Ring welding method for corrosion-resistant alloy lining composite pipe

Abstract

The invention discloses a circumferential welding method for corrosion-resistant alloy-lined composite pipe, which comprises the following steps: (1) cutting a V-shaped groove at the end of the composite pipe to be welded, butting the V-shaped groove at the end of the composite pipe to be welded with a butt joint, wherein the end-to-end gap of the pipe is 0-1.5mm; (2) welding the corrosion-resistant alloy layer by TIG welding to form a cladding weld; (3) Cold spraying is adopted to form the weld seam of the transition layer, the height of the transition layer is not lower than the bimetallic joint surface of the composite pipe, and the thickness of the weld seam of the transition layer is controlled at 0.2-3mm; 4) that base lay is welded by mel electrode gas shielded welding or manual arcwelding to form a base lay weld; As that transition lay adopts the cold spray technology, the metal is sprayed on the surface of the corrosion-resistant alloy and then solidified rapidly, thereby effectively solving the problems that a large amount of coat alloy elements generated by the traditional transition layer welding are punched, mixed and diffused to the transition layer, thereby generating a high-hardness phase and cracks easy to occur in subsequent welding, and playing a better isolation effect.

Description

Technical field: [0001] The invention relates to the technical field of layered bimetallic welding, in particular to a ring welding method for a corrosion-resistant alloy-lined composite pipe. Background technique: [0002] With the increasing demand for energy, the exploitation of oil and gas in harsh corrosive environments has also gradually increased, and the problem of pipeline corrosion has become particularly prominent. Traditional single anti-corrosion technologies such as adding corrosion inhibitors, using plastic inner coatings and using non-metallic pipes, etc. , It has been difficult to meet the needs in terms of corrosion resistance, reliability and economic indicators. The stainless steel inner composite pipe makes full use of the low price of carbon steel, good comprehensive mechanical properties and excellent corrosion resistance of stainless steel, which not only meets the service environment of severe corrosion conditions, but also saves a lot of precious me...

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Problems solved by technology

[0004] The Chinese invention patent published on October 2, 2013 with the publication number CN 103331327 A, the patent name is a bimetal composite pipe girth weld welding method, which uses micro-carbon pure iron welding consumables for transition layer weld welding, The pure iron transition layer can reduce the probability of cracks to a certain extent, but it cannot avoid the diffusion of alloying elements into the transition layer, thus forming high hardness phases.

[0005] The Chinese invention patent published on April 8, 2015 with the publication number CN 104493330 A, the patent name is a bimetal composite pipe girth weld butt welding method, which introduces a high temperature resistant Although the non-melting layer can effectively prevent the diffusion of alloying elements to the base layer, the fluidity of the high-temperature-resistant non-melting layer is poor, and the transition layer and the cladding layer are prone to non-fusion, and the mechanical properties of the high-temperature resistant layer itself are poor, and it is difficult to meet the requirements of the pipeline. steel requirements

[0006] The Chinese invention patent published on January 15, 2016 with the publication number CN 106975819 A, the patent name is a nickel-based bimetallic composite pipe full-position automatic welding method, the method makes a V-shaped groove on the composite pipe, all of which are made of stainless steel The welding wire is used to weld the welding seam of cladding layer, transition layer and base layer. This method can effectively avoid the occurrence of transition layer cracks and non-fusion, but the comprehensive mechanical properties of the base layer weld are difficult to guarantee, and because all welds are made of stainless steel wire, the welding cost is relatively high. high

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