Hitachi, Ltd.

Hitachi-ge Nuclear Energy, Ltd.

Yukio Hirama

Kenichi Yasuda

Yoshio Takakura

Tsuyoshi Ito

Makoto Nagase

Hideyuki Hosokawa

Mitsuo Nihei

Kenjiro Narita

Kouji Satou

Toshiyuki Kajiwara

Shinichi Kaga

Motoaki Sakashita

Koji Sato

Tadashi Nishino

Yasutsugu Yoshimura

Masatoshi Watanabe

Hiroyuki Shiraiwa

Yasuyuki Wachi

Ken-ichi Yasuda

Yasuhiro Yasaka

Takashi Norikura

Takehiko Saito

Hidekazu Tabata

Minoru Igari

Shigeo Higuchi

Tsutomu Iwasaki

Yasutsuga Yoshimura

Ken-ichi Yoshimoto

Norihito Satou

Both ends of a circulation pipe of a film formation apparatus are connected to a piping of a BWR plant. A chemical including chromium ions and formic acid is injected into a film formation solution flowing in the circulation pipe heated to a temperature within a range from 60&#xb0; C. to 100&#xb0; C. Furthermore, a chemical including iron (II) ions and formic acid, hydrogen peroxide, and hydrazine are injected into the circulation pipe. Due to the injection of these chemicals, a film formation solution of pH 7.0 including iron (II) ions, chromium ions, formic acid, hydrogen peroxide, and hydrazine is generated in the circulation pipe. This film formation solution includes hydrazine of, for example, 1000 ppm. The film formation solution is supplied to the piping, thus, a Fe&#x2014;CrOfilm (here, 0&#x3c;X&#x2266;0.1) is formed on the inner surface of the piping. The above method of forming the ferrite film on a structural member (for example, the piping) can be shortened time required to form the ferrite film.

[object Object]

A bath containing nickel ions and formic acid is injected into a film-forming aqueous solution flowing in a circulation pipe connected to feed water pipe made of carbon steel in a BWR plant. This film-forming aqueous solution is supplied into the feed water pipe through the circulation pipe, and then, a nickel metal film is formed on an inner surface of the feed water pipe. After the nickel metal film is formed, a film-forming aqueous solution containing iron (II) ions, formic acid, nickel ions, hydrogen peroxide, and hydrazine is supplied to the feed water pipe. A nickel ferrite film is formed on the surface of the nickel metal film in the feed water pipe. Then, the nickel ferrite film is come into contact with water containing dissolved-oxygen at 150&#xb0; C. or above to transform the nickel metal film into a nickel ferrite film. A thick nickel ferrite film is formed on the inner surface of the feed water pipe. Corrosion of the carbon steel member composing the plant can further reduce.

Suppression method for corrosion of carbon steel member

A bath containing nickel ions and formic acid is injected into a film-forming aqueous solution flowing in a circulation pipe connected to a feed water pipe made of carbon steel in a BWR plant. This solution is supplied into the pipe through the circulation pipe, and a nickel metal film is formed on an inner surface of the pipe. After the film is formed, a film-forming aqueous solution containing iron (II) ions, formic acid, nickel ions, hydrogen peroxide, and hydrazine is supplied to the pipe. A nickel ferrite film is formed on the surface of the nickel metal film in the pipe. The nickel ferrite film comes into contact with water containing dissolved oxygen at or above 150&#xb0; C. to transform the nickel metal film into a nickel ferrite film. A thick nickel ferrite film is formed on the inner surface of the feed water pipe.

To improve the productivity of the cold rolling facility by providing the cold rolling facility with a strip wiper free of dust and foreign matters suitable for high-speed rolling. The wiping ability was greatly improved by floating and supporting the wiper roll by the static pressure bearing of air of two-pocket type, and by variably adjusting the load range of the floating force in response to the plate width. At high-speed rolling exceeding 700 m/min which was incapable with the conventional roll wiper or tube wiper, the productivity of the cold rolling facility and the surface quality of the strip were greatly improved by applying to the cold rolling facility the wiping device whose wiping ability is equal to or better than the tube wiper at low speeds, and its effect is very large.

Strip wiper device, strip wiping method, rolling mill and rolling method

The invention intends to always maintain a distance between a hydrostatic pressure bearing and a roll even in a transient state before and after the start of rolling, thereby sufficiently and surely preventing damage of those components upon contact with each other, and to prevent a lowering of yield. In a plate rolling mill comprising upper and lower work rolls, and hydrostatic pressure bearings for supporting barrel portions of idler rolls in a non-contact manner with fluid pressure substantially along the horizontal direction, the idler rolls supporting the work rolls substantially along the horizontal direction, gap restraining rolls are provided to prevent gaps between the hydrostatic pressure bearings and the idler rolls from becoming lower than a predetermined value.

