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Method for welding thin layer iron nickel base alloy carbon steel composite tube

An iron-nickel-based alloy, welding method technology, applied in welding medium, welding equipment, welding equipment and other directions, can solve problems such as incompatibility, changes in metallographic structure and chemical composition, cracks, etc., to improve welding quality and avoid defects The formation of the structure, the effect of good corrosion resistance

Active Publication Date: 2009-06-24
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a thin-wall composite pipe girth weld welding method with iron-nickel-based corrosion-resistant alloy or nickel-based alloy material as the inner lining layer and carbon steel base layer, so as to overcome that the existing welding technology is not suitable for inner lining Welding of composite pipes with layer thickness less than 2 mm; repeated heating at the interface between the sealing layer and carbon steel leads to changes in the metallographic structure and chemical composition, resulting in insufficient cracks; welding materials are not suitable for iron-nickel-based corrosion-resistant alloys or Welding of Bimetal Composite Pipe with Nickel-based Alloy as Liner

Method used

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  • Method for welding thin layer iron nickel base alloy carbon steel composite tube
  • Method for welding thin layer iron nickel base alloy carbon steel composite tube
  • Method for welding thin layer iron nickel base alloy carbon steel composite tube

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The relative welding of bimetal composite pipes with an outer diameter of 168 mm is taken as an example to illustrate. The material of the base layer is L360NCS, the thickness of the base layer is 16 mm, the material of the inner lining layer is UNS NO8028, and the thickness of the inner lining layer is 1.5 mm.

[0028] According to the technical scheme of the present invention, it is implemented according to the following steps:

[0029] The specific welding main parameters of Embodiment 1 are shown in Table 1.

[0030] (1) Step processing: A step 3 is processed at the ends of two bimetallic composite pipes to be welded by machining methods (such as figure 1 shown), the width a of the step is twice the wall thickness of the base layer 1, namely 32 millimeters, and the height of the step is three times the thickness of the lining layer 2, namely 4.5 millimeters. After the steps are processed, use a polishing machine to remove the burrs, and use acetone to clean the oi...

Embodiment 2

[0040] The relative welding of bimetal composite pipes with an outer diameter of 114 mm is taken as an example for illustration. The material of the base layer is L360QC, the thickness of the base layer is 12mm, the material of the inner lining layer is UNS NO8825, and the thickness of the inner lining layer is 0.5mm.

[0041] According to the technical scheme of the present invention, it is implemented according to the following steps:

[0042] The main welding parameters are shown in Table 2.

[0043] (1) Step processing: A step 3 is processed at the ends of two bimetallic composite pipes to be welded by machining methods (such as figure 1 shown), the width a of the step is 3 times the thickness of the base layer, that is 36 mm, and the height of the step is 6 times the thickness of the lining layer, that is 3 mm. After the steps are processed, use a polishing machine to remove the burrs, and use acetone to clean the oil stains on the steps.

[0044] (2) Seal welding: sur...

Embodiment 3

[0053] The relative welding of bimetal composite pipes with an outer diameter of 114 mm is taken as an example for illustration. The material of the base layer is L360QC, the thickness of the base layer is 12 mm, the material of the inner lining layer is UNS NO6985, and the thickness of the inner lining layer is 1.0 mm.

[0054] According to the technical scheme of the present invention, it is implemented according to the following steps:

[0055] The main welding parameters are shown in Table 3.

[0056] (1) Step processing: A step 3 is processed at the ends of two bimetallic composite pipes to be welded by machining methods (such as figure 1 shown), the width a of the step is three times the thickness of the base layer, that is, 36 mm, and the height of the step is four times the thickness of the lining layer, that is, 4 mm. After the steps are processed, use a polishing machine to remove the burrs, and use acetone to clean the oil stains on the steps.

[0057] (2) Seal w...

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Abstract

The invention relates to a method for welding a carbon steel composite pipe of a thin iron-nickel-based alloy. The method comprises: processing a step on the end part of the composite pipe; adopting the surfacing of argon arc welding on the surface of the step and trimming the surfacing layer; processing a groove; adopting tungsten electrode argon arc welding to carry out three-point positioning of spot welding evenly around a welding seam, and adopting the tungsten electrode argon arc welding to carry out back welding on the root; and adopting manual electric arc welding to carry out filling welding and overlay welding on the upper part of a second layer of back welding. The chemical compositions of a welding material by weight percentage: 0.02 to 0.1 percent of C, 0.2 to 1.0 percent of Si, 1.0 to 2.2 percent of Mn, 20.0 to 31.5 percent of Cr, 40.0 to 60.0 percent of Ni, 8.0 to 14.5 percent of Mo, 0.5 to 2.5 percent of Cu, 0 to 5.0 percent of Co, 0.3 to 4.2 percent of Nb, and the balance being Fe. The welding seam has the characteristics of no sensitivity to offset, favorable corrosion resistance, high strength and favorable plastic toughness.

Description

technical field [0001] The invention relates to a girth weld welding method of a double-metal composite pipe whose inner lining layer is a thin-walled iron-nickel-based corrosion-resistant alloy and whose base layer is carbon steel. Background technique [0002] In recent years, a bimetal composite pipe composed of carbon steel material as the outer pipe and iron-nickel-based corrosion-resistant alloy material as the inner pipe can effectively solve the problem of high H2 content. 2 S and CO 2 , high Cl content - It has a wide range of uses for the corrosion of oil and gas pipelines in harsh corrosive environments such as organic sulfur. The iron-nickel-based corrosion-resistant alloy in the present invention refers to an alloy material containing more than 30% and less than 55% by weight of nickel. The lining layer is usually made of iron-nickel based corrosion-resistant alloys such as UNS NO8028, UNS NO8825, UNS NO6985. The thickness of the lining layer is usually 0.3 ...

Claims

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Application Information

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IPC IPC(8): B23K9/16B23K9/235B23K35/30B23K9/095B23K101/06
Inventor 魏斌白真权尹成先李发根赵新伟马秋荣冯耀荣
Owner BC P INC CHINA NAT PETROLEUM CORP
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