Method of making molds-refrigerator-electrical power supply to the unit flash butt welding

 

The invention relates to nuclear energy and may find application in the manufacture of fuel elements of the assemblies of nuclear power reactors during sealing. Cut a workpiece in the form of plates of sheet bronze. Made washers stiffness and ring current supply of bronze with polishing the same plane. Assemble the jig. Mark washers stiffness and ring electrical power supply. Perform the Central hole and the holes for mounting, cut threads in the holes for the fastener and the washer hardness. Disassemble the package, labeled plates of bronze. Carry out degreasing, thermal oxidation of the workpieces strips of steel and plates of bronze to form a stable homogeneous color of the oxide film and the preliminary Assembly. Placed on the polished surface of the ring busbar on top of the washer hardness and compress with exposure time. Fix package with screws. Fill in the gaps between the screws and the package with a mixture of epoxy resin with hardener. Install insulators and conduct final plate package, extract compressed, the processing of the external surface of the package in the specified size, cutting package on three sectors according to the number of petals is e with the formation of the mold-refrigerator-electrical power supply. This increases the yield of fuel elements by improving the quality of their welds and the life of the mold-refrigerator-electrical power supply. 8 C.p. f-crystals, 6 ill.

The invention relates to nuclear energy and may find application in sealing fuel elements.

The main requirement of fuel elements (Cartridges), representing a zirconium tube, preformed curb nuclear fuel and sealed in a helium atmosphere, is the tightness of welded joints, sealing caps to the shell with two ends, and resistance to corrosion.

Currently, a large part of fuel Rods for nuclear power plants (NPP) is made by electron beam welding stub to the zirconium sheath and after equipment preformed nuclear fuel and install the clamps in the open end of zirconium shell sealing the other end of flash butt welding stub to the shell under the pressure of the inert gas inside the shell.

The famous “canadian” way of the contact-butt welding is used to seal the fuel Rods “CANDU”, in which the shell Fuel use for which the two elements of equal thickness was - shell and plugs.

By passing current pulse metal in the contact zone is instantly heated to temperatures close to the solidus. In this moment there is sediment welded elements with the formation of burrs of metal displaced from the zone of the joint deformation in both sides of the seam, requiring its removal by mechanical methods (see Development, production and operation of fuel cell power reactors. Book 2. Edited by F. G. Reshetnikov. - M.: Energoatomizdat, 1995, pages 217-218, Fig. 20.16).

The mold-refrigerator-electrical power supply (PCTs) in the known Assembly is detachable clamping device.

The disadvantages of “canadian” method as follows:

1. the need for the use of detachable clamping devices, which affects the alignment of the welded elements and makes the development of a fully automated lines;

2. the presence of burrs, precluding the use of continuous Tsang and the possibility of extraction of the welding device sealed fuel rod by simply moving it along the axis. You want to remove the Burr by machining both ends of the fuel rod, using a rotating tool or rotate the loaded fuel rod, which is undesirable;

3. the length is not enough (see ibid, page 219).

The second method of flash butt welding, called KCC-2, developed in Russia. Unlike the previous method, the formation of the welded connection at KCC-2 is made in conditions of all-round compression zone of the welding ring mandrel (see ibid., rice, 20.17, pp. 218-219).

For welding use a stub of reduced diameter compared to the outer diameter of the sealing membrane, and the external flash does not go beyond the dimensions of the outer diameter of the shell.

The mold-refrigerator-electrical power supply in the known Assembly is a ring mandrel.

As in “canadian” way and the “Russian” way as the mold-refrigerator-electrical power supply used in the first case, the detachable clamping device, and the second ring mandrel. When the clamp fuel element in a detachable clamping device or in a ring mandrel, the thickness of the shell can be considered as the total thickness of the shell and a detachable clamping device and as the total thickness of the shell and the ring mandrel.

