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Welding method for circumferential weld of thick-wall nickel-based alloy header

A technology of nickel-based alloys and welding methods, which is applied to the welding of deep grooves of nickel-based alloy thick-walled pipes and the welding field of nickel-based alloys, which can solve the problems of high linear expansion coefficient, large shrinkage deformation, and reduced weld performance of nickel-based alloys And other issues

Active Publication Date: 2016-07-13
DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] (1) The fluidity of the nickel-based alloy molten pool is poor, the slag removal is difficult, the heat input is large during the welding process, and the circular seam welding is also prone to produce coarse grains to reduce the performance of the weld, and at the same time, the welding thermal crack is not easy to be controlled;
[0007] (2) The linear expansion coefficient of the nickel-based alloy is high, and the shrinkage deformation is relatively large during the welding process. The existing design of the groove of the circular seam of the header is not suitable for welding of the nickel-based alloy;
[0008] (3) Ni-25Cr-20Co also contains more active elements, which are easily oxidized during welding, so reasonable welding protection methods are required

Method used

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  • Welding method for circumferential weld of thick-wall nickel-based alloy header
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  • Welding method for circumferential weld of thick-wall nickel-based alloy header

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Embodiment 1

[0052] A method for welding the girth weld of a thick-walled nickel-based alloy header according to the present invention, wherein the wall thickness δ of the nickel-based alloy header is 30-150mm, and the method comprises the following steps:

[0053] S1: Selection of welding consumables

[0054] Use homogeneous welding materials: the wire grade is ERNiCrCo-1.

[0055] S2: Selection of welding method

[0056] Hot wire TIG welding is adopted, the thickness of the welding torch is H12mm, the welding head has the function of two-way shielding gas, and the tungsten pole can swing during the welding process.

[0057] S3: Preparation before welding

[0058] Such as figure 1 As shown, respectively measure the wall thickness of the joint of the first nickel-based alloy header cylinder 1 and the second nickel-base alloy header cylinder 2 to be welded, and according to the difference between the two wall thicknesses, the two nickel-based alloy header cylinders The inner wall of the...

Embodiment 2

[0074] The specific implementation steps of this embodiment are roughly the same as those of Embodiment 1, except that step S44: welding, and the welding includes the following sub-steps:

[0075] S441: Back welding, current 160A, voltage 10V, welding speed 80-120mm / min, tungsten electrode does not swing during welding;

[0076] S442: Transition welding, current 200A, voltage 10V, welding speed 90-130mm / min, tungsten electrode swings during welding;

[0077] S443: Filler welding, current 280A, voltage 10V, welding speed 80-120mm / min, tungsten electrode swings during welding;

[0078] S444: Cover welding, current 260A, voltage 10V, welding speed 80-120mm / min, tungsten electrode does not swing during welding.

Embodiment 3

[0080] The specific implementation steps of this embodiment are roughly the same as those of Embodiment 1, except that step S44: welding, and the welding includes the following sub-steps:

[0081] S441: bottom welding, current 200A, voltage 10V, welding speed 80-120mm / min, tungsten electrode does not swing during welding;

[0082] S442: Transition welding, current 240A, voltage 10V, welding speed 90-130mm / min, tungsten swing during welding;

[0083] S443: Filler welding, current 320A, voltage 10V, welding speed 80-120mm / min, tungsten electrode swings during welding;

[0084] S444: Cover welding, current 300A, voltage 10V, welding speed 80-120mm / min, tungsten electrode does not swing during welding.

[0085] The selection of the welding parameter of step S44 among the table 4. embodiment 1-3

[0086]

[0087] In the above three embodiments, when the bottom welding current is 180A, the excess welding current is 220A, the filling welding current is 300A, and the cover weldin...

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Abstract

The invention relates to the technical field of welding of nickel-based alloys, and discloses a welding method for a circumferential weld of a thick-wall nickel-based alloy header. The welding method mainly comprises the following steps: welding material selection, welding mode selection, preparation before welding and construction of welding. The welding mode adopts hot wire TIG welding; a welding head has a double-path protection gas function; preparation before welding comprises preparation of a groove, and the welding process comprises spot welding, backing welding, transitional welding, filling welding and cosmetic welding. Aiming at the problem of the conventional nickel-based alloy welding, the invention provides a welding method suitable for circumferential welds of the Ni-25Cr-20Co thick-wall nickel-based alloy header.

Description

technical field [0001] The invention relates to the welding of nickel-based alloys, in particular to the welding of deep grooves of nickel-based alloy thick-walled pipes used for boiler headers, and belongs to the field of welding technology and engineering. Background technique [0002] The header is one of the key components of the boiler, and its main function is to collect and mix working fluids, eliminate or reduce thermal deviation and redistribute working fluids. The header is composed of header body, end cap, pipe joint, lug plate and body accessories. Most of the header body is made of thick-walled tubes with larger diameter butt ring welding, and its material is the same as that of the boiler heating surface. unanimous. [0003] With the improvement of boiler design parameters, the grade of materials used in the high temperature section will continue to increase, especially nickel-based alloys in 700 °C boilers will be widely used. Although nickel-based alloy wel...

Claims

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Application Information

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IPC IPC(8): B23K9/167B23K9/235B23K9/095B23K35/30
CPCB23K9/095B23K9/167B23K9/235B23K35/304
Inventor 王林森王冬平钟正彬陈舟刘洪伟
Owner DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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