Hitachi, Ltd.

Toshimi Matsumoto

Tsutomu Onuma

Michiya Okada

Takahiko Kato

Kazuhide Tanaka

Yasumasa Tamai

Akira Onuma

Keiichi Uraki

Mitsuo Nakamura

Hiroshi Satoh

Shinpei Matsuda

Toyotaka Yuasa

Katsuzo Aihara

Toshiya Doi

Yoshimi Yanai

Akira Okayama

Tadaoki Morimoto

Hiroo Koide

Toshitaka Satsuta

Tetsuya Nagata

Hideo Suzuki

Hiroshi Sato

Tomoichi Kamo

Toshihide Nabatame

Hisanori Okamura

Yasuhisa Aono

Kunihiko Suzuki

Yukio Saito

Takao Funamoto

Yoshihide Wadayama

Ren Morinaka

Junya Kaneda

Hideyo Kodama

Seishin Kirihara

Shigeo Hattori

Eisaku Hayashi

Fuminori Ishikawa

Kimihiko Akahori

Hiroshi Yamauchi

Yoshiteru Chiba

Masaki Murashita

Tatsuo Yonezawa

Shizuka Shimanuki

Koji Goto

Osamu Matsushima

Junichiro Morisawa

Masami Yada

Masayuki Kurihara

Jun'ya Kaneda

Choichi Asano

Ryou Nishiwaki

Shigeki Ono

This invention provides an oxide-type superconducting flat wire having a critical current density of at least 1,000 A/cm.sup.2, which comprises a Y--Ba--Cu oxide layer having a superconducting property and a silver layer surrounding the oxide layer and has so flat a cross section vertical to the longitudinal direction of the wire that the upper and lower lines between the oxide layer and the silver layers appearing on the cross section having a zone over they are parallel to each other, the thickness of the oxide layer being cold rolled in the range of 0.35 to 0.75 based on the whole thickness of the wire, the whole thickness being 0.2 mm or less, and the metal layer being deformable to follow the shrink deformation of the oxide layer when heat treated to be sintered, but rigid when used. This flat wire is produced by filling a silver-made tube with a Y--Ba--Cu oxide powder having a superconducting property, drawing the tube into a rod wire having a round cross section, then cold rolling the rod wire in the flat wire so that (t.sub.i -t)/t.sub.i .times.100 is equal to or greater than 90%, wherein t.sub.i is the whole thickness of the cross section of the rod wire before the cold rolling and t is the whole thickness of the cold-rolled flat wire, and then heat treating the flat wire to sinter the superconducting oxide.

Superconducting wire and method of producing the same

An underwater laser processing system has a laser torch; a laser torch driving mechanism for changing a laser emission position of the laser torch; and a chamber with one end opened to an external environment, which contains the laser torch; wherein a partitioning wall for preventing permeation of water is provided between a free end of the chamber and the laser torch. The system is used for detecting a sensitized portion and repairing it at one time using a sensitization detecting arrangement. Moreover, it is used for forming an alloying layer by melting a sprayed coating film, and for forming a new surface layer by emitting a laser beam through a solution containing a metal component.

Underwater laser processing device including chamber with partitioning

A submerged laser beam irradiation equipment provides a high quality submerged laser beam processing of a submerged workpiece using only a small amount of a gas. The submerged laser beam irradiation equipment has: a focus lens for focusing a laser beam; a mirror tube which houses the lens; a first nozzle operating to cover the front end of the mirror tube in an irradiating direction of the laser beam; a skirt portion provided at the front end of the first nozzle for preventing water intrusion thereinto; and a shutter mechanism operable to open and close and provided between said skirt portion and said mirror tube for preventing water intrusion into said mirror tube.

Submerged laser beam irradiation equipment

An elongate superconductor wiring element having, as seen in section, oxide superconductor material regions in each of which the c-axes of the oxide superconductor crystals are aligned with each other and are transverse to the longitudinal axis of the element. To reduce the dependence of critical current density on angular position of the element relative to a magnetic field, there are a plurality of said regions whose alignment directions of the c-axes are different as between different ones of said regions, so that the wiring element comprises a plurality of said regions having respectively different c-axis alignment directions.

