CN110508909A - Stainless steel tube docks the welding system and method for automatic superimposed pulse single-run welding - Google Patents

Stainless steel tube docks the welding system and method for automatic superimposed pulse single-run welding Download PDF

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Publication number
CN110508909A
CN110508909A CN201910727448.6A CN201910727448A CN110508909A CN 110508909 A CN110508909 A CN 110508909A CN 201910727448 A CN201910727448 A CN 201910727448A CN 110508909 A CN110508909 A CN 110508909A
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China
Prior art keywords
welding
tungsten electrode
connector
casing
melting ring
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CN201910727448.6A
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CN110508909B (en
Inventor
赛鹏
孙国辉
王莉
杨云丽
张海梅
王恩泽
王舒伟
崔建龙
隋旭
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Harbin Electric Group Qinhuangdao Heavy Equipment Co Ltd
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Harbin Electric Group Qinhuangdao Heavy Equipment Co Ltd
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Priority to CN201910727448.6A priority Critical patent/CN110508909B/en
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00Arc welding or cutting
    • B23K9/16Arc welding or cutting making use of shielding gas
    • B23K9/167Arc welding or cutting making use of shielding gas and of a non-consumable electrode
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00Arc welding or cutting
    • B23K9/235Preliminary treatment
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K9/00Arc welding or cutting
    • B23K9/32Accessories
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23KSOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2101/00Articles made by soldering, welding or cutting
    • B23K2101/04Tubular or hollow articles
    • B23K2101/06Tubes

Abstract

The present invention provides welding systems and method that a kind of stainless steel tube docks automatic superimposed pulse single-run welding.The system comprises stainless steel butt tube and tig arc welding machines;When welding, the end of casing and connector, the internal diameter of melting ring are processed and cleaned;Assemble casing, connector and melting ring, and spot welding;After welding equipment installation and debugging, welding parameter is set, implements welding.The welding system and method that the stainless steel tube docks automatic superimposed pulse single-run welding can effectively realize effective welding between electric heater casing and connector in the case where voltage-stablizer electric heater is intensive, distance is small, welding operating space is small between pipe;It also can avoid being in the state of overheat when workpiece and long tungsten electrode, so that welding process is stablized, good appearance of weld and welding quality can be obtained.

Description

Stainless steel tube docks the welding system and method for automatic superimposed pulse single-run welding
Technical field
The present invention relates to welding field more particularly to a kind of welding methods, and in particular, to one kind is used for stainless steel tube pair The superimposed pulse single track automatic welding method for welding connect is particularly related to a kind of electricity that S (sulphur) content for voltage-stablizer is very low and adds The automatic welding method of hot device casing and connector.
Background technique
In nuclear power station, the welding of voltage-stablizer electric heater casing and connector is the peculiar structure of such product.Product is total 108 electric heaters are enclosed in setting four, and spacing is small between pipe, only about 80mm, and welding operating space is narrow, can not use landfilling area, Single face welding and double face shaping can only be realized using melting certainly, and this weld seam needs are welded in horizontal position.
It is required according to regulator design, while needing to detect qualified through PT, RT after this weld seam butt welding, appearance of weld requirement It is more harsh.It should guarantee that weld seam fusion is good in welding process, it is also necessary to control recessed outside weld seam and convex size, welding is difficult Degree is big, and quality requirement is high.But since stainless steel tube S content is very low, conventional pulse single track automatic welding is unable to satisfy through welding and wants It asks.
Based on above-mentioned difficulties, the present inventor studies existing stainless steel tube welding technique, to design one kind Welding efficiency is high, and welding process is stablized, and weld seam fusion is good, and the welding side that weld seam surfaces externally and internally size satisfies the use demand Method.Therefore, the present invention provides welding systems and method that a kind of stainless steel tube docks automatic superimposed pulse single-run welding.
Summary of the invention
To solve the above-mentioned problems, present inventor has performed sharp studies, as a result, it has been found that: by tig arc welding machine using specific Welding parameter austenitic stainless steel butt tube can be welded, can produce after selecting specific tungsten electrode and welding method Compression and the good electric arc of straightness, in overheat when also can avoid workpiece and long tungsten electrode in the case where the fusion penetration of guarantee weld seam Under state, stablizes welding process, obtain good appearance of weld and welding quality, so as to complete the present invention.
The purpose of the present invention is to provide following aspect:
In a first aspect, the present invention provides the welding method that a kind of stainless steel tube docks automatic superimposed pulse single-run welding, it should Welding method the following steps are included:
(1) end of casing and connector, the internal diameter of melting ring are processed and is cleaned;
(2) casing, connector and melting ring, and spot welding are assembled;
(3) after welding equipment is installed and debugged, welding parameter is set, implements welding.
Wherein, in step (2), melting ring clamping is set between casing and connector, spot welding after fixing.
Further, in step (3), the welding equipment is tig arc welding machine, is provided with tungsten electrode;
The tungsten electrode includes tungsten electrode bar, tungsten electrode end circular cone and the tip platform being arranged on the circular cone of tungsten electrode end.
