• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention is intended to provide a martensitic stainless steel seamless pipe for oil country tubular goods having high strength, and excellent sulfide stress corrosion cracking resistance. A method for manufacturing such a martensitic stainless steel seamless pipe is also provided. The martensitic stainless steel seamless pipe for oil country tubular goods has a yield stress of 758 MPa or more, and a composition that contains, in mass%, C: 0.0010 to 0.0094%, Si: 0.5% or less, Mn: 0.05 to 0.5%, P: 0.030% or less, S: 0.005% or less, Ni: 4.6 to 7.3%, Cr: 10.0 to 14.5%, Mo: 1.0 to 2.7%, Al : 0.1% or less, V: 0.2% or less, N: 0.1% or less, Ti: 0.01 to 0.50%, 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.
    公开号:EP3690072A1
    申请号:EP18860839.2
    申请日:2018-09-04
    公开日:2020-08-05
    发明作者:Mami Endo；Yuichi Kamo；Masao Yuga
    申请人:JFE Steel Corp；
    IPC主号:C21D9-00
    专利说明:
    [0001] 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 improvement of sulfide stress corrosion cracking resistance (SSC resistance) in a hydrogen sulfide (H2S)-containing environment. Background Art
    [0002] Increasing crude oil prices and an expected shortage of petroleum resources in the near future have prompted active development of oil country tubular goods for use in applications that were unthinkable in the past, for example, such as in deep oil fields, and in oil fields and gas oil fields of severe corrosive environments containing carbon dioxide gas, chlorine ions, and hydrogen sulfide. The material of steel pipes for oil country tubular goods intended for these environments require high strength, and excellent corrosion resistance.
    [0003] Oil country tubular goods used for mining of oil fields and gas fields of an environment containing carbon dioxide gas, chlorine ions, and the like typically use 13% Cr martensitic stainless steel pipes. There has also been global development of oil fields or the like in very severe corrosive environments containing hydrogen sulfide. Accordingly, the need for SSC resistance is high, and there has been increasing use of an improved 13% Cr martensitic stainless steel pipe of a reduced C content and increased Ni and Mo contents.
    [0004] PTL 1 describes a composition using a 13% Cr-base steel as a basic composition, in which C is contained in a much smaller content than in common stainless steels, and Ni, Mo, and Cu are contained so as to satisfy Cr + 2Ni + 1.1Mo + 0.7Cu ≤ 32.5. The composition also contains at least one of Nb: 0.20% or less, and V: 0.20% or less so as to satisfy the condition Nb + V ≥ 0.05%. It is stated in PTL 1 that this will provide high strength with a yield stress of 965 MPa or more, high toughness with a Charpy absorption energy at - 40°C of 50 J or more, and desirable corrosion resistance.
    [0005] PTL 2 describes a 13% Cr-base martensitic stainless steel pipe of a composition containing carbon in an ultra low content of 0.015% or less, and 0.03% or more of Ti. It is stated in PTL 2 that this stainless steel pipe has high strength with a yield stress on the order of 95 ksi, low hardness with an HRC of less than 27, and excellent SSC resistance. PTL 3 describes a martensitic stainless steel that satisfies 6.0 ≤ Ti/C ≤ 10.1, based on the finding that Ti/C has a correlation with a value obtained by subtracting a yield stress from a tensile stress. It is stated in PTL 3 that this technique, with a value of 20.7 MPa or more yielded as the difference between tensile stress and yield stress, can reduce hardness variation that impairs SSC resistance.
    [0006] PTL 4 describes a martensitic stainless steel containing Mo in a limited content of Mo ≥ 2.3-0.89Si + 32.2C, and having a metal microstructure composed mainly of tempered martensite, carbides that have precipitated during tempering, and intermetallic compounds such as a Laves phase and a δ phase formed as fine precipitates during tempering. It is stated in PTL 4 that the steel produced by this technique has high strength with a 0.2% proof stress of 860 MPa or more, and excellent carbon dioxide corrosion resistance and sulfide stress corrosion cracking resistance. Citation ListPatent Literature
    [0007] PTL 1: JP-A-2007-332442 PTL 2: JP-A-2010-242163 PTL 3: WO2008/023702 PTL 4: WO2004/057050Summary of InventionTechnical Problem
    [0008] The development of recent oil fields and gas fields is made in severe corrosive environments containing CO2, Cl-, and H2S. Increasing H2S concentrations due to aging of oil fields and gas fields are also of concern. Steel pipes for oil country tubular goods for use in these environments are therefore required to have excellent sulfide stress corrosion cracking resistance (SSC resistance). However, the technique described in PTL 1, which describes a steel having excellent corrosion resistance against CO2, does not take into account sulfide stress corrosion cracking resistance, and it cannot be said that the steel has corrosion resistance against a severe corrosive environment.
