Nippon Steel Corporation

Nippon Steel & Sumitomo Metal Corporation

Fukujukogyo Co., Ltd.

Ryuji Uemori

Yoshiyuki Watanabe

Akihiko Kojima

Rikio Chijiiwa

Kazuhiro Fukunaga

Hiroyuki Kondo

Koichi Chiba

Eiichi Takeuchi

Takehiko Toh

Ryuichi Honma

Akihiro Ono

Kazushige Umezawa

Masamitsu Wakoh

Katsuhiro Fuchigami

Tokio Suzuki

Tadashi Ishikawa

Manabu Hoshino

Toshihiro Hanamura

Jin-ichi Takamura

Mitsuru Tanino

Yoshihide Nagai

Yasushi Hasegawa

Takuya Hara

Hitoshi Asahi

Yasunori Takahashi

Hiroshi Tamehiro

Hajime Ishikawa

Naoki Saitoh

Yutaka Takagi

Motohiro Okushima

Hitoshi Furuya

Naoki Saito

Nobuhiko Mamada

Takehiro Inoue

A steel for electron-beam welding according to the present invention includes at least C: 0.02% to 0.10%, Si: 0.03% to 0.30%, Mn: 1.5% to 2.5%, Ti: 0.005% to 0.015%, N: 0.0020% to 0.0060%, and O: 0.0010% to 0.0035%, further includes S: limited to 0.010% or less, P: limited to 0.015% or less, and Al: limited to 0.004% or less, with a balance including iron and inevitable impurities. An index value CeEBB obtained by substituting composition of the steel into following Formula 1 falls in the range of 0.42 to 0.65%, the number of oxide having an equivalent circle diameter of 1.0 &#x3bc;m or more is 20 pieces/mmor less at a thickness center portion in cross section along the thickness direction of the steel, and the number of oxide containing Ti of 10% or more and having an equivalent circle diameter of not less than 0.05 &#x3bc;m or more and less than 0.5 &#x3bc;m falls in the range of 1&#xd7;10to 1&#xd7;10pieces/mmat the thickness center portion.CeEBB=C+&#xbc;Mn+ 1/15Cu+ 1/15Ni+&#x2155;Cr+&#x2155;Mo+&#x2155;V&#x2003;&#x2003;(Formula 1)

Electron-beam welded joint, steel for electron-beam welding, and method of manufacturing the same

A steel for a welded structure includes the following composition: by mass %, C at a C content [C] of 0.010 to 0.065%; Si at a Si content [Si] of 0.05 to 0.20%; Mn at a Mn content [Mn] of 1.52 to 2.70%; Ni at a Ni content [Ni] of 0.10% to 1.50%; Ti at a Ti content [Ti] of 0.005 to 0.015%; O at an O content [O] of 0.0010 to 0.0045%; N at a N content [N] of 0.002 to 0.006%; Mg at a Mg content [Mg] of 0.0003 to 0.003%; Ca at a Ca content [Ca] of 0.0003 to 0.003%; and the balance composed of Fe and unavoidable impurities. A steel component parameter Pis 0.065% or less, and a steel component hardness parameter CeqH is 0.235% or less.

Steel for welded structure and producing method thereof

A Ni-added steel plate contains, by mass %, C: 0.03% to 0.10%, Si: 0.02% to 0.40%, Mn: 0.3% to 1.2%, Ni: 5.0% to 7.5%, Cr: 0.4% to 1.5%, Mo: 0.02% to 0.4%, Al: 0.01% to 0.08%, T.O: 0.0001% to 0.0050%, P: limited to 0.0100% or less, S: limited to 0.0035% or less, and N: limited to 0.0070% or less with a remainder composed of Fe and inevitable impurities, in which a Ni segregation ratio at a position of &#xbc; of a plate thickness away from a plate surface in a thickness direction is 1.3 or less, a fraction of austenite after deep cooling is 2% or more, an austenite unevenness index after deep cooling is 5.0 or less, and an average equivalent circle diameter of austenite after deep cooling is 1 &#x3bc;m or less.

Ni-added steel plate and method of manufacturing the same

A steel for a welded structure includes the following composition: by mass %, C at a C content [C] of 0.015 to 0.045%; Si at a Si content [Si] of 0.05 to 0.20%; Mn at a Mn content [Mn] of 1.5 to 2.0%; Ni at a Ni content [Ni] of 0.10 to 1.50%; Ti at a Ti content [Ti] of 0.005 to 0.015%; O at an O content [O] of 0.0015 to 0.0035%; and N at a N content [N] of 0.002 to 0.006%, and a balance composed of Fe and unavoidable impurities. In the steel for a welded structure, the P content [P] is limited to 0.008% or less, the S content [S] is limited to 0.005% or less, the Al content [Al] is limited to 0.004% or less, the Nb content [Nb] is limited to 0.005% or less, the Cu content [Cu] is limited to 0.24% or less, the V content [V] is limited to 0.020% or less, and a steel composition parameter Pis 0.065% or less, and a steel composition hardness parameter CeqH is 0.235% or less.

The present invention provides steel plate for line pipe excellent in strength and ductility and a method of production of the same. The steel plate has a steel composition containing, by mass %, C: 0.04 to 0.15%, Si: 0.05 to 0.60%, Mn: 0.80 to 1.80%, P: 0.020% or less, S: 0.010% or less, Nb: 0.01 to 0.08%, and Al: 0.003 to 0.08%, having a balance of iron and unavoidable impurities, and having a value of Ceq shown by the following formula &#x3c;1&#x3e; of 0.48 or less, comprised of a mixed structure of ferrite and pearlite or ferrite and pearlite partially containing bainite in which a ferrite percentage is 60 to 95%, having a yield strength of 450 MPa or more, and having an amount of hydrogen contained in the steel of 0.1 ppm or less:Ceq=C+Mn/6+(Cu+Ni)/15+(Cr+Mo+Nb+V+Ti)/5+5B&#x2003;&#x2003;&#x3c;1&#x3e;.

