Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Mitsuru Sawamura

Tatsuo Fujimoto

Noboru Ohtani

Masashi Nakabayashi

Hitoshi Asahi

Yasunori Takahashi

Eiji Tsuru

Mitsuru Morita

Naoki Saitoh

Katsumi Kurebayashi

Takumi Miyake

Jun Agata

In a steel plate according to the present invention, a chemical composition is within a predetermined range, an &#x3b1; value is 0.13 to 1.0 mass %, a &#x3b2; value is 8.45 to 15.2, an yield strength is 670 to 870 N/mm, a tensile strength is 780 to 940 N/mm, an average grain size at &#xbd;t of the steel plate is 35 &#x3bc;m or less, and a plate thickness is 25 to 200 mm. In the steel plate according to the present invention, in a case where SR is performed on the steel, a charpy absorbed energy at &#x2212;40&#xb0; C. in an area in which SR is performed may be 100 J or more.

[object Object]

A steel pipe with dual phase structure includes, as chemical composition, by mass %, C: 0.07% to 0.15%, Si: 0.1% to 0.5%, Mn: 0.8% to 1.9%, Nb: 0.020% to 0.10%, P: limited to 0.05% or less, S: limited to 0.01% or less, Al: limited to 0.1% or less, and a balance consisting of iron and unavoidable impurities, wherein, when [X] is amount of element X in mass %, carbon equivalent Ceq defined by Equation of Ceq=[C]+[Mn]/6 is 0.25 to 0.40 and [Nb]&#xd7;[C]&#x2267;0.002 is satisfied, and includes, as metallographic structure, by area %, ferrite of 80% to 98% and martensite, residual austenite, or mixture thereof of 2% to 20% in total, wherein average grain size of ferrite is 1 &#x3bc;m to less than 8 &#x3bc;m and average grain size of martensite, residual austenite, or mixture thereof is 0.1 &#x3bc;m to 2 &#x3bc;m.

Oil country tubular goods with dual phase structure and producing method thereof

[Summary] [Object] There are provided electric resistance welded oil country tubular goods having strength corresponding to API specification 5CT P110 without a heat treatment being performed on the whole steel pipe and further having excellent toughness, and a manufacturing method of an electric resistance welded oil country tubular goods. [Solution] Electric resistance welded oil country tubular goods according to the present invention have a chemical composition that contains, in mass %, C: 0.05 to 0.12%, Si: 0.03 to 0.5%, Mn: 0.80 to 2.2%, P: 0.03% or less, S: 0.003% or less, Al: 0.08% or less, Nb: 0.01% to 0.10%, Ti: 0.005 to 0.03%, B: 0.0005 to 0.0030%, and N: 0.008% or less, and in which Ti&#x3e;3.4 N is satisfied, its balance is composed of Fe and inevitable impurities, and, Vis 15 to 40.

Electric resistance welded oil country tubular goods and manufacturing method of electric resistance welded oil country tubular goods

Provided is a monocrystalline silicon carbide ingot containing a dopant element, wherein a maximum concentration of the dopant element is less than 5&#xd7;10atoms/cmand the maximum concentration is 50 times or less than that of a minimum concentration of the dopant element. Also provided is a monocrystalline silicon carbide wafer made by cutting and polishing the monocrystalline silicon carbide ingot, wherein a electric resistivity at room temperature of the wafer is 5&#xd7;10&#x3a9;cm or more. Further provided is a method for manufacturing the monocrystalline silicon carbide including growing the monocrystalline silicon carbide on a seed crystal from a sublimation material by a sublimation method. The sublimation material includes a solid material containing a dopant element, and the specific surface of the solid material containing the dopant element is 0.5 m/g or less.

Monocrystalline silicon carbide ingot, monocrystalline silicon carbide wafer and method of manufacturing the same

The present invention provides a high resistivity, high quality, large size SiC single crystal, SiC single crystal wafer, and method of production of the same, that is, a silicon carbide single crystal containing uncompensated impurities in an atomic number density of 1&#xd7;10/cmor more and containing vanadium in an amount less than said uncompensated impurity concentration, silicon carbide single crystal wafer obtained by processing and polishing the silicon carbide single crystal and having an electrical resistivity at room temperature of 5&#xd7;10&#x3a9;cm or more, and a method of production of a silicon carbide single crystal.

Silicon carbide single crystal, silicon carbide single crystal wafer, and method of production of same

The present invention provides a semi-insulating silicon carbide single crystal characterized by having an electrical resistivity at room temperature of 1&#xd7;10&#x3a9;cm or more, and a semi-insulating silicon carbide single crystal characterized by having an electrical resistivity at room temperature of 1&#xd7;10&#x3a9;cm or more and vacancy pairs (bivacancies), and an semi-insulating silicon carbide single crystal characterized by having an electrical resistivity at room temperature of 1&#xd7;10&#x3a9;cm or more and containing a crystal region where a position average lifetime becomes a lifetime longer than 155 ps in measurement of position lifetime at a liquid nitrogen boiling point temperature (77K) or less, and wafer obtained therefrom. According to the present invention, by having vacancy clusters including vacancy pairs, the electrical conductivity can be reduced even when the nitrogen concentration is higher than the boron concentration and, in addition, a semi-insulating SiC single crystal resistant to change of the electrical conductivity even with heat treatment can be obtained.

Silicon carbide single crystal and single crystal wafer

The present invention provides a high resistivity, high quality, large size SiC single crystal, SiC single crystal wafer, and method of production of the same, that is, a silicon carbide single crystal containing uncompensated impurities in an atomic number density of 1 &#xd7;10/cmor more and containing vanadium in an amount less than said uncompensated impurity concentration, silicon carbide single crystal wafer obtained by processing and polishing the silicon carbide single crystal and having an electrical resistivity at room temperature of 5&#xd7;10&#x3a9;cm or more, and a method of production of a silicon carbide single crystal.

A large superconductor intermediate of REBa Cu O system (where RE is one kind or a combination of rare earth elements including Y), characterized by a structure that oxide superconductors having non-superconductive phases finely dispersed in REBa Cu O phases (123 phases) of different peritectic temperatures (Tp) are laminated three-dimensionally in the order of Tp's, seed crystals mounted on the oxide superconductor layer having a highest Tp, and excluded phases included in at least the oxide superconductor having the high Tp.

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Futtsu, Japan

Mitsuru Sawamura