Preferably, in step (3),
The diameter of the tungsten electrode bar is 2~2.8mm, preferably 2.2~2.6mm;
The coning angle of tungsten electrode end circular cone is 25 °~40 °, preferably 28 °~38 °;
The diameter of the tip platform is 0.1~0.5mm, preferably 0.2~0.4mm.
Further, in step (3), the distance of tungsten electrode point to welding region pipe outer wall is 1.0~2.0mm, more preferably For 1.3~1.7mm.
Wherein, in step (3), background current be 40~45A, peak point current be 70~75A, superimposed current be 90~ 110A;
Base value time/time to peak is 250~400ms, preferably 280~350ms;The superposition time is 90~110ms;
Weldingvoltage is 17~20V.
Wherein, in step (3), front protecting gas is helium, and front protecting gas flow is 10~35L/min, excellent It is selected as 12~30L/min;
Backing gas is argon gas, and backing gas flow is 10~45L/min, preferably 15~40L/min.
Second aspect, the present invention also provides a kind of stainless steel tubes to dock automatic superimposed pulse single-run welding system, the system System includes stainless steel butt tube, melting ring and tig arc welding machine;
Wherein, the stainless steel butt tube includes the casing and connector of Butt Assembling, and melting ring is set to casing and company Between fitting;
The inner wall of end of casing and connector is circumferentially recessed, and makes the inner end diameter Φ of casing and connectorIt is interior24~28mm, Preferably ΦIt is interior25~27mm, most preferably 26mm;
The internal diameter of melting ring is ΦIt is interior27.5~28mm;
Melting ring with a thickness of 0.4~0.6mm, preferably 0.5mm.
Further, the tig arc welding machine includes tungsten electrode, and the tungsten electrode includes that tungsten electrode bar, tungsten electrode end circular cone and setting exist Tip platform on the circular cone of tungsten electrode end.
It preferably, further include positioning tool in the system.
The stainless steel tube provided according to the present invention docks the welding system and method for automatic superimposed pulse single-run welding, have with It is lower the utility model has the advantages that
(1) welding system provided by the invention and method realize the very low stainless steel Z2CND18-12NS material of S content Pipe docking, and pipe butt filling material is used as using the melting ring of specific materials and size, had under the welding parameter being applicable in Effect ensure that weldquality and forming;
(2) welding system provided by the invention and method use superimposed pulse automatic TIG welding to connect technique, weld in normal TIG On the basis of superimposed pulse again, generate compression and the good electric arc of straightness, also can avoid in the case where guaranteeing the fusion penetration of weld seam When workpiece and long tungsten electrode in the state of overheat, this method can welding parameters and process be programmed control, welding process Stablize, good appearance of weld and welding quality can be obtained;
(3) intensively, between pipe distance is small, welds behaviour in voltage-stablizer electric heater for welding system provided by the invention and method Make space it is small in the case where, it can be achieved that effective welding between electric heater casing and connector;
(4) welding system provided by the invention and method carry out butt welding to casing and connector, can reach good weldering It is seamed into shape and weld seam fusion, meets the welding quality requirement of regulator products electric heater.
Detailed description of the invention
Fig. 1 shows the structural schematic diagram of a kind of welded workpiece casing of preferred embodiment, melting ring and connector;
Fig. 2 shows a kind of structural schematic diagrams of the tungsten electrode of preferred embodiment;
Fig. 3 shows a kind of structural schematic diagram of the positioning tool of preferred embodiment;
Fig. 4 shows the structural schematic diagram of pedestal in a kind of positioning tool of preferred embodiment.
Drawing reference numeral explanation:
1- casing
2- melting ring
3- connector
4- tungsten electrode bar
5- tungsten electrode end circular cone
The tip 6- platform
11- lock-screw
12- pressing plate
13- bracket
14- pedestal
15- hook
16- welds window
Specific embodiment
Present invention will now be described in detail, the features and advantages of the invention will with these exemplary illustrations and It becomes more apparent from, is clear.
Dedicated word " exemplary " means " being used as example, embodiment or illustrative " herein.Here as " exemplary " Illustrated any embodiment should not necessarily be construed as preferred or advantageous over other embodiments.Although each of embodiment is shown in the attached drawings In terms of kind, but unless otherwise indicated, it is not necessary to attached drawing drawn to scale.
The present invention described below.
In nuclear power station, voltage-stablizer electric heater casing and the butt-welded requirement of connector are very high, this weld seam is through PT While (liquid penetration examination), RT detect (ray detection) qualification, weld seam outer wall depression depth is no more than 0.5mm, and inner wall is convex It plays height and is no more than 1.5mm.
Described sleeve pipe 1 and connector 3 in a tubular form, are made of austenitic stainless steel, preferably control nitrogen stainless steel, more preferably Control nitrogen stainless steel Z2CND18-12NS.
