CN106041411A - Method for repairing high-temperature superheater access header - Google Patents

Abstract

A method for repairing a high-temperature superheater access header belongs to the field of thermal power generation and includes the following steps: 1, cutting away the part of a fourth support tube from the bottom of the header to a support tube linear part; 2, making a welding socket hole in the header; 3, changing a connecting tube; 4, welding the connecting tube between the header and the support tube remaining part; 5, thermally treating the welded part online; the welding socket hole is arranged at the original fourth support tube and header welded position on the header and is a stepped hole, including a through hole, a terrace and an expanded hole; the through hole is communicated with the header; the terrace is perpendicular to the through hole, is in a circular shape and is concentric with the through hole; the expanded hole is arranged in the terrace and concentric with the through hole, the defect that the fourth support tube for the high-temperature superheater access container easily experiences weld cracking due to stress produced by insufficient curvature can be overcome, and normal operation of the header can be guaranteed.

Description

A kind of high temperature superheater imports and exports header restorative procedure

Technical field

The invention belongs to steam power plant field, enter particularly to a kind of thermal power plant steam boiler high temperature superheater Outlet header restorative procedure.

Background technology

In thermal power generation corporations, it is dependent on steam boiler combust fuel, water heating is become the steam of High Temperature High Pressure, pushes away Dynamic steam turbine rotates, and drives electromotor to carry out generating electricity；In the application of steam, in order to ensure that steam is unlikely to produce when application Raw too much moisture, often keeps the condition of high temperature of steam, enters into header, be redistributed in each lateral, be beneficial to The reasonable application of steam；In existing high temperature superheater imports and exports header, major part is to use header many distributed about little Pipe, superheater steam pressure 13.7MPa, 540 ° of C of temperature, wherein the material of high temperature superheater header is 12Cr1MoV, conventional rule Lattice are diameter 325 millimeters, wall thickness 50 millimeters, and the material of branched pipe is 12Cr1MoV, and specification is diameter 42 millimeters, wall thickness 5.5 Millimeter, proves through working practice, finds often occur from single 4th base inwards of high temperature superheater outlet header base There is crackle in root, and through repeatedly repairing, this root arm becomes high temperature superheater outlet header and is easily damaged centrostigma.

Summary of the invention

For in the 4th phenomenon that pipe is easily damaged of thermal power plant high temperature superheater outlet header, the present inventor is carried out Conscientiously studying, finding out its reason is that the 4th arm occurs that due to position limitation curvature is inadequate, causes when expanding with heat and contract with cold the At four arms and header welding, stress is excessive, cracks, and the method used when repairing is incorrect, and therefore, the present invention carries Go out a kind of high temperature superheater import and export header restorative procedure, it is characterised in that: comprise the following steps: 1, by the 4th arm from Header root excises to arm straight line portion；2, in header, welding bore is made；3, connecting tube is changed；4, connecting tube is welded To between header and arm remainder；5, the part that butt welding is taken over carries out burning optimization on line；Described step 1 is employing instrument Seam is had the arm of crackle, cuts off at header, then the other end of arm is cut from the line part of the 4th arm Disconnected, and take off；Described step 2 is at original header the 4th tube socket, re-works the butt hole of branched pipe；Institute The step 3 stated is by the part of the 4th arm removed, and uses the connecting tube of new construction to be replaced；Described step 4 is Between branch holder and the 4th arm of residue that the connecting tube of new construction is welded in header；Described step 5 is to connect Pipe carries out heat treatment, to eliminate stress with header and original 4th arm straight line portion weld and near zone.

Described welding bore is arranged at original 4th arm of header and header welding, for stepped ramp type hole, including Through hole, platform, reaming；Described through hole and header internal run-through；Described platform is vertical with through hole, for circular and same with through hole The heart；Described reaming is arranged on platform, concentric with through hole；Wherein a diameter of 65mm of reaming, hole depth is 4-5mm.

Described connecting tube, including body, the first bending, the second bending, the 3rd bending, step；Described body material Identical with original 4th arm with diameter and wall thickness；The first described sweep is arranged on body top, curved to second The lateral separation of bent portions is not less than 50 millimeters；The second described bending is arranged on the middle part of body, the second described bending section The length divided is not less than 300 millimeters, and transverse curvature is not less than 50 millimeters；The 3rd described bending is arranged on the bottom of body；Institute The step stated is arranged on body two ends, and the outer dia of step part is more than body outer dia 1-2 millimeter.

