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A method for welding anti-corrosion steel pipeline without internal repair

A technology of steel pipe and joint repair, which is applied in the field of anti-corrosion steel pipe without internal repair welding, can solve the problems of root weld bead pollution, influence on corrosion resistance, complicated process, etc., reduce the difficulty of joint welding, improve welding quality, Guaranteed effect of corrosion resistance

Inactive Publication Date: 2016-03-23
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that, first of all, the technical process is more complicated, and it is difficult to guarantee the bonding strength between the lining and the pipe body
Secondly, this method makes the butt joint welding process of pipes into the welding of metal composite pipes, which inevitably introduces new welding problems. Directly opening V-shaped grooves is easy to burn through due to the thin thickness of the inner lining, and when priming The matrix is ​​easy to pollute the bottom weld bead
The Chinese Patent Publication No. CN202419038U also provides a pipeline liner corrosion-resistant alloy internal anti-corrosion filling technology, but this technology has similar problems with the above-mentioned method. The gap between the pipes will have an adverse effect on the butt joint welding
The two patents with Chinese patent publication numbers CN201615318U and CN2804559Y respectively provide a method for eliminating the internal filling step by setting a connecting sleeve, an anti-corrosion sleeve, and a heat-insulating sleeve, but the process of these two methods is relatively complicated, and the anti-corrosion sleeve and The connection between the tube base is not firm
Chinese Patent Publication No. CN102003581A provides a method for eliminating internal joints after welding by providing a connecting part at the end of the pipe. The connecting part of this method needs to be realized by upsetting or casting the pipe, and When the pipes are butt-jointed, the anti-corrosion layer on the end face of the connection part is in physical contact, and there are unavoidable gaps, which affect the corrosion resistance

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  • A method for welding anti-corrosion steel pipeline without internal repair
  • A method for welding anti-corrosion steel pipeline without internal repair
  • A method for welding anti-corrosion steel pipeline without internal repair

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Embodiment 1

[0033] The invention provides a welding method for steel pipelines without internal repairing, and its specific implementation steps are as follows:

[0034] (1) Surfacing steps

[0035] A certain distance b from the inner wall of the steel pipe to the end is 5mm, and a groove with a depth t of 1mm and a length of 20mm is machined in advance, and the two ends of the groove are rounded to prevent unfused defects. Surfacing a certain thickness of corrosion-resistant alloy material on the groove, such as stainless steel or nickel-based alloy welding wire, etc., the welding method adopts argon tungsten arc welding, and the thickness of the surfacing layer should be greater than the depth of the groove to ensure that the weld metal will cover the groove fill up.

[0036] (2) Machining steps

[0037] After the surfacing is completed, the pipe end is machined into a V-shaped butt joint groove. After the machining, the length of the remaining surfacing layer should be 19 mm, and the...

Embodiment 2

[0043] The invention provides a welding method for steel pipelines without internal repairing, and its specific implementation steps are as follows:

[0044] (1) Surfacing steps

[0045] A certain distance b from the inner wall of the steel pipe to the end is 15mm, and a groove with a depth t of 4mm and a length of 40mm is machined in advance, and the two ends of the groove are rounded to prevent unfused defects. Surfacing a certain thickness of corrosion-resistant alloy material on the groove, such as stainless steel or nickel-based alloy welding wire, etc., the welding method adopts argon tungsten arc welding, and the thickness of the surfacing layer should be greater than the depth of the groove to ensure that the weld metal will cover the groove fill up.

[0046] (2) Machining steps

[0047] After the surfacing is completed, the pipe end is machined into a V-shaped butt joint groove. After machining, the length of the remaining surfacing layer should be 35 mm, and the su...

Embodiment 3

[0053] In the Q245R carbon steel pipe with a pipe diameter of Φ76mm and a wall thickness of 9mm, a groove with a length of 22mm and a depth of 2mm is opened at a distance of 10mm from the pipe end, and a corrosion-resistant alloy is surfacing on the groove by argon tungsten arc welding , The filling material can choose 316L or 625 nickel-based alloy welding wire to ensure that the filling metal will fill the groove. The end of the pipe body after surfacing is processed with a V-shaped groove, the groove angle is 40°, the length of the remaining surfacing layer after machining is 20mm, and the transition between the surfacing layer and the inner wall of the pipe is smooth. Spray a layer of 2mm thick polyethylene powder coating on the inner wall of the steel pipe, and the coating covers 10mm of the surfacing metal. The two steel pipes whose inner walls have been sprayed with anti-corrosion coating are butt-connected, and spot-fixed along the circumference of the groove, and a sp...

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Abstract

The invention provides a method for welding an anticorrosion steel pipeline with no internal repaired mouth, which is applicable to the anticorrosion treatment of a steel pipeline welding connector with an anticorrosion coating in the petroleum industry and the chemical industry. The method is characterized in that a groove with a certain length and depth is machined on a position which is at a certain distance from the end part of the steel pipe, an anticorrosion alloy material is surfaced on the groove, the end part of the surfaced steel pipe is machined into a V-shaped groove, an anticorrosion coating with sufficient thickness is coated on the inner wall of the steel pipe, the anticorrosion coating covers sufficient length of the anticorrosion alloy surfacing layer, then two steel pipes are in butt connection with each other, layering welding is carried out after the two steel pipes are fixed on one point, an argon tungsten-arc welding method is adopted, the anticorrosion alloy material which is identical to that of the surfacing is selected as the filling material, and argon is filled into the pipe to protect the pipe in the welding process. Due to the adoption of the novel technology for welding the anticorrosion steel pipeline with no internal repaired mouth, the corrosion resistance of the inner wall and a weld mouth of the pipeline can be guaranteed, the internal mouth repairing technology on the spot after the welding can be avoided, characteristics such as simplicity in construction and reliability in performance can be realized, and the method is suitable for the real engineering application of the petroleum and chemical industry fields.

Description

technical field [0001] The invention relates to the technical field of pipeline welding, in particular to a method for internal repair welding of anticorrosion steel pipelines. Background technique [0002] Most domestic oil and gas fields contain CO 2 、H 2 S and other corrosive media can easily lead to pipeline corrosion during oil and gas gathering and transportation, causing leakage accidents. Generally, steel pipelines in petroleum, chemical and other fields need internal and external anti-corrosion to improve their corrosion resistance, prolong the service life of pipelines, and reduce the occurrence of leakage accidents. Generally, the operation of spraying organic or inorganic anti-corrosion coatings is prefabricated in the factory and then welded on site to grow the pipeline. Due to the high temperature process of butt welding, the anti-corrosion coating near the weld is likely to fail. It is necessary to re-coat the anti-corrosion coating on the inner wall weld a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23P15/00B23K9/04B23K9/16
Inventor 吕世雄徐永强黄永宪崔庆龙郑传奇王龙江
Owner HARBIN INST OF TECH
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