    [0009] PTL 2 states that sulfide stress cracking resistance can be maintained under an applied stress of 655 MPa in an atmosphere of a 5% NaCl aqueous solution (H2S: 0.10 bar) having an adjusted pH of 3.5. The steel described in PTL 3 has sulfide stress cracking resistance in an atmosphere of a 20% NaCl aqueous solution (H2S: 0.03 bar, CO2 bal.) having an adjusted pH of 4.5. The steel described in PTL 4 has sulfide stress cracking resistance in an atmosphere of a 25% NaCl aqueous solution (H2S: 0.03 bar, CO2 bal.) having an adjusted pH of 4.0. 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.
    [0010] It is accordingly an object of the present invention to provide a martensitic stainless steel seamless pipe for oil country tubular goods having high strength and excellent sulfide stress corrosion cracking resistance. The invention is also intended to provide a method for manufacturing such a martensitic stainless steel seamless pipe.
    [0011] As used herein, "high strength" means a yield stress of 758 MPa (110 ksi) or more. The yield stress is preferably 896 MPa or less.
    [0012] As used herein, "excellent sulfide stress corrosion cracking resistance" means that a test piece dipped in a test solution (a 0.165 mass% NaCl aqueous solution; liquid temperature: 25°C; H2S : 1 bar; CO2 bal.) having an adjusted pH of 3.5 with addition of sodium acetate and hydrochloric acid does not crack even after 720 hours under an applied stress equal to 90% of the yield stress. Solution to Problem
    [0013] In order to achieve the foregoing objects, the present inventors conducted intensive studies of the effects of various alloy elements on sulfide stress corrosion cracking resistance (SSC resistance) in a CO2, Cl--, and H2S-containing corrosive environment, using a 13% Cr-base stainless steel pipe as a basic composition. The studies found that a martensitic stainless steel seamless pipe for oil country tubular goods having the desired strength, and excellent SSC resistance in a CO2, Cl--, and H2S-containing corrosive environment, and in an environment under an applied stress close to the yield stress can be provided when the steel components are contained in predetermined ranges, and C, Mn, Cr, Cu, Ni, Mo, W, Nb, N, and Ti are contained in adjusted amounts that satisfy appropriate relations and ranges, and when the steel is subjected to appropriate quenching and tempering.
    [0014] The present invention is based on this finding, and was completed after further studies. Specifically, the gist of the present invention is as follows.[1] A martensitic stainless steel seamless pipe for oil country tubular goods having a yield stress of 758 MPa or more,the martensitic stainless steel seamless pipe comprising, in mass%, C: 0.0010 to 0.0094%, Si: 0.5% or less, Mn: 0.05 to 0.5%, P: 0.030% or less, S: 0.005% or less, Ni: 4.6 to 7.3%, Cr: 10.0 to 14.5%, Mo: 1.0 to 2.7%, Al : 0.1% or less, V: 0.2% or less, N: 0.1% or less, Ti: 0.01 to 0.50%, Cu: 0.01 to 1.0%, and Co: 0.01 to 1.0%, in which the values of the following formulae (1) and (2) satisfy the formulae (3) below, and the balance is Fe and incidental impurities. − 109.37 C + 7.307 Mn + 6.399 Cr + 6.329 Cu + 11.343 Ni − 13.529 Mo + 1.276 W + 2.925 Nb + 196.775 N − 2.621 Ti − 120.307
    [0015] The present invention has enabled production of a martensitic stainless steel seamless pipe for oil country tubular goods having excellent sulfide stress corrosion cracking resistance (SSC resistance) in a CO2, Cl--, and H2S-containing corrosive environment, and high strength with a yield stress YS of 758 MPa (110 ksi) or more. Description of Embodiments
    [0016] The following describes the reasons for specifying the composition of a steel pipe of the present invention. In the following, "%" means percent by mass, unless otherwise specifically stated. C: 0.0010 to 0.0094%
    [0017] C is an important element involved in the strength of the martensitic stainless steel, and is effective at improving strength. C needs to be contained in an amount of 0.0010% or more to obtain the strength desired in the present invention. When contained in an amount of more than 0.0094%, C generates chromium carbonitrides, and impairs the corrosion resistance. For this reason, the C content is limited to 0.0010 to 0.0094% in the present invention. The C content is preferably 0.0050 to 0.0094%. Si: 0.5% or Less
    [0018] Si acts as a deoxidizing agent, and is contained in an amount of desirably 0.05% or more. A Si content of more than 0.5% impairs carbon dioxide corrosion resistance and hot workability. For this reason, the Si content is limited to 0.5% or less. Preferably, the Si content is 0.10 to 0.30%. Mn: 0.05 to 0.5%
    [0019] Mn is an element that improves hot workability, and is contained in an amount of 0. 05% or more to provide the necessary strength. When Mn is contained in an amount of more than 0.5%, the effect becomes saturated, and the cost increases. For this reason, the Mn content is limited to 0.05 to 0.5%. Preferably, the Mn content is 0.4% or less. P: 0.030% or Less