Elongate superconductor elements comprising oxide superconductors,

A method of performing thermal working to metal material containing helium, which comprises the steps of previously feeding current through a thermally working portion of the metal material containing helium to thereby reduce a helium content in the portion without melting the portion and then heating and melting the portion to improve the defects of the metal structure of the metal material containing helium. As a result, the improvement and removal of defects of the metal structure can be achieved by reducing a helium content in the thermally working portion of the metal material.

Thermal working method of metal material containing helium and thermal

Disclosed is a highly reliable weld repairing method to repair a crack defect in structures and apparatus inside pressure vessels of nuclear reactors, while preventing generation of new crack defects in the structures and apparatus during the repairing. These structures and apparatus are made of any of stainless steel and Ni-base alloys, and are irradiated with high energy corpuscular ray during operating period of the reactor. The repairing method includes the steps of eliminating a region of the structure or the apparatus including a portion having the crack defect, and executing spot welding at a surface of the region continuously or interruptedly in a manner so as to form a first welded layer in a manner that each of the spot welded spots is half-overlapped with adjacent welded spots. Additionally, welding for forming at least a second layer, on the first welded layer, so that the at least a second layer is not deeper than a weld penetration thickness of the first welded layer can be performed.

Method for weld repairing of structures in nuclear reactors

A neutron-irradiated structural material having a defect in a nuclear reactor internals is repaired by covering the structural material to be repaired with a plate to cover over a portion thereof having the defect, and then welding the plate and the structural material by locally applying pressure on the surface of the plate and adding energy to the portion to which the pressure is applied thereby to generate thermal energy in the contact surfaces between the plate and the structural material.

Method of repairing structural materials of nuclear reactor internals

Method of welding a carbon steel and a austenitic stainless steel involves using high density energy beam like a laser beam or electron beam. Welding using high density energy beam is effective to obtain a high precision welding. For the purpose of obtaining both high precision and no cracks, and no deformation, the method of the invention controls the structure of a weld portion to be a mixed structure of an austenitic structure and not greater than 20 wt % of a ferritic structure.

Method of welding a carbon steel and an austenitic stainless steel

A high-temperature oxide superconductor is provided and comprises oxide crystals oriented in a certain direction, the oxide superconductor being substantially free of or containing a controlled amount of foreign phases, a non-superconducting phase and weak superconducting phase which are harmful for superconducting characteristics in the grains of the crystals and at the grain boundaries between the crystals. The foreign phases, if any, are finely and uniformly dispersed in the grains of the oxide crystals and at the grain boundaries. A wire made from the oxide superconductor, a coil from the wire, and a magnetic field generator from the coil are disclosed, the superconductor wire having only a single layer of oxide crystal grains in the thickness direction.

Oxide superconductor, superconducting wire and coil using the same and

The present invention provides a shaped superconductor article such as wire, tape or disk, comprising an oxide superconductor phase and a metal phase in a monolayered or multilayered form, the metal phase comprising a copper, iron, nickel or titanium base alloy containing 1 to 10% by weight of aluminum and having an oxygen-impermeable oxide film formed thereon, preventing the diffusion of oxygen from the oxide superconductor phase to the metal phase.

Ceramic superconductor article

A welded structure and a method for making same wherein a plurality of weld metals, such as martensitic steel and austenitic steel, differing in coefficient of thermal expansion from each other are deposited in a plurality of layers thicknesswise of the welded structure in a gap defined by structural members to be welded in such a manner that a layer of the weld metal of higher coefficient of thermal expansion is covered by a layer of the weld metal of lower coefficient of thermal expansion in a weld formed, to improve brittle fracture strength, fatigue strength and stress corrosion cracking resistance of the weld. By subjecting the welded structure to stress relief annealing treatment, it is possible to produce compressive stress on the surface of the layer of the weld metal of lower coefficient of thermal expansion.

Welded structure having improved mechanical strength and process for

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Hitachinaka, Japan

Toshimi Matsumoto