The inside of the second structure is simultaneously evacuated from both sides of the shielding partition, the inside of the second structure is further evacuated to a high vacuum, and the joint is evacuated along the double-groove joint with an electron beam. by welding, another cylindrical third structure is butted against the end of the second structure, a shielding partition is attached inside the second structure, and the first, second... The inside of the third structure is simultaneously evacuated from both sides of the shielding partition wall, and the inside of the third structure is further evacuated to a high vacuum, and the inside of the third structure is evacuated to a high vacuum. The present invention provides an electron beam welding method for a large structure, characterized in that a joint of a third structure is electron beam welded, and a plurality of structures are subsequently electron beam welded in the same manner.

Therefore, according to the method for electron beam welding of large structures of the present invention, the interiors of multiple structures are simultaneously evacuated from both sides of the shielding partition, and the interiors of the structures to be welded are further evacuated to a high vacuum. Therefore, there is no significant pressure difference between both sides of the shielding bulkhead, and the shielding bulkhead does not need to be made of a thick plate that can withstand pressure of about 1 atm, and can be easily made from an inexpensive thin plate. In addition, the high vacuum evacuation space required for electron beam welding is not affected by the size of large structures, and the vacuum evacuation equipment does not have to be used. .

Next, this invention will be explained in detail with reference to the drawings from FIG. 4 onwards showing an embodiment thereof.

First, FIG. 4 showing one embodiment will be explained.

In the figure, 00 is a tea tray, (E) is a head plate that constitutes the end of the pressure vessel, (21) and @ is the first cylindrical structure that constitutes the body of the pressure vessel. The second body plate, (C) is a vacuum seal, (C) is a seal plate support plate, (C) is a seal rubber, 00 is a bolt, nut, (A) is a shielding partition made of a thin plate, the rut is a backing plate, (A) is a tea tray (1 drive device installed through the center of the samurai, (7) is supported by the drive device and rotated by the drive device (A), and has multiple exhaust holes 01 on the outer circumferential surface) HA is an electron beam welding gun supported by a rotating jig, which emits an electron beam (HA).

(2) is the first exhaust pipe that communicates with the exhaust hole 0υ of the rotating jig (7) via the drive device (a);
The 10th cryopump and diffusion pump connected to the exhaust pipe ■ (B) are the second exhaust pipe connected to the end plate (A), (
(To) is the 20th chest pump connected to the second exhaust pipe (G), 0! jl and θO are the circumferential joint between the end plate (A) and the first body plate 0υ, and the circumferential joint between both body plates Cυ, (A).

Next, the welding method of the above embodiment will be explained.

First, the first body plate (2) is erected on the tea tray (II) via a vacuum seal (C), and the end plate (A) connected to the 20th chest plate (C) is placed on the first body plate (Q1). pile up. Then, the inside of the first body plate 01) and the end plate (a) are evacuated to high vacuum using both rotary pumps (2), (c) and the diffusion pump (to) or only by the diffusion pump (g), and the drive unit (
While rotating and moving the welding gun 02 of the rotary jig (A) using (a), electron beam welding is performed around the circumferential joint g3. In this case, since the evacuation space is relatively small, the evacuation time is not much of a problem. "Next, pull up the mirror plate) and the first body plate (21), stand the second body plate (a) on the tea tray 0 [phase] via the vacuum seal (a), and then Stack the end plate (A) and the first body plate (1) on the body plate (A), and then stack the first and second body plates (0)
, match (a). At this time, a seal plate support plate (goods) is welded in advance to the inner circumferential surface of the first body plate 01), and the seal plate (c) is attached with the pole h and nut (c), and the end plate (a) and 1st.゛Second body plate @1) , (
The inside of c) is airtightly partitioned below by the shielding partition wall (a).

Then, after welding the backing plate (c) to the outer periphery of the circumferential joint (40) of both body plates Qυ, @, both rotary pumps (c),
Drive (c) to simultaneously evacuate the inside of the head plate (a) and both body plates Q1) and (a) from both the upper and lower sides of the shielding bulkhead (a), and maintain the vacuum at a low vacuum of about 1 to 10 Torr. do. Furthermore, the diffusion pump (c) is driven to evacuate the space below the shield partition wall (a), that is, the space on the second body plate (a) side where the circumferential joint θ0 to be electron beam welded exists, to a high vacuum. , maintained at a high vacuum of 10-1Q Torr. Thereafter, the welding gun C (circumferential joint θ0 by 2) is electron beam welded in the same manner as described above.

Furthermore, after the above-mentioned welding, the shield partition wall (a) is removed, and the third body plate (not shown) is erected on the tea tray 00, and the third body plate (not shown) is erected on the tea tray 00.
The mirror plate (a) and the 1st plate are placed on the 11ij plate. 2nd body plate 0υ.