Other workpiece are also accommodated in the tubular space of casing 1 and connector 3, also, internal workpiece is very close The inner wall of casing 1 and connector 3.When installation, need just to can be carried out casing 1 and connector 3 after internal workpiece is installed It is welded and fixed.Due to the hypotelorism of internal workpiece and 3 tube wall of casing 1 and connector, the thermal stress in welding process is easy to Thermal damage is generated to internal workpiece.
For the ease of the installation of other workpiece, and, to the heat waste of internal workpiece when reduction casing 1 and connector 3 weld Circumferentially recess reduces pipe thickness to the inner wall of end of wound, casing 1 and connector 3, to expand the inside of casing 1 and connector 3 Space, to accommodate and other workpiece in guard space.
Preferably, the circumferentially round and smooth recess of the inner wall of end of casing 1 and connector 3, makes the end pipe of casing 1 and connector 3 Wall thickness is gradually reduced to endface.
Using casing 1 and 3 junction of connector as benchmark line, respectively it is no more than at 100mm, no less than 30mm along reference line two sides Form the welding region of casing 1 and connector 3;Preferred weld region is no more than each 80mm in reference line two sides and is no less than 20mm。
In welding region, the outer diameter of casing 1 and connector 3 is ΦOutside32.5mm;Internal diameter is ΦIt is interior24~28mm, preferably ΦIt is interior25~27mm.The use demand that the internal diameter can satisfy receiving and protect internal workpiece, ensure tube wall stress after welding.
In a preferred embodiment, the welding region pipe outside diameter of casing 1 and connector 3 is ΦOutside32.5mm, in pipe Diameter is ΦIt is interior26mm, wall thickness 3.25mm.
Since electric heater is numerous in voltage-stablizer, the welding narrow space of casing 1 and connector 3, and control nitrogen stainless steel S (sulphur) content is extremely low in Z2CND18-12NS, and conventional pulse single track automatic welding can not penetrate the stainless steel tube, also can not butt welding The recess and protrusion of seam carry out good control.
Based on this, the present invention provides a kind of welding methods, dock automatic superimposed pulse single-run welding for stainless steel tube Welding;Preferably, for the welding between the stainless steel tube with melting ring;In particular for the electric heater casing of voltage-stablizer Welding between 1 and connector 3.
The welding method the following steps are included:
(1) end of casing 1 and connector 3, the internal diameter of melting ring 2 are processed and is cleaned;
(2) casing 1, connector 3 and melting ring 2, and spot welding are assembled;
(3) after welding equipment is installed and debugged, welding condition is set, implements welding.
It in welding method provided by the invention, casing 1 and 3 Butt Assembling of connector and is welded and fixed, melting ring 2 is arranged Between casing 1 and connector 3, as the packing material that casing 1 and connector 3 weld, by 3 docking point of casing 1 and connector Solid welding is fixed, as shown in Figure 1.
In step (1),
According to the material property of casing 1 and connector 3, in order to keep melting ring 2 and casing 1 and connector in welding process 3 good fusion, the preferably described melting ring 2 is prepared by ferritic stainless steel, more preferably by the ferrite stainless of Z01CD26-01 Steel is made, such as the cyclic annular packing material being process by the bar of the material.The melting ring 2 of the material preparation can improve Seam organization and the corrosion resistance for improving weld seam.
In addition, after welding, on the inside of weld seam it is general all can outwardly convex, casing 1 and connection can be damaged when height of projection is higher Workpiece in part 3;And the intensity of tube wall can be reduced when cup depth is larger since gravity is recessed inwardly on the outside of weld seam.
In order to guarantee that casing 1 and connector 3 fuse well, while the height of weld flush and the depth of recess are controlled, one Aspect can be controlled by the internal diameter of setting casing 1 and connector 3 with wall thickness, and weld seam is made to meet requirement;Another party Face, it is also necessary to which the internal diameter, wall thickness and thickness of melting ring 2 are processed and controlled.
Further, the outer diameter of the melting ring 2 is identical as 1/ connector 3 of casing, but internal diameter is larger, to reduce melting ring Accounting of 2 metals formed in entire molten bath, guarantees the penetration effect of weld seam.
Preferably, the internal diameter of the melting ring 2 is ΦIt is interior27.5~28mm.
If using melting ring 2 along axial height as the thickness of melting ring 2, the melting ring 2 with a thickness of 0.4~ 0.6mm, preferably 0.5mm.
The end face vehicle of casing 1 and connector 3 is flat, does not need finished edge.
When welding, melting ring 2 is located between 3 welding region of casing 1 and connector, keeps weld seam fusion good same When also improve seam organization.By the cooperation of melting ring 2 and casing 1 and connector 3, the behaviour that welding wire is conveyed when welding is eliminated Make, reduces the influence of manual operation, and welding operation difficulty, be conducive to the control of welding quality.
Before by the assembly of casing 1, connector 3 and melting ring 2, welding region preferably to casing 1 and connector 3 and The all surfaces of melting ring 2 are cleaned, and impurity in welding process is avoided to mix into weld seam, cause stomata, slag inclusion or unmelted The weld defects such as conjunction.
Stringent clean to non-woven fabrics dip in acetone wiping and it is non-discolouring, it is ensured that cleaning quality.
