Jfe Steel Corporation

Nec Corporation

Yuichi Kamo

Masao Yuga

Mami Endo

Kenichiro Eguchi

Nobuo Mikami

Yasuhide Ishiguro

Yusuke Yoshimura

Hiroki Ota

Shunsuke Sasaki

Kazutoshi Wakamatsu

Katsuto Kojima

Kunio Naito

A stainless steel seamless pipe having high strength and excellent corrosion resistance. The stainless steel seamless pipe has a specified composition in which C, Si, Mn, Cr, Ni, Mo, Cu, and N satisfy a predetermined formula, a microstructure containing at least 25% martensitic phase, at most 65% ferrite phase, and at most 40% retained austenite phase by volume, and a yield strength of 758 MPa or more.

Stainless steel seamless pipe and method for manufacturing same

Provided herein is a stainless steel seamless pipe having a composition that contains, in mass %, C: 0.06% or less, Si: 1.0% or less, Mn: 0.01% or more and 1.0% or less, P: 0.05% or less, S: 0.005% or less, Cr: 15.2% or more and 18.5% or less, Mo: 1.5% or more and 4.3% or less, Cu: 1.1% or more and 3.5% or less, Ni: 3.0% or more and 6.5% or less, Al: 0.10% or less, N: 0.10% or less, O: 0.010% or less, and Sb: 0.001% or more and 1.000% or less, and in which C, Si, Mn, Cr, Ni, Mo, Cu, and N satisfy the predetermined formula, and the balance is Fe and incidental impurities, the stainless steel seamless pipe having a microstructure containing 30% or more martensitic phase, 65% or less ferrite phase, and 40% or less retained austenite phase by volume.

Stainless steel seamless pipe and method for manufacturing stainless steel seamless pipe

Provided is duplex stainless steel which has high strength and high toughness and can be subjected to hot working during manufacturing processes, the duplex stainless steel having a predetermined chemical composition and a microstructure containing an austenite phase in a volume fraction of 20% to 70% and a ferrite phase in a volume fraction of 30% to 80%, and mechanical properties such that a yield strength is 862 MPa or more and an absorption energy in a Charpy impact test at −10° C., vE, is 40 J or more.

Duplex stainless steel, seamless steel pipe or tube, and a method of manufacturing the duplex stainless steel

A stainless steel seamless pipe having high strength and excellent corrosion resistance, and a method for producing the same. The stainless steel seamless pipe has a specified composition and satisfies a predetermined formula. The stainless steel seamless pipe has a microstructure containing at least 30% martensitic phase, at most 60% ferrite phase, and at most 40% retained austenite phase by volume, the stainless steel seamless pipe having a yield strength of 758 MPa or more.

The disclosure 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 and a method for manufacturing thereof. The martensitic stainless steel seamless pipe for oil country tubular goods has a composition that contains, in mass %, C: 0.0100% or more, Si: 0.5% or less, Mn: 0.25 to 0.50%, 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 predetermined relations, and the balance is Fe and incidental impurities. The martensitic stainless steel seamless pipe has a yield stress of 758 MPa or more.

Martensitic stainless steel seamless pipe for oil country tubular goods, and method for manufacturing same

The invention is intended to provide a martensitic stainless steel seamless pipe for oil country tubular goods having a yield stress of 758 MPa or more, 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 composition that contains, in mass %, C: 0.010% or more, Si: 0.5% or less, Mn: 0.05 to 0.50%, 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: 0.010 to 0.054%, Cu: 0.01 to 1.0%, and Co: 0.01 to 1.0%. C, Mn, Cr, Cu, Ni, Mo, W, N, and Ti satisfy the predetermined relations, and the balance is Fe and incidental impurities. The martensitic stainless steel seamless pipe has a yield stress of 758 MPa or more.

A stainless steel seamless pipe having high strength, excellent low-temperature toughness and corrosion resistance, and a composition including, in mass %, C: 0.06% or less, Si: 1.0% or less, Mn: 0.01% or more and 1.0% or less, P: 0.05% or less, S: 0.005% or less, Cr: 14.0% or more and 17.0% or less, Mo: more than 3.80% and 6.0% or less, Cu: more than 1.03% and 3.5% or less, Ni: 3.5% or more and 6.0% or less, Al: 0.10% or less, N: 0.10% or less, O: 0.010% or less, and the balance is Fe and incidental impurities. Elements C, Si, Mn, Cr, Ni, Mo, Cu, and N satisfy a predetermined relationship. The stainless steel seamless pipe has a yield strength of 862 MPa or more and has a microstructure that contains at least 40% martensitic phase, at most 60% ferrite phase, and at most 30% retained austenite phase by volume.