Steel plate for line pipe excellent in strength and ductility and method of production of same

An electron-beam welded joint including, by mass %, C: 0.02% to 0.1%, Si: 0.03% to 0.30%, Mn: 1.5% to 2.5%, Ti: 0.005 to 0.015%, N: 0.0020 to 0.0060%, O: 0.0010% to 0.0035%, Nb: 0% to 0.020%, V: 0% to 0.030%, Cr: 0% to 0.50%, Mo: 0% to 0.50%, Cu: 0% to 0.25%, Ni: 0% to 0.50%, B: 0% to 0.0030%, S: limited to 0.010% or less, P: limited to 0.015% or less, Al: limited to 0.004% or less, and a balance consisting of iron and unavoidable impurities, wherein an index value CeEB is 0.49% to 0.60%, a number of oxides having an equivalent circle diameter of 1.0 &#x3bc;m or more is 20 pieces/mmor less, and a number of oxides having an equivalent circle diameter of 0.05 &#x3bc;m or more and less than 0.5 &#x3bc;m is 1&#xd7;10pieces/mmto 1&#xd7;10pieces/mmat a thickness center portion.

Electron-beam welded joint, steel for electron-beam welding, and manufacturing method

The present invention provides a common rail formed by bonding a common rail body and a common rail holder which has a pressing surface and a convex bonding surface, by means of a heat pressure bonding process and a liquid phase diffusion bonding process, wherein the height H of the convex bonding surface satisfies 1 &#x3bc;m&#x2266;H&#x2266;50 &#x3bc;m, and the common rail holder includes a deformation introducing portion in which an area of a cross-section parallel to the pressing surface is smaller than the area of the pressing surface.

Common rail, common rail holder, and method of producing common rail

The present invention provides a high strength steel having unprecedentedly superior CTOD (fracture toughness) properties satisfying not only the CTOD properties of the FL zone at &#x2212;60&#xb0; C., but also the CTOD properties of the ICHAZ zone in small and medium heat input multilayer welding, etc.; and a method of production of the same. The steel of the present invention is steel superior in CTOD properties of the heat-affected zone containing, by mass %, C: 0.015 to 0.045%, Si: 0.05 to 0.2%, Mn: 1.5 to 2.0%, Cu: 0.25 to 0.5%, Ni: 0.7 to 1.5%, P: 0.008% or less, S: 0.005% or less, Al: 0.004% or less, Ti: 0.005 to 0.015%, Nb: 0.005% or less, O: 0.0015 to 0.0035%, and N: 0.002 to 0.006%, P: 0.065 or less, CeqH: 0.235 or less and the balance consisting of Fe and unavoidable impurities.

Steel superior in CTOD properties of weld heat-affected zone and method of production of same

A method of production of 780 MPa class high strength steel plate excellent low temperature toughness comprising heating a steel slab of containing, by mass %, C: 0.06 to 0.15%, Si: 0.05 to 0.35%, Mn: 0.60 to 2.00%, P: 0.015% or less, S: 0.015% or less, Cu: 0.1 to 0.5%, Ni: 0.1 to 1.5%, Cr: 0.05 to 0.8%, Mo: 0.05 to 0.6%, Nb: less than 0.005%, V: 0.005 to 0.060%, Ti: less than 0.003%, Al: 0.02 to 0.10%, B: 0.0005 to 0.003%, and N: 0.002 to 0.006% to 1050&#xb0; C. to 1200&#xb0; C. in temperature, hot rolling ending at 870&#xb0; C. or more, waiting for 10 seconds to 90 seconds, then cooling from 840&#xb0; C. or more in temperature by a 5&#xb0; C./s or more cooling rate to 200&#xb0; C., then tempering at 450&#xb0; C. to 650&#xb0; C. in temperature for 20 minutes to 60 minutes.

Method of production of 780 MPa class high strength steel plate excellent in low temperature toughness

In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by a fluorescent X-ray analysis method using an energy dispersion type spectroscope, or by other chemical or physical measurements, to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Evaluation apparatus for cleanliness of metal and method thereof

In order to quickly and economically evaluate cleanliness of a metal with high representativity when quantities, compositions, etc., of non-metallic inclusion particles existing in a metal and resulting in product defects are evaluated by a sample collected during the production process of the metal, the present invention provides an evaluation method involving the steps of levitation-melting a metal piece for a predetermined time by cold crucible levitation-melting means, discharging non-metallic inclusion particles contained in the metal piece to the surface of a molten metal, and directly analyzing a curved and non-smooth sample surface after solidification by dissolving the surface and extracting and filtering the inclusions to measure or analyze the quantities of elements constituting the non-metallic inclusion particles and to determine quantity of the non-metallic inclusions.

Evaluation method for cleanliness of metal

Steel having improved toughness in welding heat-affected zone

A Ti-Al intermetallic compound is prepared from a mixture of about 40 to 52 atomic % Ti, about 48 to 60 atomic % Al, and 10 to 3000 atomic ppm of at least one of P, As, Se, or Te. The mixture is melted and then solidified. The solidified product is annealed to form a uniform microstructure.

Process for the preaparation of a Ti-Al intermetallic compound

A Ti--Al intermetallic compound has a compressibility of at least 25% at room temperature and a superior high temperature oxidation resistance and consists essentially of about 40 to 52 atomic percent of Ti, about 48 to 60 atomic percent of Al, and 10 to 1000 atomic ppm of at least one of P, As, Se, or Te.

Growing community of inventors

Tokyo, Japan

Ryuji Uemori