    [0020] P is an element that impairs carbon dioxide corrosion resistance, pitting corrosion resistance, and sulfide stress corrosion cracking resistance, and should desirably be contained in as small an amount as possible in the present invention. However, an excessively small P content increases the manufacturing cost. For this reason, the P content is limited to 0.030% or less, which is a content range that does not cause a severe impairment of characteristics, and that is economically practical in industrial applications. Preferably, the P content is 0.020% or less. S: 0.005% or Less
    [0021] S is an element that seriously impairs hot workability, and should desirably be contained in as small an amount as possible. A reduced S content of 0.005% or less enables pipe production using an ordinary process, and the S content is limited to 0.005% or less in the present invention. Preferably, the S content is 0.003% or less. Ni: 4.6 to 7.3%
    [0022] Ni is an element that increases the strength of the protective coating, and improves the corrosion resistance. Ni also increases steel strength by forming a solid solution. Ni needs to be contained in an amount of 4.6% or more to obtain these effects. With a Ni content of more than 7.3%, the martensite phase becomes less stable, and the strength decreases. For this reason, the Ni content is limited to 4.6 to 7.3%. Cr: 10.0 to 14.5%
    [0023] Cr is an element that forms a protective coating, and improves the corrosion resistance. The required corrosion resistance for oil country tubular goods can be provided when Cr is contained in an amount of 10.0% or more. A Cr content of more than 14.5% facilitates ferrite generation, and a stable martensite phase cannot be provided. For this reason, the Cr content is limited to 10 . 0 to 14 . 5%. Preferably, the Cr content is 11.0 to 13.5%. Mo: 1.0 to 2.7%
    [0024] Mo is an element that improves the resistance against pitting corrosion by Cl-. Mo needs to be contained in an amount of 1.0% or more to obtain the corrosion resistance necessary for a severe corrosive environment. When Mo is contained in an amount of more than 2.7%, the effect becomes saturated. Such a high Mo content also increases hardness, and impairs the corrosion resistance. Mo is also an expensive element, and increases the manufacturing cost. For this reason, the Mo content is limited to 1.0 to 2.7%. Preferably, the Mo content is 1.5 to 2.5%. Al : 0.1% or Less
    [0025] Al acts as a deoxidizing agent, and an Al content of 0.01% or more is effective for obtaining this effect. However, Al has an adverse effect on toughness when contained in an amount of more than 0.1%. For this reason, the Al content is limited to 0.1% or less in the present invention. Preferably, the Al content is 0.01 to 0.03%. V: 0.2% or Less
    [0026] V is contained in an amount of desirably 0.005% or more to improve steel strength through precipitation hardening, and to improve sulfide stress corrosion cracking resistance. Because a V content of more than 0.2% impairs toughness, the V content is limited to 0.2% or less in the present invention. The V content is preferably 0.01 to 0.08%. N: 0.1% or Less
    [0027] N is an element that greatly improves pitting corrosion resistance. However, N forms various nitrides, and impairs toughness when contained in an amount of more than 0.1%. For this reason, the N content is limited to 0.1% or less in the present invention. Preferably, the N content is 0.004 to 0.08%, more preferably 0.005 to 0.05%. Ti: 0.01 to 0.50%
    [0028] Ti forms titanium carbides by binding to C, and makes the C content considerably small. A Ti content of 0.01% or more is needed to obtain this effect. When contained in an amount of more than 0.50%, Ti generates coarse carbides, which impair toughness and sulfide stress corrosion cracking resistance. For this reason, the Ti content is limited to 0.01 to 0.50%. The Ti content is preferably 0.05 to 0.15%. Cu: 0.01 to 1.0%
    [0029] When contained in an amount of 0.01% or more, Cu adds strength to the protective coating, reduces active dissolution, and improves sulfide stress corrosion cracking resistance. When contained in an amount of more than 1.0%, Cu precipitates into CuS, and impairs hot workability. For this reason, the Cu content is limited to 0.01 to 1.0%. Co: 0.01 to 1.0%
    [0030] Co is an element that reduces hardness, and improves pitting corrosion resistance by raising the Ms point, and promoting α transformation. Co needs to be contained in an amount of 0.01% or more to obtain these effects . When contained in excessively large amounts, Co may impair toughness, and increases the material cost. For this reason, the Co content is limited to 0.01 to 1.0% in the present invention.
