Martensitic stainless steel seamless pipe for oil country tubular goods, and method for manufacturing same
a technology of martensitic stainless steel and seamless pipes, which is applied in the direction of manufacturing tools, furnaces, heat treatment equipment, etc., can solve the problem that the steels described in these patent applications have the level of achieve excellent sulfide stress corrosion cracking resistance (ssc resistance), the effect of high strength
Inactive Publication Date: 2020-12-31
JFE STEEL CORP
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Benefits of technology
The present invention provides a martensitic stainless steel seamless pipe for oil country tubular goods with excellent sulfide stress corrosion cracking resistance and high strength. The steel has a composition and quenching and tempering process that meet specific ranges and requirements. It can withstand high levels of stress and is resistant to corrosion in environments with high levels of carbon dioxide, chloride, and sulfide ions.
Problems solved by technology
However, these patent applications do not take into account sulfide stress corrosion cracking resistance in other atmospheres, and it cannot be said that the steels described in these patent applications have the level of sulfide stress corrosion cracking resistance that can withstand the today's ever demanding severe corrosive environments.
Method used
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examples
[0056]The present invention is further described below through Examples.
[0057]Molten steels containing the components shown in Table 1 were made into steel with a converter, and cast into billets (steel pipe material) by continuous casting. The billet was hot worked into a pipe with a model seamless rolling mill, and cooled by air cooling or water cooling to produce a seamless steel pipe measuring 83.8 mm in outer diameter and 12.7 mm in wall thickness.
[0058]Each seamless steel pipe was cut to obtain a test material, which was then subjected to quenching and tempering under the conditions shown in Table 2. A test piece for microstructure observation was taken from the quenched and tempered test material. After polishing, the amount of retained austenite (γ) was measured by X-ray diffractometry.
[0059]Specifically, the amount of retained austenite was found by measuring the diffraction X-ray integral intensities of the γ (220) plane and the α (211) plane. The results were then convert...
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Abstract
The invention provides a martensitic stainless steel seamless pipe for oil country tubular goods having a yield stress of 758 MPa (110 ksi) or more, and excellent sulfide stress corrosion cracking resistance and a method for manufacturing the same. The martensitic stainless steel seamless pipe for oil country tubular goods having a yield stress of 758 MPa or more has a composition that contains, in mass %, C: 0.010% or more, Si: 0.5% or less, Mn: 0.05 to 0.24%, P: 0.030% or less, S: 0.005% or less, Ni: 4.6 to 8.0%, Cr: 10.0 to 14.0%, Mo: 1.0 to 2.7%, Al: 0.1% or less, V: 0.005 to 0.2%, N: 0.1% or less, Ti: 0.06 to 0.25%, Cu: 0.01 to 1.0%, and Co: 0.01 to 1.0%, in which C, Mn, Cr, Cu, Ni, Mo, W, Nb, N, and Ti satisfy the predetermined relations, and the balance is Fe and incidental impurities.
Description
CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is the U.S. National Phase application of PCT / JP2018 / 032685, filed Sep. 4, 2018, which claims priority to Japanese Patent Application No. 2017-190075, filed Sep. 29, 2017, the disclosures of each of these applications being incorporated herein by reference in their entireties for all purposes.FIELD OF THE INVENTION[0002]The present invention relates to a martensitic stainless steel seamless pipe for oil country tubular goods for use in crude oil well and natural gas well applications (hereinafter, referred to simply as “oil country tubular goods”), and to a method for manufacturing such a martensitic stainless steel seamless pipe. Particularly, the invention relates to a seamless steel pipe for oil country tubular goods having a yield stress YS of 758 MPa or more, and excellent sulfide stress corrosion cracking resistance (SSC resistance) in a hydrogen sulfide (H2S)-containing environment, and to a method for manufacturing such a sea...
Claims
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IPC IPC(8): C21D9/08C21D1/22C22C38/48C22C38/00C22C38/44C22C38/06C21D8/10C22C38/50C22C38/42C22C38/46C22C38/02C22C38/52
CPCC21D9/085C21D8/105C22C38/50C22C38/002C22C38/02C21D2211/008C22C38/52C22C38/42C22C38/44C22C38/46C22C38/001C22C38/06C21D1/22C22C38/48C21D9/08C22C38/00C22C38/54C22C38/04C22C38/005C21D8/10
Inventor ENDO, MAMIKAMO, YUICHIYUGA, MASAO
Owner JFE STEEL CORP