(A) are stacked, and the shield partition wall (A) is placed on the seal plate support plate (not shown) on the inner circumference of the second body plate (A). The interior of the second body plate (2D, (A) and third body plate is simultaneously evacuated to a low vacuum from both sides of the shielding bulkhead (C), and the space on the third body plate side is evacuated using a diffusion pump (C). It is evacuated to a high vacuum, and the circumferential joint between the second shell plate (c) and the third shell plate is electron beam welded using a welding gun.

Similarly, the fourth. Fifth. Electron beam weld the body plate.

Therefore, according to the embodiment, the space on both the upper and lower sides of the shielding partition (c) is maintained at a low vacuum at the same time,
Since the space on the side where electron beam welding is to be performed is evacuated to a high vacuum, the pressure difference that occurs between both sides of the shielding partition Q; There is no need to construct a thick plate that can withstand a pressure difference of 1 atm, and it can be applied with an inexpensive thin plate, making it easy to handle, and the end plate (a) itself constitutes a part of the pressure vessel. Therefore, it can withstand pressure differences with atmospheric pressure.

Furthermore, the space on the side of the shielding bulkhead (a) where electron beam welding is to be performed can be maintained at a predetermined high vacuum using the diffusion pump (c), and even if the length of the pressure vessel becomes large, the space on the side where electron beam welding is to be performed can be maintained at a high vacuum. can be kept almost constant, so there is no major damage to the vacuum evacuation equipment, and as the pressure vessel increases, the head plate (
Although the space on the side (a) increases and the evacuation space increases, it is only necessary to maintain a low vacuum of about 1 to 10 Torr in the space, so the evacuation system will not be a big loss and will be cost effective. It can be made sufficiently practical, and the exhaust time will not be much of a problem.

Next, FIG. 5 showing another embodiment will be explained.

In the figure, the same symbols as above indicate the same things, and the difference from the above is that the electron beam welding gun Oj is connected to the circumferential joint c3! 'l
l, (moves along the outer periphery of 40. That is, as shown in the same figure, the first and second body plates Q)
), When electron beam welding the circumferential joint 00 of (a), the local vacuum chamber θ]) moves along the outer periphery of the circumferential joint tic).
Then, install a welding gun 06, evacuate the inside of the local vacuum chamber 0) to a high vacuum with the exhaust system θ pier, and electron beam weld the peripheral joint (4 [phase]. The space below the shielding partition wall (B) inside the container, which is connected to the 10th Tali pump (C) and the diffusion pump (G) via the first bleed pipe (B), This is an exhaust system that evacuates the space on the side where beam welding is to be performed, and in the above case, it is sufficient to maintain a vacuum sufficient to secure the outer welding pot in the space, so the maintained vacuum level is an order of magnitude lower, that is, 10 ~ 10 Torr is sufficient.

Therefore, both sides of the shielding partition wall (c) are simultaneously evacuated, and the space below the shielding partition wall (c) is evacuated to a higher vacuum, and electron beam welding is performed in this state, so it is the same as described above. effect can be obtained.

In addition, in the nQ section, the case where the pressure vessel is constructed by welding each body plate (21) and @ in an upright state has been explained, but the same applies when the pressure vessel is constructed horizontally as shown in Fig. 2 above. It is applicable.

[Brief explanation of the drawing]

FIG. 1 is a cut front view showing a conventional electron beam welding method for large structures, FIGS. 2 and 3 are cut front views and cut side views of other conventional methods, and FIGS. 4 and 5 are FIG. 3 is a cutaway front view of an embodiment of the electron beam welding method for a large structure according to the present invention. (21), (c)・1st. 2nd shell plate, (a) - shield bulkhead 0, Oi...electron beam welding gun, (40-circle joint. Agent: Patent attorney Ryuta Fujita)

Claims (1)

[Claims] ■ Two cylindrical first. the second structures are butted against each other, a shielding partition is attached inside the first structure, and the first. The inside of the second structure is simultaneously evacuated from both sides of the shielding partition wall, the inside of the second FR structure is further evacuated to a high vacuum, and the joints of the side structures are electron beam welded along the joints of the side structures. , another cylindrical third structure is butted against the end of the second structure, a shielding partition is attached inside the second structure, and the first, second...
Third. The inside of the li structure is simultaneously evacuated from both sides of the shielding partition wall, and the inside of the third structure is further evacuated to a high vacuum. A method for electron beam welding of a large structure, characterized in that a joint of a third structure is electron beam welded, and a plurality of structures are electron beam welded in the same manner as described above.