    [0031] In the present invention, C, Mn, Cr, Cu, Ni, Mo, W, Nb, N, and Ti are contained so that the values of the following formulae (1) and (2) satisfy the formulae (3) below. Formula (1) correlates these elements with an amount of retained γ. By making the value of formula (1) smaller, the retained austenite occurs in smaller amounts, the hardness decreases, and the sulfide stress corrosion cracking resistance improves. Formula (2) correlates the elements with pitting corrosion potential. When C, Mn, Cr, Cu, Ni, Mo, W, N, and Ti are contained so that the value of formula (2) satisfies the range of formula (3), generation of pitting corrosion, which becomes an initiation point of sulfide stress corrosion cracking, can be reduced, and the sulfide stress corrosion cracking resistance greatly improves. The hardness increases when the value of formula (1) is 10 or more. However, it is still possible to effectively reduce generation of pitting corrosion and improve sulfide stress corrosion cracking resistance when the value of formula (2) satisfies the range of formula (3). − 109.37 C + 7.307 Mn + 6.399 Cr + 6.329 Cu + 11.343 Ni − 13.259 Mo + 1.276 W + 2.925 Nb + 196.775 N − 2.621 Ti − 120.307
    [0032] In the formulae, C, Mn, Cr, Cu, Ni, Mo, W, Nb, N, and Ti represent the content of each element in mass%, and the content is 0 (zero) for elements that are not contained. − 35.0 ≤ value of formula 1 ≤ 45 ,and − 0.40 ≤ value of formula 2 ≤ 0.070
    [0033] At least one selected from Nb: 0.25% or less, and W: 1.1% or less may be contained as optional elements, as needed.
    [0034] Nb forms carbides, and can reduce hardness by reducing solid-solution carbon. However, Nb may impair toughness when contained in an excessively large amount. W is an element that improves pitting corrosion resistance. However, W may impair toughness, and increases the material cost when contained in an excessively large amount. For this reason, Nb and W, when contained, are contained in limited amounts of Nb: 0.25% or less, and W: 1.1% or less.
    [0035] One or more selected from Ca: 0.010% or less, REM: 0.010% or less, Mg: 0.010% or less, and B: 0.010% or less may be contained as optional elements, as needed.
    [0036] Ca, REM, Mg, and B are elements that improve corrosion resistance by controlling the form of inclusions. The desired contents for providing this effect are Ca: 0.0005% or more, REM: 0.0005% or more, Mg: 0.0005% or more, and B: 0.0005% or more. Ca, REM, Mg, and B impair toughness and carbon dioxide corrosion resistance when contained in amounts of more than Ca: 0.010%, REM: 0.010%, Mg: 0.010%, and B: 0.010%. For this reason, the contents of Ca, REM, Mg, and B, when contained, are limited to Ca: 0.010% or less, REM: 0.010% or less, Mg: 0.010% or less, and B: 0.010% or less.
    [0037] The balance is Fe and incidental impurities in the composition.
    [0038] The following describes a preferred method for manufacturing a stainless steel seamless pipe for oil country tubular goods of the present invention.
