Mitsubishi Denki Kabushiki Kaisha

Sumitomo Metal Industries, Inc.

Renesas Technology Corp.

Nippon Steel Sumitomo Metal Corporation

Ricoh Company, Ltd.

Nippon Steel Corporation

Mitsubishi Hitachi Power Systems, Ltd.

Takashi Nakashima

Tetsuo Yokoyama

Kouichi Kuroda

Atsuro Iseda

Takuya Hanada

Minoru Sakai

Masaaki Igarashi

Hiroshi Yamamoto

Takeshi Miki

Kaori Kawano

Tatsuya Okui

Kenichi Beppu

Hiroyoshi Kuroda

Shunichi Otsuka

Atsushi Tominaga

Tadashi Kawakami

Michihiro Yoshida

Hiroyoshi Sato

Yoshihiro Daito

The production method for producing a rifled tube, which includes a plurality of first helical ribs on its inner surface, includes: a steps of: preparing a steel tube; and producing a rifled tube by performing cold drawing on a steel tube by using a plug which includes a plurality of second helical ribs, the plug satisfying Formulae and:0.08 &#x3c;&#xd7;()&#xd7;/(2&#x3c0;&#xd7;)&#x3c;0.26&#x2003;&#x2003;(1)0.83&#x3c;&#xd7;()&#xd7;/(2&#xd7;)&#x3c;2.0&#x2003;&#x2003;(2)where, W is a width of a groove bottom surface of the helical groove; A is a maximum diameter of the plug; B is a minimum diameter of the plug; N is a number of the second helical ribs; S is the width of the groove bottom surface; and M is a pitch of adjacent second helical ribs.

Method for producing a rifled tube

Provided is a method for producing a double-wall tube with braided wires at its interface in which the braided wires are interposed between an outer-wall and inner-wall blank tubes and then a drawing process is applied so as for the braided wires to be brought into close contact with the inner surface of the outer-wall tube and the outer surface of the inner-wall tube, the method comprising: polishing the inner surface of the outer-wall blank tube and the outer surface of the inner-wall blank tube so that a surface roughness thereof satisfies Ra&#x3c;1.0 &#x3bc;m, followed by interposing the braided wires between the outer-wall and inner-wall blank tubes; performing a sinking drawing process so that the difference of the outer diameter of the resulting double-wall tube relative to a die bore diameter is 0.1 mm to 0.3 mm; and subsequently performing heat treatment. The double-wall tube produced is suitable as a heat-transfer tube.

Method for producing double-wall tube with braided wires at its interface

After an inner wall tube, made of steel or alloy containing not less than 2% of Cr, whose outer surface thereof is machined and/or ground to a thickness of 0.1 mm or more including the scale layer, is inserted into an outer wall tube, made of ferritic steel containing not less than 2% of Cr, in which an oxide scale layer containing Cr and having a thickness of 10 to 30 &#x3bc;m is formed in the inner surface thereof, cold working at an outside diameter reduction rate of 5 to 30% is performed. Similarly cold worked after an inner wall tube having an oxide scale layer on the outer surface thereof, is inserted into an outer wall tube whose inner surface is machined and ground. A double-walled tube made has a uniform gap and an excellent thermal conductivity, and is suitable as materials for SG tubes of future FBR.

Double-walled tube with interface gap and production method therefor

According to a low alloy steel of the present invention, compositional elements thereof are limited, and a metal structure thereof comprises bainite or martensite. Further, proper amounts of Nd inclusions are formed by appropriately selecting timings of deoxidation and Nd addition in melting a steel. Consequently, compatibility between high-temperature creep strength and long-term creep ductility, which is hardly established in conventional steels, can be achieved even in hostile conditions. Accordingly, the low alloy steel of the present invention can be widely applied as the material for the heat-resistant structural member used for a long time under the high-temperature and high-pressure conditions such as power plant boilers, turbines, and nuclear power plants.

Low alloy steel

When a certain file is updated, a document management server determines whether a 'registration state information mail' is set for that file, and after that, performs 'self information mail' setting processing. Computer requests the document management server to transmit an electronic file, and prints and displays the electronic file according to an operation definition corresponding to the file format of the received electronic file. MFP inquires whether the document to be displayed is an electronic file stored in the document management server or an electronic file recorded on an external storage medium. Further, in response to an operation of a touch panel, MFP changes a magnifying power of display data, and rotates an image to change the direction by setting the central position of the rotation to a display center of an image being currently displayed.