Plate rolling mill

A rolling mill is provided with a pair of work rolls 2, a pair of intermediate rolls 3 and a pair of backup rolls 4 in a mill stand 5, wherein the pair of backup rolls are arranged so that their axial lines cross perpendicularly a plate travelling direction and do not incline to the direction in a horizontal plane, the intermediate rolls and work rolls are arranged so that the axial lines of the intermediate rolls and the axial line of the work rolls incline to (cross) the axes of the backup rolls in a counter direction to each other in a horizontal plane, and a lubricant supplying apparatus 6 is provided for supplying a lubricant to the roll surfaces.

Rolling mill and rolling method

To provide a rolling mill in which work rolls being supported horizontally by static pressure bearings wherein, even under the action of an excessive horizontal force, preventing contact between the work rolls and the static pressure bearings to ensure the production of a strip product free of flaw and superior in its surface quality. Work rolls are supported by static pressure bearings through idler rolls. The amount of offset of the work rolls are changed respectively by moving devices through static pressure bearings. Further, pushing cylinders generate a certain force through the static pressure bearings to bear the force provided from the moving devices.

In a tandem mill system, at least one first type rolling mill is arranged in the upstream side and at least one second type rolling mill is arranged in the downstream side. The first type rolling mill is of the so-called work roll crossing mill in which a pair of work rolls are inclined with respect to a pair of back-up rolls supporting the work rolls and simultaneously crossed each other in a horizontal plane to control transverse thickness distribution of a strip. The second type rolling mill is of the so-called HC mill which controls the strip crown and shape by a combination of axial movement of intermediate rolls and work roll bending. Such an arrangement makes it possible to increase a capability of controlling the strip crown and shape, particularly, a capability of correcting the quarter buckle, and eliminate a fear of causing scratches on the strip and roll surfaces, with the result of improved production efficiency. Plural lines of lubricant supply device are also provided to stop supply of a lubricant immediately before biting of the strip into the work roll crossing mill and start the supply again after the biting. A system of lubricating the work roll crossing mill is thereby improved.

Tandem mill system and work roll crossing mill

In a system and method for manufacturing thin plate by hot-working, a splicing machine for continuously splicing the front edge of a following plate and the rear edge of a precedent plate is provided in the process precedent to a set of rolling mill stands having non-driven small diameter working rollers. By continuously splicing the plates, most portions of the rolled plates can be rolled under a steady state rolling condition, that is, an after-engaged rolling condition, and the thickness reducing amount of the plates in most portions of the rolled material is substantially increased, which substantially improves the rolling efficiency. Thereby, the diameter of the working rollers can be decreased smaller than the diameter of working roller used in a conventional rolling mill, rolling mill strands can be made small, and it can be realized to attain a small-scale system for manufacturing thin plate by hot working.

System and method for manufacturing thin plate by hot working

A rolling mill has a work roll and a back-up roll for supporting the work roll vertically and driving it. A plurality of horizontal support rollers contact the work roll at barrel diameter outside the rolling region and at a both horizontal sides of the work roll and act to fix the position of the work roll in both horizontal directions during rolling and to oppose horizontal rolling forces. In order to reduce the bending of the work roll during rolling, there are provided means for applying horizontal counterbending forces to the work roll comprising members e.g. rollers, contacting the work roll at locations axially further from the rolling region than the support rollers and actuator means for urging the members against the work roll. The counterbending forces being in the same direction as the net horizontal force applied to said work roll by said back-up roll and the material being rolled. Preferably at least one condition of said work roll is sensed during rolling, and there are control means acting during rolling to control the counterbending forces in dependence on the sensed condition.

A rotor for electric rotating machines has a plurality of salient poles arranged in spaced relation in axial direction on the outer periphery of the rotor rim. Adjacent salient poles have opposed slots in the axial direction, into which a shielding member is fitted to bridge between said adjacent poles. The shielding member includes a plurality of rod members fitted over the entire length of said slots to extend across said opposed slots. While the rotor is running, the centrifugal force acts on each of said rod members thereby pressing the rod members against the outer periphery side wall of the slot. As a result, the centrifugal force is dispersed substantially uniformly over the entire length of the slot wall.

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Mito, Japan

Yukio Hirama