    [0039] In the present invention, a steel pipe material of the foregoing composition is used. However, the method of production of a stainless steel seamless pipe used as a steel pipe material is not particularly limited, and any known seamless pipe producing method may be used.
    [0040] Preferably, a molten steel of the foregoing composition is made into steel using an ordinary steel making process such as by using a converter, and formed into a steel pipe material, for example, a billet, using a method such as continuous casting, or ingot casting-blooming. The steel pipe material is then heated, and hot worked into a pipe using a known pipe manufacturing process, for example, the Mannesmann-plug mill process, or the Mannesmann-mandrel mill process to produce a seamless steel pipe of the foregoing composition.
    [0041] The process after the production of the steel pipe from the steel pipe material is not particularly limited. Preferably, the steel pipe is subjected to quenching in which the steel pipe is heated to a temperature equal to or greater than an AC3 transformation point, and cooled to a cooling stop temperature of 100°C or less, followed by tempering at a temperature equal to or less than an AC1 transformation point. Quenching
    [0042] In the present invention, the steel pipe is reheated to a temperature equal to or greater than an AC3 transformation point, held for preferably at least 5 min, and cooled to a cooling stop temperature of 100°C or less. This makes it possible to produce a refined, tough martensite phase. When the quenching heating temperature is less than an AC3 transformation point, the microstructure does not occur in the austenite single-phase region, and a sufficient martensite microstructure does not occur in the subsequent cooling, with the result that the desired high strength cannot be obtained. For this reason, the quenching heating temperature is limited to a temperature equal to or greater than an AC3 transformation point. The cooling method is not limited. Typically, the steel pipe is air cooled (at a cooling rate of 0.05°C/s or more and 20°C/s or less) or water cooled (at a cooling rate of 5°C/s or more and 100°C/s or less), and the cooling rate conditions are not limited either. Tempering
    [0043] The quenched steel pipe is tempered. The tempering is a process in which the steel pipe is heated to a temperature equal to or less than an AC1 transformation point, held for preferably at least 10 min, and cooled. When the tempering temperature is higher than an AC1 transformation point, the martensite phase precipitates after the tempering, and the desired high toughness and excellent corrosion resistance cannot be provided. For this reason, the tempering temperature is limited to a temperature equal to or less than an AC1 transformation point. The AC3 transformation point (°C) and the AC1 transformation point (°C) can be determined by giving a heating and cooling temperature history to a test piece, and finding a transformation point from a microdisplacement due to expansion and contraction in a Formaster test. Examples
    [0044] The present invention is further described below through Examples.
    [0045] 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.
    [0046] 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.
    [0047] 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 converted using the following equation. γvolume fraction = 100 / 1 + I α R γ / I γ R α
    [0048] In the equation, Iα represents the integral intensity of α, Rα represents a crystallographic theoretical calculation value for α, Iγ represents the integral intensity of γ, and Rγ represents a crystallographic theoretical calculation value for γ.
    [0049] An arc-shaped tensile test specimen specified by API standard was taken from the quenched and tempered test material, and the tensile properties (yield stress, YS; tensile stress, TS) were determined in a tensile test conducted according to the API specification. The AC3 point (°C) and AC1 point (°C) in Table 2 were measured in a Formaster test using a test piece (4mmφ × 10 mm) taken from the quenched test material. Specifically, the test piece was heated to 500°C at 5°C/s, and to 920°C at 0.25°C/s. After being held for 10 minutes, and test piece was cooled to room temperature at a rate of 2°C/s. The expansion and contraction of the test piece with this temperature history were then detected to obtain the AC3 point (°C) and AC1 point (°C) .
    [0050] The SSC test was conducted according to NACE TM0177, Method A. A test environment was created by adjusting the pH of a test solution (a 0. 165 mass% NaCl aqueous solution; liquid temperature: 25°C; H2S: 1 bar; CO2 bal.) to 3.5 with addition of 0.41 g/L of CH3COONa and HCl, and a stress 90% of the yield stress was applied under a hydrogen sulfide partial pressure of 0.1 MPa for 720 hours in the solution. Samples were determined as being acceptable when there was no crack in the test piece after the test, and unacceptable when the test piece had a crack after the test.
    [0051] The results are presented in Table 2.
