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A thick-walled nickel-based alloy header girth welding method

A nickel-based alloy and welding method technology are applied in the welding of nickel-based alloy thick-walled pipes with deep grooves and the welding of nickel-based alloys. And other issues

Active Publication Date: 2018-04-06
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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  • A thick-walled nickel-based alloy header girth welding method
  • A thick-walled nickel-based alloy header girth welding method
  • A thick-walled nickel-based alloy header girth welding method

Examples

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Embodiment 1

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

[0053] S1: Welding material selection

[0054] Use homogeneous welding materials: ERNiCrCo-1 for welding wire.

[0055] S2: Welding method selection

[0056] Hot wire TIG welding is used, the thickness of the welding gun is 12mm, the welding head has a dual-circuit shielding gas function, and the tungsten electrode can swing during the welding process.

[0057] S3: Preparation before welding

[0058] Such as figure 1 As shown, the wall thicknesses of the butt joints of the first nickel-based alloy header cylinder body 1 and the second nickel-based alloy header cylinder body 2 that need to be welded are measured, and the two nickel-based alloy header cylinders The inner wall of the butt joint of the base alloy header cylinder is machined to remove the margin to e...

Embodiment 2

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

[0075] S441: bottom welding, current 160A, voltage 10V, welding speed 80-120mm / min, the 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: Fill 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, the 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. The welding further includes the following sub-steps:

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

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

[0083] S443: Fill 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, the tungsten electrode does not swing during welding.

[0085] Table 4. Selection of welding parameters in step S44 in embodiment 1-3

[0086]

[0087] In the above three embodiments, when the bottom welding current is 180A, the over welding current is 220A, the fill welding current is 300A, and the cover welding current is 2...

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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 tubes used in 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 a header barrel, end caps, pipe joints, ear plates and barrel accessories. Most of the header barrels are formed by butt butt welded with thick-walled pipes of larger diameter. The material is the same as that of the heating surface of the boiler. Consistent. [0003] With the improvement of boiler design parameters, the grades of materials used in the high-temperature section continue to increase, especially nickel-based alloys in 700 ℃ boilers will be widely used. Although nickel-based ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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