Duplex stainless steel and method for producing same

A technology of duplex stainless steel and manufacturing method, which is applied in the direction of manufacturing tools, furnaces, heat treatment equipment, etc., to achieve the effect of cheap manufacturing and excellent resistance to carbon dioxide gas corrosion

Active Publication Date: 2019-08-23
JFE STEEL CORP
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  • 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 a maximum level

Method used

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

Examples

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Embodiment

[0125] Hereinafter, the present invention will be described by way of examples. In addition, this invention is not limited to the following Example.

[0126] In this example, the molten steel with the composition shown in Table 1 was smelted using a converter, cast into a billet (steel pipe raw material) by continuous casting, and the steel pipe raw material was heated at 1150 to 1250°C, and then, by using a heating model The hot working of the seamless rolling mill was performed to produce a seamless steel pipe having an outer diameter of 83.8 mm x a wall thickness of 12.7 mm. It should be noted that the seamless steel pipe was air-cooled after the pipe production.

[0127] 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

The present invention provides a duplex stainless steel having excellent corrosion resistance, which has excellent carbon dioxide gas corrosion resistance, excellent sulfide stress corrosion crackingresistance and excellent sulfide stress cracking resistance at the same time. This duplex stainless steel has a composition which contains, in mass%, 0.03% or less of C, 1.0% or less of Si, 0.10-1.5%of Mn, 0.030% or less of P, 0.005% or less of S, 20.0-30.0% of Cr, 5.0-10.0% of Ni, 2.0-5.0% of Mo, 2.0-6.0% of Cu, less than 0.07% of N, and one or more elements selected from among 0.05-1.0% of Al,0.02-1.0% of Ti and 0.02-1.0% of Nb, with the balance made up of Fe and unavoidable impurities. This duplex stainless steel has a structure that comprises, in volume percentage, 20-70% of an austenitephase and 30-80% of a ferrite phase.

Description

technical field [0001] The present invention relates to a duplex stainless steel suitable for use in oil wells and gas wells of crude oil or natural gas (hereinafter also simply referred to as oil wells) and a method for producing the same. The duplex stainless steel of the present invention can be suitable for use as a suitable stainless steel seamless steel pipe for oil wells, which has high strength 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 high temperature sulfide stress corrosion cracking resistance (SCC resistance) and sulfide stress cracking resistance (SSC resistance) at room temperature, respectively. 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...

Claims

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Application Information

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IPC IPC(8): C22C38/00C22C38/60C21D6/00C21D8/10C21D9/08C22C38/50
CPCC21D9/08C22C38/50C22C38/60C22C38/001C22C38/004C22C38/02C22C38/04C22C38/42C22C38/44C22C38/46C22C38/48C22C38/52C22C38/54C21D6/004C21D8/105C21D2211/001C21D2211/005C21D6/008C21D9/085C22C38/06
Inventor 江口健一郎柚贺正雄
Owner JFE STEEL CORP
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