    [0052] Table 2Steel pipe No.Steel No.QuenchingTemperingMicrostructureTensile propertiesSSC resistance testRemarksAc3 point (°C)Heating temp. (°C)Holding time (min)CoolingCooling stop temp. (°C)Ac1 point (°C)Heating temp. (°C)Holding time (min)Retained γ (*1) (volume%)Yield stress YS (MPa)Tensile stress TS (MPa)Presence or absence of cracki ng1A74592020Air cooling25655585600.17839871AbsentPresent Example2B74592020Air cooling25640605601.27792834AbsentPresent Example3C73592020Air cooling25660595600.51841878AbsentPresent Example4D71592020Water cooling25635590600.49796829AbsentPresent Example5E75592020Water cooling25650585600.21822856AbsentPresent Example6F71592020Air cooling25660610600.79817843AbsentPresent Example7G73592020Air cooling25660605600.56824864AbsentPresent Example8H72092020Air cooling25655595600.73836875AbsentPresent Example9I75092020Air cooling25660605600.42827869AbsentPresent Example10J67092020Air cooling25625575600.83787819AbsentPresent Example 11A74573020Air cooling25655585604.32761813PresentComparative Example12B74592020Air cooling25640645605.68764826PresentComparative Example13K69092020Air cooling25665615600.62826874PresentComparative Example14L68592020Air cooling25660610600.94794835PresentComparative Example15M73092020Air cooling25665600600.78822876PresentComparative Example16N74592020Water cooling25645605600.37840884PresentComparative Example17O80092020Water cooling25665610600.43836879PresentComparative Example18P79592020Air cooling25675615602.79840891PresentComparative Example19Q68092020Air cooling25650600600.44816868PresentComparative Example20R77092020Air cooling25640605600.30802843PresentComparative Example21S75592020Air cooling25635595603.96792834PresentComparative Example (*1) Retained γ: Retained austenite* Underline means outside the range of the invention
    [0053] The steel pipes of the present examples all had high strength with a yield stress of 758 MPa or more, demonstrating that the steel pipes were martensitic stainless steel seamless pipes having excellent SSC resistance that do not crack even when placed under a stress in a H2S-containing environment. On the other hand, in Comparative Examples outside the range of the present invention, the steel pipes did not have excellent SSC resistance, even though the desired high strength was obtained.
    权利要求:
    Claims (4)
    [0001] A martensitic stainless steel seamless pipe for oil country tubular goods having a yield stress of 758 MPa or more,the martensitic stainless steel seamless pipe having a composition that comprises, in mass%, C: 0.0010 to 0.0094%, Si: 0. 5 % or less, Mn: 0.05 to 0. 5%, P: 0. 030 % or less, S: 0. 005% or less, Ni: 4.6 to 7.3%, Cr: 10.0 to 14.5%, Mo: 1.0 to 2.7%, Al : 0.1% or less, V: 0.2% or less, N: 0.1% or less, Ti: 0.01 to 0.50%, Cu: 0.01 to 1.0%, and Co: 0.01 to 1.0%, in which the values of the following formulae (1) and (2) satisfy the formulae (3) below, and the balance is Fe and incidental impurities: − 109.37 C + 7.307 Mn + 6.399 Cr + 6.329 Cu + 11.343 Ni − 13.529 Mo + 1.276 W + 2.925 Nb + 196.775 N − 2.621 Ti − 120.307 ,
    [0002] The martensitic stainless steel seamless pipe for oil country tubular goods according to claim 1, wherein the composition further comprises, in mass%, one or two selected from Nb: 0.25% or less, and W: 1.1% or less.
    [0003] The martensitic stainless steel seamless pipe for oil country tubular goods according to claim 1 or 2, wherein the composition further comprises, in mass%, one, two or more selected from Ca: 0.010% or less, REM: 0.010% or less, Mg: 0.010% or less, and B: 0.010% or less.
    [0004] A method for manufacturing a martensitic stainless steel seamless pipe for oil country tubular goods,the method comprising:
    forming a steel pipe from a steel pipe material of the composition of any one of claims 1 to 3;
    quenching the steel pipe by heating the steel pipe to a temperature equal to or greater than an AC3 transformation point, and cooling the steel pipe to a cooling stop temperature of 100°C or less; and
    tempering the steel pipe at a temperature equal to or less than an AC1 transformation point.
