A high-strain welded steel pipe for marine use based on a dual-phase structure and its preparation method

A dual-phase structure and welded steel pipe technology, which is applied in the field of welded steel pipe manufacturing, can solve the problems of large influence on material properties and poor quality stability, and achieve small influence of strain aging, small deviation of outer diameter and out-of-roundness, and high diameter accuracy Effect

Active Publication Date: 2020-09-04
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the use of this molding manufacturing method has a great impact on the material properties, and the quality stability is relatively poor
There is also a preparation method of UOE welded pipe, which is only suitable for the manufacture of ordinary steel pipes with a wall thickness of 10.0-18.0mm

Method used

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  • A high-strain welded steel pipe for marine use based on a dual-phase structure and its preparation method
  • A high-strain welded steel pipe for marine use based on a dual-phase structure and its preparation method
  • A high-strain welded steel pipe for marine use based on a dual-phase structure and its preparation method

Examples

Experimental program
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Effect test

Embodiment

[0071] Take Φ559×31.8mm L485MO UOE straight seam submerged arc welded steel pipe as an example.

[0072] 1. Determination of steel plate structure type: select a wide and thick steel plate with polygonal ferrite (PF) + bainite (B) dual-phase structure, and the phase ratio of PF and B is 1.50-1.63.

[0073] 2. Chemical composition of the steel plate: The mass percentage of the chemical composition of the wide and thick steel plate is 0.046% carbon, 0.18% silicon, 1.74% manganese, 0.0012% sulfur, 0.0062% phosphorus, 0.13% chromium, 0.22% nickel, 0.12% molybdenum, copper 0.18%, niobium+vanadium+titanium≤0.12%, boron 0.0002%, aluminum 0.0028%, nitrogen 0.0038%, the rest is iron and residual impurity elements, cold crack sensitivity index Pcm≤0.17%.

[0074] 3. Steel grade and specification: The steel grade of the wide and thick steel plate used is L485MO, and the thickness is 31.8mm. Considering the amount of deformation during the forming process and the processing allowance of ...

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Abstract

The invention discloses a marine high-strain welded steel pipe based on a double-phase structure and a preparing method thereof. The marine high-strain welded steel pipe is made by a wide and thick steel plate having the double-phase structure, the steel grade of the high-strain welded steel pipe is L485MO, the thickness is larger than or equal to 25.4mm, the width of the steel plate is pi(1-epsilon)D-2t, D refers to the outer diameter of the steel pipe, t refers to wall thickness, epsilon refers to a cold expanding rate, the radius-to-thickness ratio is smaller than or equal to 30, the yield-to-strength ratio Rt0.5 / Rm is smaller than or equal to 0.85, A is larger than or equal to 25%, and UEL is larger than or equal to 7%. The manufactured steel pipe has the characteristics of high strength, high tenacity, high strain capability, low yield-to-strength ratio, low strain aging influence, H2S corrosion resistance, large wall thickness, small radius-thickness ratio, high diameter precision, small outer diameter error and small out-of-roundness error, can fully meet the technical requirements of marine service on the high-strain thick-walled delivery steel pipe, can be used for deep-sea oil and gas exploitation and saves marine development cost.

Description

technical field [0001] The invention belongs to the technical field of welded steel pipe manufacturing, and in particular relates to a high-strain welded steel pipe for marine use based on a dual-phase structure and a preparation method thereof. Background technique [0002] Offshore oil and gas resources are very rich. However, the exploitation of offshore oil and gas resources mainly depends on the development, control and application of key deep-sea technologies and equipment by various countries, one of which is the offshore oil and gas pipeline. [0003] The installation, operation and maintenance of offshore oil and gas pipelines are very different from those on land, and are more difficult than land pipelines. One is that during the laying process of the ocean pipeline, it needs to withstand a large deformation after being connected by girth welding on the pipe-laying ship and then put into the ocean; The third is that the oil and gas extracted from the sea have not...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23P15/00B23K9/18C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/54C22C38/58
CPCB23K9/18B23P15/00C22C38/001C22C38/002C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/54C22C38/58
Inventor 何小东霍春勇马秋荣吉玲康李为卫池强
Owner BC P INC CHINA NAT PETROLEUM CORP
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