Preferably, when cleaning, if the defect of the jagged equal influences welding of the welding region surface of casing 1 and connector 3, makes The defect is removed with file, then dips acetone or alcohol to pipe the inside and outside wall at least range of 20mm and melting ring 2 with non-woven fabrics All surfaces carry out wiping until non-woven fabrics it is non-discolouring, think that welding region is clean at this time.
In step (2),
When assembling casing 1, connector 3 and melting ring 2, the clamping of melting ring 2 is set between casing 1 and connector 3.
It is preferred that retaining sleeve 1, connector 3 and 2 axis vertical of melting ring are fixed, to guarantee that three is coaxial, no in assembly Misalignment, gapless, to guarantee welding quality.
In the present invention, assembly positioning can be carried out to casing 1, connector 3 and melting ring 2 using tooling.The tooling As long as can be used for the axial alignment of minor diameter pipe butt welding and fix, minor diameter commonly used in the prior art can be used Pipe centralising device.
The tooling includes pedestal for clamping minor diameter pipe to be welded and pressing plate and other associated components.Pass through Holding screw is fixed, and tooling is removed after tack-weld.
In a preferred embodiment, the tooling is positioning tool, as shown in figure 3, including lock-screw 11, pressure Plate 12, bracket 13, pedestal 14 and hook 15.
Wherein, pedestal 14 is in flanged pin U-shaped structure.Pipe is located at U-shaped opening, on pedestal 14 with workpiece contact position It is rounded structure, prevents plowing from pipe.
U-shaped bottom is not contacted with pipe on pedestal 14, is provided with welding window 16, and welding gun can pass through the welding window 16 protrude into inside tooling and fix electrical heating elements connector 3, melting ring 2,1 spot welding of casing.
Preferably, the pedestal 14, as shown in figure 4, welding window 16 is set to the middle part of pedestal 14, leads to substantially at I-shaped The Aligning degree for observing welded workpiece that the recess portion of 14 two sides of pedestal can be convenient is crossed, it is easy to adjustment in time;And form spot welding Space carries out spot welding processing.
Preferably, it on a flange of pedestal 14, does not contact with 3/ casing 1 of connector and close to the one of U-shaped bottom Inclined-plane is formed slopely towards welded workpiece.15 cooperation of the inclined-plane and hook, makes hook 15 be not easy to slide from pedestal 14.
It is equipped with supporting leg at two on notching construction, with bracket 13 on another side flange of pedestal 14 and forms hinge-connection.
Bracket 13 is the two sides body frame structure with dog-ear, and on one side in the flat-tope structure of both ends indent, another side is The two supporting legs connect with 14 flange hinge of pedestal.
It is preferred that the flat-tope structure with pedestal 14 of both ends indent is corresponding in bracket 13, the more preferable face is also in I-shaped substantially Shape, in the Aligning degree for the observation welded workpiece that inner fovea part can be convenient;And spot welding space is formed, carry out spot welding processing.
Link up with 15 L-shaped, one end far from hook connects with flat-top end hinge I-shaped in bracket 3, hook and bottom 14 upper flange contact of incline plane of seat, it is tight or loose when being acted together with lock-screw 11, play the role of positioning or disassembling fixture.
Preferably, lock-screw 11, preferably flush end housing screw are set in the middle part of the I-shaped flat-top of bracket 3.
The pressing plate 12 for the slot that is in U-shape is provided with close to one end of pipe in lock-screw 11, U-lag is open towards to be welded Workpiece.The width of the pressing plate 12 is much smaller than the width of pedestal 14, as shown in figure 3, connecing thereon with workpiece (1/ connector 3 of casing) Synapsis is rounded structure, can prevent plowing from pipe.The screw thread connecting with lock-screw 11 is provided in U-lag middle Hole contacts 11 end of lock-screw with workpiece.
Lock-screw 11 links together bracket 13, pressing plate 12, and when tightening lock-screw 11, clamping platen 12 makes It is contacted with workpiece, and then fixed workpiece.
When using the positioning tool, lock-screw 11 is unclamped, hook 15 is opened, covers and assembling from the side of workpiece Welding position at, close hook 15, lock-screw 11 fastened, until connector 3, melting ring 2, casing 1 do not occur in axis It is mobile, spot welding is carried out at this time to be fixed.
The positioning tool forms approximate three-point fix by the positioning surface on the positioning surface and pressing plate 12 on pedestal 14, will 1 three connector 3, melting ring 2, casing axis are locked on the same center line, realize the positioning of three.
In addition, the recess portion by the way that pedestal 14 is arranged in, on bracket 13 is that spot welding forms spot welding space, in addition on pedestal 14 Welding window 16, form biggish spot welding space at three in approximate 120 ° of distributing positions in total, meet spot welding requirement.
The operation such as welding gun trial assembly can be carried out in the spot welding space of the positioning tool, to determine that welding gun is loaded orientation, In In the case where guaranteeing that spot welding position and starting the arc position can satisfy welding demand, then positioning tool fastened, makes the docking of pipe Gapless, staggered edge free are held, is welded after tooling disassembly, tig arc welding machine is especially able to use and completes Full-automatic welding.