Document management server, information terminal apparatus, image forming apparatus, document managing method, and program

Steel tubes for bearing element parts according to the present invention, wherein the specific compositions are limited and an accumulation intensity of {211} face along with an impact property at ambient temperature in the longitudinal direction of steel tube are specified, can be provided as a source material for bearing element parts, which have excellent machinability and fatigue life in rolling contact, being incorporated without adding a free-cutting element specifically nor without reducing productivity since the spheroidizing for the same annealing duration with that of conventional spheroidizing treatment can be applied. Accordingly, by applying a manufacturing method or a cutting-machining method according to the present invention, bearing element parts such as races, rollers and shafts can be produced with less cost and efficiently.

Steel tube for bearing element parts and method of manufacturing as well as machining the same

Cold finished seamless steel tubes are made such that the residual stress F to be generated at the stage of the correction process after cold working is controlled to be 30 MPa or more and the scattering thereof is 30 MPa or less, when measured by Crampton method. Further, by adjusting the average grain size of spheroidized carbides, the dimensional change which emerges in lathe turning of the outside and inside diameter of relevant steel tubes due to the residual strain can be suppressed, and the strict roundness as well as the excellent machinability can be secured at the final processing stage of the work pieces for bearing parts. Consequently, steel tubes with high dimensional accuracy and less dimensional change at the final steps such as lathe turning, heat treatment and the like, can be made for use as bearing parts.

Cold finished seamless steel tubes

A semiconductor device includes a p-silicon substrate, n-epitaxial growth layers on the p-silicon substrate, a field insulating film at the surface of the n-epitaxial growth layer, an npn transistor formed at the n-epitaxial growth layer, an pnp transistor formed at the n-epitaxial growth layer, a DMOS transistor on the n-epitaxial growth layer, and a resistance. The DMOS transistor includes an n-diffusion layer forming a source, a p-type diffusion layer forming a back gate region, a lightly doped n-type diffusion layer forming a drain, and a heavily doped n-diffusion layer forming the drain.

Semiconductor device and method of manufacturing the same

An N type epitaxial layer is formed on a P type silicon substrate. Trenches are created so as to penetrate N type epitaxial layer and so as to reach to a predetermined depth of P type silicon substrate. Thermal oxide films are formed on the sidewalls of trenches. Buried polysilicon films are formed so as to fill in trenches. Thermal oxide films are formed having an approximately constant film thickness ranging from the bottoms to the edges of the openings of trenches so as not to give stress to N type epitaxial layers. Thereby, a semiconductor device wherein a leak current is prevented can be gained.

Semiconductor device with trench isolation having reduced leak current

A semiconductor device allowing reduction in area occupied by a bipolar transistor as well as a method of manufacturing the same are obtained. The semiconductor device includes a substrate, first conductivity type regions, a collector region, base regions and emitter regions. The first conductivity type region is formed on the substrate, and has a main surface. The collector region is formed in the first conductivity type region. The base region is located in the first conductivity type region and on the collector region. The emitter region is located in the first conductivity type region and on the base region. The first conductivity type region is provided with grooves extending to the collector region, and isolation grooves disposed around a vertical bipolar transistor. The grooves are filled with conductors of the second conductivity type. The isolation grooves are filled with isolation conductors of the second conductivity type.

Bipolar transistor with collector diffusion layer formed deep in the substrate

An improved bipolar transistor of BiCMOS is provided to improve the breakdown voltage between a collector and a base. A low concentration diffusion layer is provided at a main surface of a semiconductor substrate at a boundary between an outer perimeter of an external base layer and an end portion of a field oxide film. The low concentration diffusion layer expands from the main surface of the semiconductor substrate toward the inside of the substrate and has a concentration lower than the impurity concentration of the external base layer.

Method of manufacturing a semiconductor device including a bipolar

An bipolar transistor of BiCMOS is provided to improve the breakdown voltage between a collector and a base. A low concentration diffusion layer is provided at a main surface of a semiconductor substrate at a boundary between an outer perimeter of an external base layer and an end portion of a field oxide film. The low concentration diffusion layer expands from the main surface of the semiconductor substrate toward the inside of the substrate and has a concentration lower than the impurity concentration of the external base layer.

Growing community of inventors

Wakayama, Japan

Takashi Nakashima