Duplex stainless steel and method for manufacturing same

A technology of duplex stainless steel, manufacturing method, applied in the direction of manufacturing tools, furnace types, furnaces, etc.

Active Publication Date: 2019-04-16
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, in the technology described in Patent Document 1, the yield strength can only reach the highest level of about 80 ksi (551 MPa), and there is a problem that it can only be applied to some steel pipes as oil country tubular goods.

Method used

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  • Duplex stainless steel and method for manufacturing same
  • Duplex stainless steel and method for manufacturing same
  • Duplex stainless steel and method for manufacturing same

Examples

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Embodiment

[0153] Hereinafter, the present invention will be described by way of examples. In addition, this invention is not limited to the following Example.

[0154] The molten steel with the composition shown in Table 1 was smelted in a converter, cast into a slab (steel pipe raw material) by a continuous casting method, and the steel pipe raw material was heated at 1150 to 1250°C, and then heated by using a heating model seamless rolling machine. Hot working was performed to form a seamless steel pipe having an outer diameter of 83.8 mm x a wall thickness of 12.7 mm. In addition, air cooling was performed after tube manufacturing.

[0155] The obtained seamless steel pipes were subjected to a solution heat treatment in which heating was performed under the conditions shown in Table 2, followed by cooling. Then, an aging heat treatment of heating under the conditions shown in Table 2 and then air cooling was further performed.

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Abstract

Provided is a duplex stainless steel having excellent corrosion resistance, in which excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance are provided at the same time. The present invention has a composition containing, in terms of mass%, 0.03% or less of C, 1.0% or less of Si, 0.10-1.5% Mn, 0.030%or less of P, 0.005% or less of S, 20.0-30.0% Cr, 5.0-10.0% Ni, 2.0-5.0% Mo, 2.0-6.0% Cu, and less than 0.07% of N, the remainder comprising Fe and unavoidable impurities, and the metallographic structure of the present invention has an austenitic phase that is 20-70% by volume ratio and a ferritic phase that is 30-80% by volume ratio.

Description

technical field [0001] The present invention relates to a duplex stainless steel suitable for use in crude oil or natural gas oil wells, gas wells, and the like, and a manufacturing method thereof. The duplex stainless steel of the present invention can be suitable for use as a suitable stainless steel seamless steel pipe for oil well applications, which has high strength, high toughness and corrosion resistance, especially in the presence of carbon dioxide gas (CO 2 ) and chloride ions (Cl - ) and high temperature extremely severe corrosion resistance to carbon dioxide gas corrosion, and hydrogen sulfide (H 2 S) is excellent in low temperature sulfide stress corrosion cracking resistance (SCC resistance) and normal temperature sulfide stress cracking resistance (SSC resistance). Background technique [0002] In recent years, from the standpoint of rising crude oil prices and the prospect of depletion of oil resources in the near future, deep oil fields that cannot be igno...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C21D8/10C21D9/08C22C38/44C22C38/60
CPCC22C38/44C22C38/60C21D6/004C21D6/005C21D6/008C21D8/105C22C38/001C22C38/002C22C38/004C22C38/005C22C38/008C22C38/02C22C38/04C22C38/42C22C38/46C22C38/48C22C38/50C22C38/52C22C38/54C21D2211/001C21D2211/005C21D9/08C21D8/10
Inventor 吉村悠佑太田裕树柚贺正雄加茂祐一江口健一郎
Owner JFE STEEL CORP
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