Duplex stainless steel pipe used under marine environment and machining method of duplex stainless steel pipe

A duplex stainless steel, marine environment technology, applied in the field of transportation pipelines, can solve the problems of ecological environment damage and short service life

Inactive Publication Date: 2020-06-05
WUXI XINFENG TUBE IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Once a leak occurs, it will cause immeasurable losses and great damage to the ecological environment. The service life of the existing products on the market for oil and gas pipelines in the ocean is generally not long, and it takes a lot of manpower and material resources to replace the pipeline. Therefore, it is urgently needed. A pipeline with stable performance and more corrosion resistance to seawater and oil gas

Method used

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  • Duplex stainless steel pipe used under marine environment and machining method of duplex stainless steel pipe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Embodiment 1: The duplex stainless steel pipe in the marine environment of this embodiment includes a steel pipe formed by integral hot extrusion of the outer duplex stainless steel layer and the inner duplex stainless steel layer, and the outer duplex stainless steel layer is the first ferrite ~Austenitic duplex stainless steel alloy, the specific weight ratio content is:

[0057]C is 0.05%; Si is 0.6%; Mn is 0.04%; Cr is 27%; Ni is 7%; Mo is 0.6%; S is 0.01%; Al is 0.06%; W is 2%; P is 0.03%; Cu is 1.5%; N is 0.2%; the ferrite content is 55%, and the rest is austenite and irremovable impurities; among them, non-metallic inclusions: A≤1.0 level, B, C≤2.0 level, D≤1.5 level; A+B+C+D≤5 level.

[0058] The inner duplex stainless steel layer is the second ferrite-austenite duplex stainless steel alloy, the specific content is:

[0059] C is 0.03%; Si is 0.1%; Mn is 0.06%; Cr is 25%; Ni is 7%; Mo is 1%; S is 0.01%; Al is 0.03%; W is 3%; P is 0.03%; Cu is 2%; N is 0.25%; ...

Embodiment 2

[0076] Embodiment 2: This embodiment is a further improvement on the basis of Embodiment 1. It includes a steel pipe formed by integral hot extrusion of the outer duplex stainless steel layer and the inner duplex stainless steel layer. The outer duplex stainless steel layer is the first Ferritic-austenitic duplex stainless steel alloy, the specific weight ratio content is:

[0077] C is 0.04%; Si is 0.1%; Mn is 0.03%; Cr is 25%; Ni is 5%; Mo is 0.3%; S is 0.008%; Al is 0.03%; W is 1%; P is 0.02%; Cu is 1%; N is 0.18%; the ferrite content is 45%, the rest is austenite and irremovable impurities; among them, non-metallic inclusions: A≤1.0 level, B, C≤2.0 level, D ≤1.5 level; A+B+C+D≤5 level.

[0078] The inner duplex stainless steel layer is the second ferrite-austenite duplex stainless steel alloy, the specific content is:

[0079] C is 0.02%; Si is 0.03%; Mn is 0.03%; Cr is 22%; Ni is 6%; Mo is 0.6%; S is 0.008%; Al is 0.02%; W is 2%; P is 0.02%; Cu is 1.5%; N is 0.2%; ferr...

Embodiment 3

[0080] Embodiment 3: This embodiment is a further improvement on the basis of Embodiment 1, including a steel pipe formed by integral hot extrusion of the outer duplex stainless steel layer and the inner duplex stainless steel layer, and the outer duplex stainless steel layer is the first Ferritic-austenitic duplex stainless steel alloy, the specific weight ratio content is:

[0081] C is 0.045%; Si is 0.4%; Mn is 0.035%; Cr is 26%; Ni is 6%; Mo is 0.5%; S is 0.007%; Al is 0.045%; W is 1.5%; P is 0.025%; Cu is 1.3%; N is 0.19%; the ferrite content is 50%, the rest is austenite and irremovable impurities; among them, non-metallic inclusions: A≤1.0 level, B, C≤2.0 level, D ≤1.5 level; A+B+C+D≤5 level.

[0082] The inner duplex stainless steel layer is the second ferrite-austenite duplex stainless steel alloy, the specific content is:

[0083] C is 0.025%; Si is 0.07%; Mn is 0.05%; Cr is 24%; Ni is 6.5%; Mo is 0.8%; S is 0.009%; Al is 0.025%; W is 2.5%; P is 0.025%; Cu is 1.8%...

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Abstract

The invention discloses a duplex stainless steel pipe used under a marine environment and a machining method of the duplex stainless steel pipe. The special process of a composite pipe is adopted, a pipeline material of the composite pipe is divided into two layers, the outer layer is made of a material specially prepared for seawater corrosion resistance, the inner layer is made of a material specially prepared for resistance to corrosion of hydrogen sulfide, hydrogen and other oil gas substances, the outer layer and the inner layer are subjected to machining, heat treatment and extrusion into a whole, the structure strength, machinability and weldability of the composite pipe are further emphasized in the material formula, and the composite pipe with a certain difference formed between the materials of the inner layer and the outer layer is formed. The toughness of the inner duplex stainless steel layer is higher than that of the outer duplex stainless steel layer, the rigidity of the outer duplex stainless steel layer is higher than that of the inner duplex stainless steel layer, by controlling the alloy ratio of the inner duplex stainless steel layer to the outer duplex stainless steel layer, the inner duplex stainless steel layer is more resistant to hydrogen sulfide corrosion and has higher hydrogen brittleness resistance, and the outer duplex stainless steel layer has higher seawater corrosion resistance and better impact resistance.

Description

technical field [0001] The invention relates to the technical field of transportation pipelines, in particular to a duplex stainless steel pipe in a marine environment. Background technique [0002] At present, my country's future national economic and social development plan has emphasized the need to "strengthen marine awareness, safeguard marine rights and interests, protect marine ecology, develop marine resources, implement comprehensive marine management, and promote marine economic development"; "National Medium and Long-Term Science and Technology Development The Planning Outline lists ocean as one of the five national key strategic areas for advanced deployment. However, in the development of marine resources and the protection of rights and interests, all kinds of marine equipment and facilities constructed and used, such as offshore platforms, oil and gas exploration and storage and transportation, marine power and other facilities, as well as ships and warships, a...

Claims

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Application Information

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IPC IPC(8): B23P15/00F16L9/04F16L57/02F16L57/06F16L58/08
CPCB23P15/00F16L9/04F16L57/02F16L57/06F16L58/08
Inventor 张秀杰冷俊祎李峰
Owner WUXI XINFENG TUBE IND
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