However, due to the increase of the current shunting through the collet clamp (clamping device or ring mandrel) heating of the shell decreases, the heating zone above the temperature which the transfer membrane in butt plugs, that is unacceptable from the viewpoint of the corrosion resistance of the welded connection. The welded joint obtained in solid collet clamp (clamping device or ring mandrel), is limited to not more than 1.5 S, where S is the thickness of the shell. Margin of safety connections and corrosion resistance of such compounds are low. The reason is that the electrical resistance of the collet clamp clamping device or ring mandrel lower than the resistance of the shell.

As a result, the area of the shell is not fully warmed, which limits the depth of crimp plugs by an amount equal to the thickness of the shell, i.e. the length of the connection - 1.5 S, where S is the thickness of the shell.

An object of the invention is to increase the yield of fuel elements, reliability of welded joints and increase the service life of the device in the form of the mold-refrigerator-electrical power supply.

The technical problem is solved by the method of manufacturing the mold-refrigerator-electrical power supply to the unit flash butt welding includes cutting blanks strips of steel sheet with thickness of 0.02 to 0.05 mm, the cutting of workpieces in the form of plates of sheet bronze with a thickness of 0,3...0,5 mm, manufacturer of washers of gastrostomy, Assembly washer hardness, blanks strips of steel, billet plates of bronze in an alternating and ring current supply to the conductor, marking washers stiffness and ring electrical power supply on the same line, a Central hole and the holes for the fasteners, tapping the holes for the fastener and the washer hardness, disassembly of the package marking plates of bronze, degreasing, thermal oxidation of the workpieces strips of steel and plates of bronze to form a stable homogeneous color of the oxide film, the implementation of pre-Assembly, when the ring busbar collect the package in accordance with the marking in alternating sequence in the form of a billet plate of bronze, then billet steel plate, placing on the polished surface of the ring busbar on top of the washer hardness polished surface inside the package and compress with exposure time, the consolidation package screws, fill the gaps between the screws and the package with a mixture of epoxy resin with hardener, installation of insulators and the final screed package screws, self-control in compressed state, the processing of the external surface of the package in the specified size, cutting paketiku, the consolidation of the sectors of the package in a three-Tsang with the formation of the mold-refrigerator-electrical power supply, compression and tightening the mounting screws until snug.

The problem is solved also by the fact that the material of the gaskets used steel NEGAST 10994-74, blank plates use bronze Brhtsr THE 48-21-5050-82 with hardness not less than 110 HB for washer stiffness and ring busbar use bronze Br.NTBs THAT 48-21-92-72, thermal oxidation billet spacers is carried out at a temperature of 600...650With over 10...15 minutes

Obtaining an insulating gaskets thermal oxidation of plates of bronze is carried out at a temperature of 600...650With over 35...40 sec, compression package carried out with a force of 5000 5100...kgf aged for 5...6 min exposure at a final screed exercise 74 72...hours at a temperature of 20...21With, compression molds-refrigerator-electrical power supply in the collet carried out with a force of 2500...2600 kgf.

Accommodation on the inner side of a three collets and enshrines the mold-refrigerator-electrical power supply, made divided by the number of petals collet clamp that combines the mold, refrigerator (tool retraction delirously steel spacers between them, fixed with screws, isolated from bronze plates and insulating the mold-refrigerator-feeding insulators and epoxy resin, the formation of the weld metal in terms of volume compression at high specific pressures, short cycle welding and intense heat from the outer layers of the heating zone in combination with the ability to process in the solid phase, i.e., without melting the metal to be welded shell and insert allows you to get:

- small (at the level of maximum size in the base metal) grains in the zone of the bead,

- minimal in comparison with other methods of welding heat-affected zone;

- high metallic continuity of the weld metal (absence of defects);

- high strength weld metal and compounds in General;