Burning optimization on line in described step 5 be use electrical heating elements, by the header near weld seam and weld seam and Pipe wraps up, and uses temperature controller that its heating-up temperature is carried out temperature and time control；Electrical heating elements therein is heating Rope；Described heating rope includes heating wire, asbestos cord；Described heating wire is wrapped in the middle of asbestos cord, and two ends are with power supply even Logical；Described asbestos cord swathes the outside at heating wire, it is ensured that heating wire is wrapped without exposed completely, forms flexible heater rope.

Described welding parameter is: butt weld uses complete manual argon welding weldering welding；Welding current 110-120A；Arm pipe Row imports and exports header welding with high temperature superheater, uses plug-in type, angle welding ground floor bottom argon arc welding welding method, one side Weldering double-faced forming, welding current 110-125A, second and third layer R317 welding rod, Ф 3.2mm；Second layer electric current 105-110A, the Three layers of electric current 108-1103A；Use welding machine is ZX7-400S, and striking mode is high-frequency arc strike, and argon arc welding is 160 types model, Torch neck a diameter of Ф 10mm, argon flow amount is 8-10ml, and argon arc welding electrode uses cerium crow extremely rod to be Ф 2.5mm, welding wire type Number being R31, gage of wire is 2.5mm.

Described heat treatment parameter is: heat treatment uses high tempering；Temperature 730 ± 10 DEG C. warming and cooling rate: 125℃/h；Constant temperature time: 210 minutes;In temperature-fall period, temperature can not control below 300 DEG C；Overall process automatically dotting is remembered Record.

Beneficial effect

The beneficial effects of the present invention is, it is possible to overcome owing to high temperature superheater imports and exports the 4th arm of header due to curvature not Enough produce stress and easily cause the defect of bead crack, it is ensured that header normally works.

Accompanying drawing explanation

Fig. 1 is the arm connection diagram that existing high temperature superheater imports and exports header

1. header, 2. the first arm, 3. the second arm, 4. the 3rd arm, 6. the 4th arm.

Fig. 2 is the arm connection diagram that the high temperature superheater after repairing imports and exports header

1. header, 2. the first arm, 3. the second arm, 4. the 3rd arm, 5. connecting tube, 6. the 4th arm.

Fig. 3 is the structural representation of connecting tube

51. bodys, 52. first bendings, 53. second bendings, 54. the 3rd bendings, 55. steps.

Fig. 4 is the structural representation of base in header

1. header, 11. through holes, 12. platforms, 13. reamings.

Fig. 5 is the structural representation of heating rope

71. heating wire, 72. asbestos cords.

Fig. 6 is the temperature profile of burning optimization on line after welding

Wherein abscissa is time coordinate, and vertical coordinate is temperature coordinate.

Detailed description of the invention

In order to further illustrate technical scheme, further illustrate the specific embodiment party of the present invention in conjunction with accompanying drawing Formula, as in Fig. 3, this example with WGZ670/13.7-12 type boiler, evaporation capacity is 670t/h, superheater steam pressure 13.7MPa, as a example by the supporting high temperature superheater of temperature 540 DEG C imports and exports header, selects diameter 42 millimeters, wall thickness in this example 5.5 millimeters, material is 12Cr1MoV, steel pipe as body 51, selecting the first bending 52 is 150 to the distance of body 51 upper end Millimeter, the lateral separation to the second bending 53 is 80 millimeters, fore-and-aft distance 200 millimeters, selects the second bending 53 to the 3rd bending The lateral separation of 54 is 80 millimeters, and fore-and-aft distance is 200 millimeters, and selecting the 3rd bending 54 is 150 to the distance of body 51 lower end Millimeter, processes the step 55 of a diameter of 41 mm length 20 millimeters, just completes the enforcement of connecting tube 5 at body 51 two ends； Owing to have employed three crooked positions, adding the 4th arm 6 extendable room when expanding with heat and contract with cold, stress is disappeared by these bendings Consumption, without concentrating on the commissure between the 4th arm 6 and header 1, the most just decreases the probability that this weld seam cracks, subtracts Lack header and repaired number of times, improve work efficiency.