    类似技术:
    公开号 | 公开日 | 专利标题
    EP3192890B1|2019-10-09|High strength seamless steel pipe for use in oil wells and manufacturing method thereof
    RU2584100C1|2016-05-20|High-strength seamless pipe of stainless steel of oilfield range and method for manufacture thereof
    CA2849287C|2016-11-29|Method for producing high-strength steel material excellent in sulfide stress cracking resistance
    JP2015038247A|2015-02-26|High-strength seamless steel pipe with excellent resistance to sulfide stress cracking for oil well and method for producing the same
    US9708681B2|2017-07-18|High-strength seamless steel pipe for oil well use having excellent resistance to sulfide stress cracking
    JP5967066B2|2016-08-10|High strength stainless steel seamless steel pipe for oil well with excellent corrosion resistance and method for producing the same
    JP5109222B2|2012-12-26|High strength stainless steel seamless steel pipe for oil well with excellent corrosion resistance and method for producing the same
    JP4140556B2|2008-08-27|Low alloy steel for oil well pipes with excellent resistance to sulfide stress cracking
    RU2588755C2|2016-07-10|Steel strip with low ratio of yield strength to ultimate strength and high impact strength and method for production thereof
    JP4632000B2|2011-02-23|Seamless steel pipe manufacturing method
    JP4609138B2|2011-01-12|Manufacturing method of oil well pipe steel excellent in sulfide stress cracking resistance and oil well seamless steel pipe
    AU2008221597B2|2010-04-01|Low alloy steel, seamless steel oil country tubular goods, and method for producing seamless steel pipe
    ES2703049T3|2019-03-06|Stainless steel for oil wells and stainless steel pipe for oil wells
    JP4363327B2|2009-11-11|Stainless steel pipe for oil well and manufacturing method thereof
    JP6107437B2|2017-04-05|Manufacturing method of low-alloy high-strength seamless steel pipe for oil wells with excellent resistance to sulfide stress corrosion cracking
    JP5092204B2|2012-12-05|Stainless steel pipe for oil wells with excellent pipe expandability
    EP1546417B1|2012-04-25|High strength seamless steel pipe excellent in hydrogen-induced cracking resistance and its production method
    RU2696513C2|2019-08-02|Martensitic-ferritic stainless steel, manufactured product and methods of their application
    EP2865775B1|2018-08-08|Steel for oil well pipe, oil well pipe, and method for producing same
    US9303296B2|2016-04-05|High-strength stainless steel for oil well and high-strength stainless steel pipe for oil well
    EP2728030B1|2017-12-27|Thick-walled high-strength seamless steel pipe with excellent sour resistance for pipe for pipeline, and process for producing same
    JPWO2015178022A1|2017-04-20|High strength stainless steel seamless steel pipe for oil well and method for producing the same
    JP4893196B2|2012-03-07|High strength stainless steel pipe for oil well with high toughness and excellent corrosion resistance
    JP4761008B2|2011-08-31|High-strength stainless steel pipe with excellent resistance to sulfide stress cracking and high temperature carbon dioxide corrosion
    EP2177634B1|2018-01-17|Process for production of duplex stainless steel tubes
    同族专利:
    公开号 | 公开日
    BR112020004809A2|2020-09-24|
    US20200270715A1|2020-08-27|
    JPWO2019065116A1|2019-11-14|
    WO2019065116A1|2019-04-04|
    JP6540922B1|2019-07-10|
    EP3690072A4|2020-08-05|
    AR113184A1|2020-02-05|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2019-04-06| STAA| Information on the status of an ep patent application or granted ep patent|Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE |
    2020-07-03| PUAI| Public reference made under article 153(3) epc to a published international application that has entered the european phase|Free format text: ORIGINAL CODE: 0009012 |
    2020-07-03| STAA| Information on the status of an ep patent application or granted ep patent|Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
    2020-08-05| A4| Supplementary search report drawn up and despatched|Effective date: 20200605 |
    2020-08-05| AK| Designated contracting states|Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
    2020-08-05| AX| Request for extension of the european patent|Extension state: BA ME |
    2020-08-05| 17P| Request for examination filed|Effective date: 20200311 |
    2021-01-06| DAV| Request for validation of the european patent (deleted)|
    2021-01-06| DAX| Request for extension of the european patent (deleted)|
    优先权:
    申请号 | 申请日 | 专利标题
    [返回顶部]