Hitachi, Ltd.

Hitachi Haramachi Electronics Co., Ltd.

Masahiko Sakamoto

Hisanori Okamura

Kinya Aota

Masakuni Ezumi

Yutaka Fukui

Yasuo Ishimaru

Nobuyuki Iizuka

Takao Funamoto

Hiromi Kagohara

Kouji Satou

Akihiro Sato

Isao Funyu

Kouichi Watanabe

Ryuichi Saito

Makoto Kitano

Nobuya Koike

Noboru Baba

Yoshihiko Koike

Takashi Haramaki

Teruhiro Takizawa

Masahiro Ogihara

Hideya Kokubun

Mituo Nakamura

Hirosi Akiyama

Sigeki Sekine

Chie Sato

Takeshi Yamagiwa

Disclosed is a friction stir welding method for welding two members to be welded which differ in physical properties and/or mechanical properties by abutting the two members to each other, inserting a pin portion of a rotary tool having the pin portion and a shoulder portion to the abutment surfaces of the two members, and moving the rotary tool along the abutment surfaces. The pin portion is inserted to only one of the members, the pin portion is not inserted to the other of the members but only the shoulder portion is set in contact with the other of the members, and, while this condition is maintained, the rotary tool is moved. With this method, only the member on the side where the pin is inserted can be made to undergo plastic flow attendant on a friction stir action. The metal in plastic flow is pressed against the opposite member at an elevated temperature and high pressure, whereby diffusion of atoms is caused in the vicinity of the abutment surfaces, and the members are welded.

Friction stir welding method and component part welded by the method

The invention intends to reduce a frequency at which defects occur in a welding region during friction stir welding, and to improve the reliability of the welding region. The invention resides in a friction stir welding apparatus wherein a distance to the surfaces of the workpieces is detected by a detector, a change of the detected distance is found by a signal processing device, and a tool is rotated by a rotation driving device in a state where a vertical driving device is controlled by a control device so as to suppress the found change, whereby a plastic fluidity of the workpieces is caused to accomplish joining of the workpieces.

Friction stir welding method

Friction stir welding apparatus and method

A high reliability electric power control semiconductor device with a prolonged product lifetime has been provided by successfully suppressing the metal support plate or the metal heat dissipation plate from warping due to the thermal stress during bonding so as to prevent the occurrences of cracks and gaps in the brazing fillers in the bonded layers between the metal heat dissipation plate or the metal support plate and the insulation plate in the semiconductor device comprising the semiconductor elements, metal heat dissipation plate, thermal stress buffer, insulation plate, and the metal support plate, wherein at least one of the metal heat dissipation plate and the metal support plate comprises a copper alloy of which a softening temperature at which a hot hardness of which becomes 1/2 of the hardness at the room temperature is 350.degree. C. or more. Further, in the semiconductor device fabricated by bonding the semiconductor elements via the thermal stress buffer, the heat dissipation plate and the insulation plate onto the metal support plate, the heat dissipation plate comprises a portion having a reduced thickness in the periphery thereof machined by counterboring or the like.

Semiconductor device having thermal stress resistance structure

A superconducting magnetic field generating apparatus, and coil, a superconducting wire, a method of producing a coil and a method of connecting a superconducting wire which are suitable for such a superconducting magnetic field generating apparatus are disclosed. The superconducting magnetic field generating apparatus has a coil of a wound superconducting wire which is composed of superconducting wires with the end portions thereof connected with each other. Each of the superconducting wires is composed of a plurality of superconducting material wires embedded in a stabilizing member. The group of superconducting material wires is embedded at the connecting portion in a state in which the superconducting material wires are densely gathered to the central portion of the stabilizing member and the superconducting material wires are directly in contact with each other. The stabilizing member exists in the central portion of the assembly of the superconducting material wires and the stabilizing members are closely bonded to the superconducting material wires.

Superconducting magnetic field generating apparatus and method of

The present invention provides a method for joining of high-temperature oxide superconductors per se or a high-temperature oxide superconductor and other conductive material through a very simple process. According to this method, the joining is carried out by using an alloy comprising 0.1%-90% by weight of at least one divalent metallic element and the balance as a brazing material and heating and melting the brazing material. The resulting joined body has a joint low in resistance. The divalent metallic element of the alloy is preferably an element of Group IIA or IIB of the Periodic Table or a transition metal.

Joined body of high-temperature oxide superconductor and method of

This invention relates to an improvement on material of a shroud for gas turbines. The material comprises 0.25-0.7 wt % C, 20-35 wt % Cr, 20-40 wt % Ni and balance Fe, and has an austenitic structure. The amount of the .sigma.-phase in this invention is less than 5% and Nv value (Electron Vacancy Number) is less than 2.8.

Shroud for gas turbines

Disclosed in a gas turbine nozzle having a superior thermal fatigue resistance. The gas turbine nozzle is made of a cast alloy consisting essentially of 0.1 to 1 wt % carbon, 0.1 to 2 wt % silicon, 0.1 to 2 wt % manganese, 20 to 35 wt % chromium, 0.001 to 0.1 wt % boron, 5 to 15 wt % of at least one of tungsten and molybdenum, 16 to 35 wt % cobalt and the balance nickel. The alloy has a heat-treated structure in which eutectic carbides and secondary carbides are dispersed in the matrix.

Gas turbine nozzle having superior thermal fatigue resistance

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Hitachi, Japan

Masahiko Sakamoto