As a example by the pipe of a diameter of 42 millimeters of the 4th arm 6 of selection in Fig. 4, this example, selecting base structure is through hole 11 Diameter 30 millimeters, diameter 65 mm depth of reaming 13 is 5 millimeters, and reaming 13 is concentric with through hole 11, reaming 13 and through hole 11 Intersection constitutes platform 12, this completes the enforcement of base in header 1, owing to have employed reaming 13 and platform 12 so that Space even uniform is welded, it is ensured that weld strength and stress are uniform between 4th arm 6 and header 1.

As Fig. 5, this example selected the heating wire of commercially available electric blanket as heating wire 71, select diameter 4-5 millimeter Asbestos cord 72, as asbestos cord 72, is closely wrapped in the outside of heating wire 71, forms the enforcement of heating rope by asbestos cord uniformly, Due to the spatial complex between arm and header 1, using heating rope can preferably adapt to the covering of zones of different, heating is all Even；Owing to have employed heating wire 71 as thermal source, it is possible to control heating curves and heating-up temperature easily.

As in Fig. 2, this example with WGZ670/13.7-12 type boiler, evaporation capacity is 670t/h, superheater steam pressure 13.7MPa, as a example by the supporting high temperature superheater of temperature 540 DEG C imports and exports header, by the 4th arm 6 from root resection length 700 millimeters, the mouth of pipe of remaining 4th arm 6 is made groove and is beneficial to welding, by the junction of the 4th arm 6 in header 1 Base, produce aforementioned structure and shape, the platform 12 that connecting tube 5 one end and base are alignd and concentric with through hole 11, By the other end and the mouth of pipe docking of the 4th arm 6 remainder of connecting tube 5, welding, butt weld uses complete manual argon Weldering weldering welding；Welding current 110-120A；Arm bank of tubes imports and exports header welding with high temperature superheater, uses plug-in type, fillet welding Seam ground floor bottom argon arc welding welding method, single face welding and double face shaping, welding current 110-125A, second and third layer R317 Welding rod, Ф 3.2mm；Second layer electric current 105-110A, third layer electric current 108-1103A；Use welding machine is ZX7-400S, striking side Formula is high-frequency arc strike, and argon arc welding is 160 types model, torch neck a diameter of Ф 10mm, and argon flow amount is 8-10ml, argon arc welding Electrode uses cerium crow extremely rod to be Ф 2.5mm, and welding wire model is R31, and gage of wire is 2.5mm；So ensure that weld seam is heated Uniformly, it is connected firmly.

Such as Fig. 6, heating rope is respectively wound around header 1 and the 4th arm 6 and the outside of connecting tube 5, switches on power and control Device processed, uses high tempering to carry out burning optimization on line；Temperature 730 ± 10 DEG C. warming and cooling rate: 125 DEG C/h；Constant temperature Time: 210 minutes;In temperature-fall period, temperature can not control below 300 DEG C；Overall process automatically dotting record, the completeest Become elimination welding stress, it is ensured that the work of welding quality.It was verified that the 4th arm 6 after the method is repaired, do not have The defects such as the weld cracking that is similar to occurred again.

Claims (1)

1. high temperature superheater imports and exports a restorative procedure for header, comprises the following steps: 1, by the 4th arm from header root Portion excises to arm straight line portion；2, in header, welding bore is made；3, connecting tube is changed；4, connecting tube is welded to header And between arm remainder；5, the part that butt welding is taken over carries out burning optimization on line；Described step 1 is that employing instrument is by interface There is the arm of crackle at place, cuts off at header, is then cut off from the straight line portion of the 4th arm by the other end of arm, and takes Under；Described step 2 is at original header the 4th tube socket, re-works the butt hole of branched pipe；Described step Rapid 3 is by the part of the 4th arm removed, and uses the connecting tube of new construction to be replaced；Described step 4 is newly to tie Between branch holder and the 4th arm of residue that the connecting tube of structure is welded in header；Described step 5 is by connecting tube and collection Case and original 4th arm straight line portion weld and near zone carry out heat treatment, to eliminate stress；It is characterized in that: institute The welding bore stated is arranged at original 4th arm of header and header welding, for stepped ramp type hole, including through hole, and platform, Reaming；Described through hole and header internal run-through；Described platform is vertical with through hole, for circular and concentric with through hole；Described Reaming is arranged on platform, concentric with through hole；Wherein a diameter of 65mm of reaming, hole depth is 4-5mm.