The positioning tool overall structure is small and exquisite, is not limited by the space of 3/ casing 1 of electric heating casing and connector.
Method using tooling assembly casing 1, melting ring 2 and connector 3 is as follows: any pipe being put into tooling bottom first On seat, adjustment pipe end position to be welded to setting position, then melting ring 2 and another pipe are put into, pass through tightly after adjusting good position Determine screw adjustment pressing plate fastening, keeps 1/ connector 3 of casing and melting ring 2 coaxial, then spot welding is fixed, structure such as Fig. 1 after assembly It is shown.
The centre of gyration of preferred weld head drives tungsten electrode to carry out automatic welding or spot welding around the rotation of melting ring 2.
After the completion of spot welding, positioning tool is removed, then carry out the installation and debugging of welding equipment.
In step (3),
The welding equipment is automatic TIG welding machine, and TIG automatic welder welding parameters can be programmed and store in advance, Relevant parameter is realized in the welding process and is finely controlled, effectively control thermal weld stress, pool size and shape, reduces welding Influence of the human factor to weldquality in the process, is particularly suitable for one side welding with back formation, can better ensure that weld seam at Shape and welding quality.
It, can be by the welding head clamping of welding equipment in pipe since casing 1 and the docking of connector 3 need to carry out annular welds On, the centre of gyration of welding head is welded around the rotation of melting ring 2.
As shown in Figure 1, after the casing 1 assembled, connector 3 and 2 axis of melting ring are vertically fixed, tungsten electrode and pipe axis Vertically, the centre of gyration of welding head drives tungsten electrode to be rotated in horizontal position welding position and carries out pipe automatic welding.
When horizontal position is welded, liquid metal inevitably has inclining for flowing under gravity and surface tension effects To, the phenomenon that face of weld recess can inevitably occur, so need in the welding process guarantee weld seam complete penetraction and fusion in welding While control appearance of weld again.
It is preferred that the equipment positioning device by welding head guarantees the welding gun centre of gyration and stainless steel tube to be welded (i.e. casing 1 With connector 3) center is consistent.When welding, pipe axis is perpendicular to horizontal plane, by the welding position of automatic TIG welding machine It is loaded on pipe, the centre of gyration on welding head is rotated around melting ring 2 completes welding.
For the butt welding of casing 1 and connector 3, since diameter is small and wall thickness is big, S content is extremely low in material, makes Both welding difficulty is big, welding parameters are sensitive.
Repeatedly the study found that in welding process preferably by the way of impulse welding, to guarantee to melt casing 1 and connector 3 Thoroughly, increase superimposed pulse on the basis of thermal pulse, generate compression and the good electric arc of straightness, guaranteeing that weld penetration meets need Asking down also can avoid is in the state of overheat when workpiece and long tungsten electrode, keeps appearance of weld uniform, welding process is stablized.
When welding, the type of tungsten electrode will have a direct impact on the effect of welding.In the present invention, the tungsten electrode can select lanthanum tungsten Pole or thoriated tungsten electrode are, it is preferable to use lanthanum tungsten electrode.
The electric conductivity of lanthanum tungsten electrode and 2% thoriated tungsten electrode are close, and durable electric current is high and burn out rate is minimum.The service life ratio of lanthanum tungsten electrode Thoriated tungsten electrode is longer, and lanthanum tungsten electrode is "dead" compared to thoriated tungsten electrode, and in welding, the starting the arc is easier, and striking and stabilising arc performance are excellent It is good.
Tungsten electrode end shape directly affects the emissivities of tungsten electrode electronics to influence joint penetration effect.Tungsten electrode end circle The coning angle of cone increases, and arc column diffusion causes fusion penetration to reduce, and molten wide increases;As coning angle is reduced, arc column diffusion tendency subtracts Few, fusion penetration increases, and molten wide reduces.Tungsten electrode tip platform size increases, and arc column diffusion causes fusion penetration to reduce;Tungsten electrode tip platform Undersized, tungsten electrode scaling loss is serious.
By repeatedly studying, in the present invention, according to casing 1, the material of connector 3 and melting ring 2, specification and nuclear power It stands firm the welding requirements of depressor middle sleeve 1 and connector 3, has investigated the tungsten electrode of specific model.
Wherein, as shown in Fig. 2, the tungsten electrode includes tungsten electrode bar 4, tungsten electrode end circular cone 5 and is arranged in tungsten electrode end circular cone 5 On tip platform 6.
Preferably, the diameter of the tungsten electrode bar 4 be 2~2.8mm, preferably 2.2~2.6mm, more preferably 2.3~ 2.5mm, most preferably 2.4mm.
Preferably, the coning angle of tungsten electrode end circular cone 5 is 25 °~40 °, preferably 28 °~38 °, more preferably 30 ° ~35 °.
Further, the diameter of the tip platform 6 is 0.1~0.5mm, preferably 0.2~0.4mm, more preferably 0.2 ~0.3mm.