Stainless steel seamless pipe

The invention provides a martensitic stainless steel seamless pipe for oil country tubular goods having high strength, 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 has a yield stress of 655 to 758 MPa, and has a composition containing, in mass %, C: 0.10% or less, Si: 0.5% or less, Mn: 0.05 to 2.0%, P: 0.030% or less, S: 0.005% or less, Ni: 4.0 to 8.0%, Cu: 0.02% or more and less than 1.0%, Cr: 10.0 to 14.0%, Mo: 1.0 to 3.5%, V: 0.003 to 0.2%, Co: 0.02% or more and less than 1.0%, Al: 0.1% or less, N: 0.1% or less, Ti: 0.50% or less, and the balance Fe and incidental impurities, wherein C, Mn, Cr, Cu, Co, Ni, Mo, W, Nb, N, and Ti satisfy the predetermined relations.

A martensitic stainless steel seamless pipe for oil country tubular goods having a yield stress of 758 MPa or more, and excellent sulfide stress corrosion cracking resistance, and a method for manufacturing the same. The martensitic stainless steel seamless pipe has a composition that contains, by mass %, C: 0.010% or more, Si: 0.5% or less, Mn: 0.05 to 0.50%, 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: 0.255 to 0.500%, Cu: 0.01 to 1.0%, Co: 0.01 to 1.0%, and the balance being Fe and incidental impurities. C, Mn, Cr, Cu, Ni, Mo, W, Nb, N, and Ti satisfy a predetermined relationship.

Provided herein is a dual-phase stainless steel having excellent carbon dioxide corrosion resistance, excellent sulfide stress corrosion cracking resistance, and excellent sulfide stress cracking resistance. The dual-phase stainless steel contains, in mass %, C: 0.03% or less, Si: 1.0% or less, Mn: 0.10 to 1.5%, P: 0.030% or less, S: 0.005% or less, Cr: 20.0 to 30.0%, Ni: 5.0 to 10.0%, Mo: 2.0 to 5.0%, Cu: 2.0 to 6.0%, N: less than 0.07%, and the balance Fe and unavoidable impurities, and has a structure that is 20 to 70% austenite phase, and 30 to 80% ferrite phase in terms of a volume fraction.

Dual-phase stainless steel, and method of production thereof

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.

Provided herein is a high-strength stainless steel seamless pipe for oil country tubular goods. The high-strength stainless steel seamless pipe having a yield strength of 862 MPa or more contains, in mass %, C:0.05% or less, Si: 0.5% or less, Mn: 0.15 to 1.0%, P: 0.030% or less, S: 0.005% or less, Cr: 14.5 to 17.5%, Ni: 3.0 to 6.0%, Mo: 2.7 to 5.0%, Cu: 0.3 to 4.0%, W: 0.1 to 2.5%, V: 0.02 to 0.20%, Al: 0.10% or less, N: 0.15% or less, B: 0.0005 to 0.0100%, and the balance Fe and unavoidable impurities, and in which the composition satisfies specific formulas. The stainless steel pipe has more than 45% martensite phase, 10 to 45% ferrite phase, and 30% or less retained austenite phase. The ferrite grains have a maximum crystal grain size of 500 &#x3bc;m or less.

High-strength stainless steel seamless pipe for oil country tubular goods, and method for producing same

The invention is intended to provide a high-strength stainless steel seamless pipe for oil country tubular goods having high strength with a yield strength of 862 MPa (125 ksi) or more, excellent low-temperature toughness, and excellent corrosion resistance. The invention is also intended to provide a method for manufacturing such a high-strength stainless steel seamless pipe. The high-strength stainless steel seamless pipe has a microstructure that is at least 45% tempered martensite phase, 20 to 40% ferrite phase, and more than 10% and 25% or less retained austenite phase by volume. The high-strength stainless steel seamless pipe has a yield strength of 862 MPa or more, and a maximum crystal grain diameter of 500 &#x3bc;m or less for ferrite crystal grains when crystal grains with a crystal orientation difference of within 15&#xb0; are defined as the same crystal grains.

High-strength stainless steel seamless pipe for oil country tubular goods, and method for manufacturing same

Provided herein is a high strength seamless stainless steel pipe. A method for producing such a high strength seamless stainless steel pipe is also provided. The high strength seamless stainless steel pipe has a certain composition. The high strength seamless stainless steel pipe has a structure that includes a tempered martensite phase as a primary phase, and 20 to 40% ferrite phase, and at most 25% residual austenite phase in terms of a volume fraction, and in which C, Cr, Ni, Mo, Nb, N, W, and Cu in the residual austenite phase satisfy a predetermined formula.

High strength seamless stainless steel pipe and method for producing same

A bistable type of electromagnetic relay has a movable block including a pair of permanent magnet units. Each of the magnet units has a permanent magnet and a pair of generally U-shaped magnetic plates attached to its opposite poles. A rotation of the movable body actuates relay contact members. A yoke has opposite ends, each formed by a pair of opposing end pieces, the end of the magnetic plates being arranged in spaces defined by the opposing end pieces. A coil supporting a spool has a through-hole for receiving a core which is inserted therein. Flanges are formed at opposite ends and at a center portion of the spool, with a plurality of protrusions protruding outwardly on both sides of each flange. A pair of base members have grooves and recesses for receiving the protrusions on the flanges of the spool, for rotatably supporting the movable block.

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Tokyo, Japan

Yuichi Kamo