- high corrosion resistance of connection due to the persistence of its outer layers including, in the most dangerous section is at the junction of the fuel cladding to the end of the stub of the original structure of the parent metal. This is because mold-refrigerator-feeding performs the following functions: prevents rastorgovka the end of the membrane surfaces into it during welding of the work pieces clamped the mold-refrigerator-electrical power supply; prevents the output of the outer Burr beyond the outer diameter of the fuel cladding; provides the ability to create conditions volumetric compression of the weld metal in the process of forming a welded joint; leads to shell welding current; removes heat from the fuel cladding in the weld zone, preventing heat it above its recrystallization temperature and thereby maintaining the original structure of the metal fuel cladding, i.e. zirconium; provides a specified mode of the temperature field in the fuel cladding, which increases the reliability of sealing and the yield of fuel elements. The heat and set the mode of the temperature field is provided by alternating oxidized bronze plates and insulating steel spacers between them with high electric resistance.

In addition, insulating steel strip attach the mold to the refrigerator to the electrical power supply rigidity and prevent deformation of the mold-refrigerator-electrical power supply during repeated compression collet clamp, which increases the yield of fuel elements and increase the service life of the mold-refrigerator-electrical power supply.

With the ECC-form-refrigerator-electrical power supply;

in Fig.3 - position shell and plugs at the beginning of welding;

in Fig.4 - the final moment of welding shell cover;

in Fig.5 is a manufacturing process flow of the mold-refrigerator-electrical power supply;

in Fig.6 - drawer blank.

The unit flash butt welding of fuel elements automatic line their production contains at least two settings for flash butt welding of fuel elements, each of which includes a movable welding chamber made perpendicular to the axis of the connector 1, separating the working cavity into two parts 2, 3, installed on the frame with the possibility of Autonomous reciprocating movement, provided with a through axial channels 4, 5 by means of 6 create suction and supply of neutral gas from the cylinder 7, the device 8 filing preformed curb nuclear fuel shell 9 of the fuel element, the device 10 of the feed stub 11 in the working cavity and the mechanisms of their capture in the form of a three-Tsang 12 for shell and collet clamp 13 for plugs with tubular rods 14 and 15, arranged in end-to-end channels and connecting the collet 12, 13 with the appropriate actuators 16, 17 mounted on the actuator 17 of the tubular rods with the possibility of joint movement. The source 19 of the welding current is connected to the ring busbar 20, combined with the mold 21 and the tool 22 of the heat from the welding point, forming the mold-refrigerator-feeding.

Each three-collet 12 to the shell 9 is provided on the outer side of the removable metal with polished inner surface of the sleeve 23 with a hardness higher than the hardness of the mating surface of a three-Tsang angle of the inner cone, is equal to the response, the corner of a three-Tsang 12 forming one half of the welding chamber, the inner cavity of which is placed a removable mold-refrigerator-current lead 24, is cut by sector 25 the number of petals of a three-gripper 12, combines the mold 21, the tool 22 of the heat from the welding point (fridge) and current lead 20 to be welded preformed curb nuclear fuel 26 with tabs 27 of the sheath 9 made of washers 28 stiffness and alternating plates 29 bronze with oxidized surface as insulators from each other and an insulating oxidized steel strips 30 which are orthogonal to the parting of the mold-refrigerator-electrical power supply 24, is fixed by screws 31, isolated from bronze Sidney resin.

Channel 6 each of the welding chamber, communicating with the means for creating suction and supply of neutral gas made in the wall of the tubular traction in parts 2 to 33 forming the welding chamber.

Each device 10 supply plugs 11 in the chamber of the welding unit flash butt welding is made of are installed on a common base with the vibrator 34 two vibrates 35 separate supply plugs 11 through the trays 36 in inclined chute 37 with photosensors 38 and the selectors 39 single-piece feed in a horizontal cradle 40, each of which is supplied by the pneumatic cylinder 42 horizontal feed stub 11 in the Chuck 13 and the pneumatic cylinder 43 input lodgement 40 with the cap 11 in the chamber of welding 1 and the output of the lodgement of the chamber welding.