The tungsten electrode can guarantee appearance of weld and the fusion of casing 1 and connector 3, and tungsten electrode loss is small.
The study found that tungsten electrode will have a direct impact on the welding of weld seam at a distance from melting ring 2 in head after welding head installation The form of quality and surfaces externally and internally.When tungsten electrode and melting ring 2 apart from it is too small when easily cause shaped depression on the outside of weld seam, and be easy Scaling loss tungsten electrode causes weld seam tungsten inclusion;When tungsten electrode and melting ring 2 apart from it is excessive when cannot be guaranteed welding arc stablility, influence to weld matter Amount.
Preferably, control tungsten electrode point to welding region pipe outer wall distance be 1.0~2.0mm, more preferably 1.3~ 1.7mm, tungsten electrode point is directed toward the lower edge of melting ring 2 on the axis direction of welding region pipe.
The distance can guarantee that casing 1 and connector 3 penetrate, and reduce the convex height and outer recessed depth of weld seam.
In the present invention, in welding, welding current is the main parameter for determining weld penetration, and welding current is big, fusion penetration Increase;Exoncoma easy to form and the defects of burn when welding current is excessive also results in undercut, recessed outside weld seam oversized etc. lacks It falls into;And electric current is small, incomplete fusion easy to form and it is lack of penetration the defects of.
Due to the pipe diameter very little of welding region, only it is suitable for single welding, to guarantee single face welding and double face shaping, for S content The material of very low infusibility is superimposed peak point current in short-term in the welding process, when guaranteeing weld seam energy penetration, but being unlikely to long It overheats and makes tungsten electrode scaling loss, type is recessed into outside weld seam and is difficult to control.
Preferably, in the present invention, background current be 40~45A, peak point current be 70~75A, superimposed current be 90~ 110A, to reach good appearance of weld and weld seam fusion.
Further, base value time/time to peak is 250~400ms, preferably 280~350ms, more preferably 300ms;The superposition time is 90~110ms.
Preferably, weldingvoltage is 17~20V,
Speed of welding welding quality is equally important, and too fast speed of welding can make the atmosphere of front protecting gas broken Bad, weld seam is easy to produce lack of penetration and stomata;When speed of welding is too slow, weld seam is easy burn-through and undercut.The selected welding of the present invention 55~60mm/min of speed, to meet welding requirements.
Particularly, the present invention selects two groups of protection gas, carries out welding guarantor respectively outside welding region pipe and inside pipe Shield.
Preferably, front protecting gas is helium, the more preferably helium of purity >=99.999%.The ionization energy of helium compared with Height, thermal conductivity is big, and under same weld electric current and arc length, the arc voltage of heliarc welding is high, and arc energy density is high, arc column Carefully to concentrate, heliarc has bigger penetration, therefore using helium as front protecting gas in the present invention.
Further, backing gas is argon gas, preferably the argon gas of purity >=99.999%.Argon gas density is big, makes Used time is not easy floating and scatters and disappears, and after argon gas outflow, can form stable airflow layer, while its thermal capacity and thermal conductivity very little, In It can avoid the loss of welding heat when protecting welding position, therefore select argon gas as the backing gas inside access tube.
The study found that shield gas flow rate is too small, air-flow stiffness is poor, and the ability for excluding surrounding air is weak, and slight is lateral Wind can also cause a deviation from it is at random, protecting effect is bad.Flow is excessive, and the air-flow laminar flow of ejection is very thin, or even forms turbulent flow, protects It is also bad to protect effect.
Preferably, front protecting gas flow is 10~35L/min, more preferably 12~30L/min.
Further, backing gas flow is 10~45L/min, preferably 15~40L/min.
By the stringent setting of welding parameters, the control action to molten bath or liquid metal can be played, so that liquid Influence of the metal flow to weld size is controllable, it is ensured that molten bath and pipe fusion are good.Pass through arc force, molten bath self gravity, table Face tension reaches balance, so that welding process is steady, welding quality is high, avoids the defect being likely to occur in welding process.And Electric arc with above-mentioned parameter just can effectively control the form in molten bath and the fusion effect with pipe, so that casing 1 and connection The sidewall fusion of part 3 is good, can obtain good appearance of weld and welding quality, makes stainless steel tube casing 1 and connector 3 Docking has reached good welding effect.
It before implementing pipe butt welding, preferably installs, debug welding equipment, welding equipment is checked, guarantee that each route connects It is normal to connect correct, each function, the meet demands such as welding gas.
Butt welding of the welding method provided by the invention for stainless steel tube casing 1 and connector 3, can reach good Appearance of weld and weld seam fusion, meet the following quality requirement of regulator products electric heater welding.
Testing result is as follows after the stainless steel tube welding:
Visual detection: postwelding even weld is visible by naked eyes defect.
Liquid Penetrant: surface is without any display.
Ray detection: flawless, undercut, incomplete fusion, lack of penetration;No full-size is greater than any single gas of 0.75mm Hole;No any accumulative size is greater than the threadiness or porosity of 1.6mm.No full-size greater than 1mm any isolated slag inclusion or Slag inclusion group;It is discontinuous that weld metal zone does not occur geometry.
Room temperature tensile: tensile strength >=520MPa.
Face is curved, root bend test: 180 ° of bending angle, any direction is greater than the crackle of 3mm without single length on Extrude Face Or defect.
Metallographic test: the defects of butt weld and heat affected area are without any crackle, lack of penetration, incomplete fusion, stomata, outer wall is recessed It falls into and is no more than 0.5mm, inner wall protrusion is no more than 1.5mm.
Intercrystalline corrosion: welding point is inclined to without intercrystalline corrosion under as-welded and sensitization.
Welding method provided by the invention can weld the butt weld of the stainless steel tube of square groove, and welding process is steady Fixed, appearance of weld is beautiful, can obtain the welding quality for meeting nuclear power station product requirement.Also achieve very low stainless of S content The automatic TIG welding of tube material connects, and welding process is stablized, and can be effectively controlled weldquality and appearance of weld.
The present invention also provides a kind of stainless steel tubes to dock automatic superimposed pulse single-run welding system, and the system comprises stainless Steel butt tube, melting ring 2 and tig arc welding machine.
Wherein, the stainless steel butt tube includes the casing 1 and connector 3 of Butt Assembling and welding, and melting ring 2 is located in Between casing 1 and connector 3.
Preferably, the inner wall of end of casing 1 and connector 3 is circumferentially recessed, and preferably round and smooth recess is to improve internal diameter, so that set The inner end diameter of pipe 1 and connector 3 is ΦIt is interior24~28mm, preferably ΦIt is interior25~27mm, most preferably 26mm.
Wherein, the outer diameter of the melting ring 2 is identical as the outer diameter of casing 1 and connector 3, and the internal diameter of melting ring 2 is greater than set The internal diameter of pipe 1 and connector 3.Preferably, the internal diameter of the melting ring 2 is ΦIt is interior27.5~28mm;More preferable outer diameter is ΦOutside 32.5mm。
In order to guarantee the penetration effect of weld seam, the melting ring 2 with a thickness of 0.4~0.6mm, preferably 0.5mm.
In welding system provided by the invention, by using the melting ring of specific dimensions as pipe butt filling material, make S The very low casing 1 of content and connector 3 ensure that appearance of weld and good welding quality under applicable welding condition.
The tig arc welding machine includes tungsten electrode, and the tungsten electrode includes tungsten electrode bar 4, tungsten electrode end circular cone 5 and is arranged in tungsten electrode end Tip platform 6 on circular cone 5.
Wherein, the diameter of the tungsten electrode bar 4 be 2~2.8mm, preferably 2.2~2.6mm, more preferably 2.3~2.5mm, Most preferably 2.4mm;
Preferably, the coning angle of tungsten electrode end circular cone 5 is 25 °~40 °, preferably 28 °~38 °, more preferably 30 ° ~35 °;
The diameter of the tip platform 6 is 0.1~0.5mm, preferably 0.2~0.4mm, more preferably 0.2~0.3mm.
The tungsten electrode can guarantee appearance of weld and the fusion of casing 1 and connector 3, and tungsten electrode loss is small.Using superposition Pulse automatic TIG welding connects technique, and superimposed pulse, generation are compressed and the good electric arc of straightness, In again on the basis of normal TIG weldering Guarantee also to can avoid being in the state of overheat when workpiece and long tungsten electrode in the case where the fusion penetration of weld seam, welding process is stablized, can To obtain good appearance of weld and welding quality.
Further, it further includes positioning tool that the stainless steel tube, which docks in automatic superimposed pulse single-run welding system,.
Welding system provided by the invention and method carry out butt welding to casing and connector, can reach good weld seam at Shape and weld seam fusion meet the welding quality requirement of regulator products electric heater.
Embodiment
Embodiment 1
The internal diameter of casing made of Z2CND18-12NS steel and connector is 26mm, and internal diameter made of Z01CD26-01 steel is 28mm, the melting ring with a thickness of 0.5mm after docking, are fixed, spot welding using positioning tool shown in Fig. 3 and Fig. 4.
Positioning tool includes the pedestal 14 of flanged pin U-shaped structure, the two supporting legs hinge-connection of a side flange and bracket 13;Branch Frame 13 is two sides shape frame, and in the other end and 15 hinge-connections of L-shaped hook, hook 15 is hooked with another side flange of pedestal 14 to be connected It connects.It is connect by lock-screw 11 with the pressing plate 12 for the slot that is in U-shape in bracket 13 with 14 opposite side of pedestal, to casing, connector It is fixed with melting ring.
Point postwelding, removes positioning tool, and tig arc welding machine carries out automatic welding.Wherein, the diameter of tungsten electrode bar 4 is 2.4mm;Tungsten electrode The coning angle of end circular cone 5 is 33 °;The diameter of tip platform 6 is 0.3mm.