The device 8 to supply fuel cladding 9 made in the form of roller conveyors with reverse engines with roller clamps 44 and pneumatic clamps 45. Means 6 create suction and supply of neutral gas from the cylinder 7 with the pipe 46 provided with a vacuum system (not shown).

Making molds-refrigerator-electrical power supply to the unit flash butt welding is as follows.

Sheet steel HS GOST 10994-74 thickness of 0.02 to 0.05 mm cut zastavki plates.

Make the puck rigidity 28 bronze Br.NBT THE 48-21-92-72 with polishing the same plane and made the ring busbar 20 bronze Br.NBT 48-21-92-72 with polishing the same plane.

Assemble washers rigidity 28, blanks strips of steel and billet plates of bronze in an alternating and ring electrical power supply 20 in the conductor. Mark washer hardness 28 and the ring current lead 20 to one line, perform the Central hole and the holes for mounting, cut threads in the holes for the fastener and the washer hardness 28, disassemble the package, labeled plates of bronze, degrease the workpiece strips of steel and plates of bronze to obtain the necessary electrical resistance, are subjected to thermal oxidation of the workpiece strips at a temperature of 600...650With over 10...15 min to obtain the insulating gasket 30 with steady uniform in color oxide film is subjected to thermal oxidation bronze plate 29 at a temperature of 600...650With over 35...40 seconds to obtain a stable homogeneous color of the oxide film. Carry out a preliminary Assembly, which collect the package in accordance with the marking in alternating pooladi 30) and so on, on the polished surface of the ring busbar 20 is placed on top of the washer hardness 28 ground surface inside the package and subjected to compression with a force of 5000 5100...kgf aged 5...6 minutes manipulate the external surface of the package in the specified size, the sheets are cut package on three sectors 25 by the number of petals of a three-gripper 12, the final machining of the surface of the sectors 25 and grinding. Fix sector 25 package (hereinafter mold-refrigerator-current lead 24) in a three-Tsang, carry out the compression with a force of 2500...2600 kgf aged 72...74 hours at a temperature of 20...25With, followed by tightening of the fastening screws 31 which are insulated from the plates 29 and insulating strips 30 insulators 32 and epoxy resin.

The parameters of the production molds-refrigerator-electrical power supply 24 is optimal, and any deviation in more or less side leads to marriage in contact butt welding of the shell 9 of the fuel element with the cap 11, and provides the necessary electrical resistance.

The unit flash butt welding of fuel elements in the automatic line works as follows.

Using reversible motors unit 8 ass is mounted nuclear fuel 26 with a fixed 27 shell 9 is inserted open end of one of the welding chambers 1 and is fixed roller clamp 44 and pneumatic clamp 45.

At the same time when the vibrator 34 of the two vibrates 35 stub 11 through the trays 36 are received in the chute 37, and through the photosensor 38 piece through the cutter 39 plug fits in to the cradle 40, decalcified cylinder 41 and the cylinder 43 and the device 10 is introduced into one of the cameras welding 1, where the pneumatic cylinder 42, the plug 11 is inserted in the Chuck 13 and the cradle 40 is withdrawn from the zone of welding pneumatic cylinder 43.

Using tubular rods 14, are placed in end-to-end channels 4 units and actuator 16, a three-collet 12 fixes the shell 9 of the fuel element in part 3, and with the tubular rod 15, is placed in a through channel 5, with the actuator 17 of the cap 11 is fixed in part 2 in the collet clamp 13. Then part 2 and 3 are closed, forming a weld zone along generatrix 33. The tool 6 is communicated with a vacuum system through pipe 46. After evacuating the cavity of the fuel element is filled with a neutral gas (helium) from the cylinder 7, and the drive of the welding pressure 18, acting on the actuator 17, docks cap 11 with the shell 9 of the fuel element. From source 19 of the welding current through the mold-refrigerator-current lead 24, which combines the mold 21, the current lead 20 and means 22 DL is, when the welding current flows through the outer cylindrical layers of the working part of the stub 11 and all of the cross-section of a welded area of the shell 9, heating the blank only its outer layers, while Shrivenham area of the shell 9 are heated inner layers, resulting in deformation resistance of the outer layers of the stub 11 and the inner layers of the shell 9 is falling and the stub is included in the end of the pipe.