Welding parameter is as follows:
The distance of tungsten electrode point to welding region pipe outer wall is 1.5mm;
Background current is 40~45A, and peak point current is 70~75A, and superimposed current is 90~110A;The base value time/peak value Time is 300ms;The superposition time is 90~110ms;Weldingvoltage is 17~20V.
Front protecting gas is helium, and flow is 12~30L/min;Backing gas is argon gas, flow is 15~ 40L/min。
It is as follows to the testing result of weld seam after welding:
Visual detection: postwelding even weld is visible by naked eyes defect;
Liquid Penetrant: surface is without any display;
Ray detection: flawless, undercut, incomplete fusion, lack of penetration;No full-size is greater than any single gas of 0.75mm Hole;No any accumulative size is greater than the threadiness or porosity of 1.6mm.No full-size greater than 1mm any isolated slag inclusion or Slag inclusion group;It is discontinuous that weld metal zone does not occur geometry.
Room temperature tensile: tensile strength 633MPa;
360 DEG C of high temperature stretchings: tensile strength 446MPa;
Face is curved, root bend test: 180 ° of bending angle, any direction zero defect on Extrude Face;
Metallographic test: the defects of butt weld and heat affected area do not find crackle, lack of penetration, incomplete fusion, stomata, outer wall is recessed Fall into 0.40mm, inner wall protrusion 0.52mm.
Intercrystalline corrosion: welding point is inclined to without intercrystalline corrosion under as-welded and sensitization.
It is described the invention in detail above in conjunction with detailed description and exemplary example, but these explanations are simultaneously It is not considered as limiting the invention.It will be appreciated by those skilled in the art that without departing from the spirit and scope of the invention, Can be with various equivalent substitutions, modifications or improvements are made to the technical scheme of the invention and its embodiments, these each fall within the present invention In the range of.Scope of protection of the present invention is subject to the appended claims.

Claims (10)

1. the welding method that a kind of stainless steel tube docks automatic superimposed pulse single-run welding, which is characterized in that the welding method includes Following steps:
(1) end of casing (1) and connector (3), the internal diameter of melting ring (2) are processed and is cleaned;
(2) casing (1), connector (3) and melting ring (2), spot welding are assembled;
(3) after welding equipment is installed and debugged, welding parameter is set, implements welding.
2. the method according to claim 1, wherein melting ring (2) clamping is set to casing in step (2) (1) between connector (3), spot welding after fixing.
3. the welding equipment is tig arc welding machine the method according to claim 1, wherein in step (3), In be provided with tungsten electrode;The tungsten electrode includes tungsten electrode bar (4), tungsten electrode end circular cone (5) and is arranged on tungsten electrode end circular cone (5) Tip platform (6).
4. according to the method described in claim 3, it is characterized in that, in step (3),
The diameter of the tungsten electrode bar (4) is 2~2.8mm, preferably 2.2~2.6mm;
The coning angle of tungsten electrode end circular cone (5) is 25 °~40 °, preferably 28 °~38 °;
The diameter of the tip platform (6) is 0.1~0.5mm, preferably 0.2~0.4mm.
5. the method according to claim 1, wherein in step (3), tungsten electrode point to welding region pipe outer wall Distance is 1.0~2.0mm, more preferably 1.3~1.7mm.
6. the method according to claim 1, wherein background current is 40~45A, peak value electricity in step (3) Stream is 70~75A, and superimposed current is 90~110A;
Base value time/time to peak is 250~400ms, preferably 280~350ms;The superposition time is 90~110ms;
Weldingvoltage is 17~20V.
7. the method according to claim 1, wherein front protecting gas is helium, front in step (3) Shield gas flow rate is 10~35L/min, preferably 12~30L/min;
Backing gas is argon gas, and backing gas flow is 10~45L/min, preferably 15~40L/min.
8. a kind of stainless steel tube docks automatic superimposed pulse single-run welding system, which is characterized in that the system comprises stainless steels pair Adapter tube, melting ring (2) and tig arc welding machine;
The stainless steel butt tube includes the casing (1) and connector (3) of Butt Assembling, melting ring (2) be set to casing (1) and Between connector (3);
The inner wall of end of casing (1) and connector (3) is circumferentially recessed, and makes the inner end diameter Φ of casing (1) and connector (3)It is interior 24~28mm, preferably ΦIt is interior25~27mm, most preferably 26mm;
The internal diameter of melting ring (2) is ΦIt is interior27.5~28mm;
Melting ring (2) with a thickness of 0.4~0.6mm, preferably 0.5mm.
9. system according to claim 8, which is characterized in that the tig arc welding machine includes tungsten electrode, and the tungsten electrode includes tungsten electrode Bar (4), tungsten electrode end circular cone (5) and the tip platform (6) being arranged on tungsten electrode end circular cone (5);Wherein,
The diameter of the tungsten electrode bar (4) is 2~2.8mm;
The coning angle of tungsten electrode end circular cone (5) is 25 °~40 °;
The diameter of the tip platform (6) is 0.1~0.5mm.
10. system according to claim 8, which is characterized in that further include positioning tool in the system.
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