Thanks to press-form-refrigerator-electrical power supply 24, which combines the mold 21 when welding to prevent Razdolnoe the end of the membrane surfaces into it plugs 11, the output of the outer Burr beyond the outer diameter of the shell, it is possible to create conditions volumetric compression of the weld metal during formation of a weld connection.

Thanks to press-form-refrigerator-electrical power supply 24 combining current lead 20 is a supply of welding current to the shell 9.

Thanks to press-form-refrigerator-electrical power supply 24 combining means 22 of the heat, made of alternating plates 29 of oxidized bronze, insulating steel strips 30, the heat from the outer layers of the shell 9 in the welding zone is allocated, preventing them from heating above its recrystallization temperature and obespechenie field in the sheath 9, in which its inner layers are heated to a temperature equal to the temperature of the outer layers of the working area of the stub 11.

After welding, open the clamps 44, 45 of a three-gripper 12, includes reversible motors on the return stroke, and the fuel element is displayed on the roller table 8 of the unit.

Because of the repeated movement of the collet clamps the sleeve 23, which eliminates damage to the body collet clamps for welding cycles, and eliminates the marriage of the fuel element.

Claims

1. Method of making molds-refrigerator-electrical power supply to the unit flash butt welding, including cutting blanks strips of steel sheet with thickness of 0.02 to 0.05 mm, the cutting of workpieces in the form of plates of sheet bronze with a thickness of 0,3...0,5 mm, manufacturer washer hardness of bronze with polishing the same plane, making rings of the electrical power supply of bronze with polishing the same plane, the Assembly washers stiffness, blanks strips of steel, billet plates of bronze in an alternating and ring current supply to the conductor, marking washers stiffness and ring busbar on one line a Central hole and Finance plates of bronze, degreasing, thermal oxidation of the workpieces strips of steel and plates of bronze to form a stable homogeneous color of the oxide film, the implementation of pre-Assembly, in which the ring busbar collect the package in accordance with the marking in alternating sequence in the form of a billet plate of bronze, then billet steel plate, placing on the polished surface of the ring busbar on top of the washer hardness polished surface inside the package and compress with exposure time, the consolidation package screws, fill the gaps between the screws and the package with a mixture of epoxy resin with hardener, installation of insulators and final tie of the bag of screws the shutter speed in the compressed state, the processing of the external surface of the package in the specified size, cutting package on three sectors according to the number of petals of a three collets, the final machining of the surfaces of the sectors and their grinding, fixing sectors of the package in a three-Tsang with the formation of the mold-refrigerator-electrical power supply, compression and tightening the mounting screws until snug.

2. The method according to p. 1, characterized in that the material of the gaskets used steel NS.

3. The method according to p. 1, otlichayuschimisya fact, for washers stiffness and ring busbar use bronze Bmbt.

5. The method according to p. 1, wherein thermal oxidation billet spacers is carried out at a temperature of 600650Swithin 10-15 min with getting the insulating strips.

6. The method according to p. 1, wherein thermal oxidation of plates of bronze is carried out at a temperature of 600650Swithin 3545 C.

7. The method according to p. 1, characterized in that the compression of the package carried out with a force of 50005100 kg and aged for 56 minutes

8. The method according to p. 1, characterized in that the shutter speed in the final screed exercise 7274 h at a temperature of 2021C.

9. The method according to p. 1, characterized in that the compression mold-refrigerator-electrical power supply in the collet carried out with a force of 25002600 kg.

 

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