Nippon Steel Corporation

Nitto Electric Industrial Co., Ltd.

Shohei Tamura

Masao Abe

Keiji Nakamoto

Hisashi Ichinose

Hidehiro Arita

Sadamitsu Sasaki

Hitoshi Nakazawa

Masaaki Mizumura

Takeshi Sasaki

Keinosuke Iguchi

Satoshi Yumoto

Disclosed is a manufacturing method that can suppress the occurrence of wrinkles and buckling deformation due to bending when bending and cross-sectioning are performed on a tube using a press die. The manufacturing method of the present disclosure includes applying pressure to a bent tube having a curved portion from the outside of the tube to the inside of the tube using a press die, thereby simultaneously performing cross-sectioning of the curved portion and bending of the curved portion to reduce the bend radius of the curved portion.

Hollow shell part manufacturing method

A mandrelfor producing a thin-walled bent tube having a bending portion with high strength and a small radius of curvature by rotary draw bending without either cracks in an outside of bend or wrinkles and buckling in an inside of bend occurring includes a shanka connection mechanismand a mandrel ballIn a cross-section orthogonal to an axial direction of the mandrel ballat a central position in the axial direction of the mandrel ballthe mandrel ballhas a first positionand a second positionat which a first straight line m that passes through a mandrel ball centermeets an outer peripheryof the mandrel ball. Further, a ratio (L/L) between a dimension Lfrom the mandrel ball centerto the first positionand a dimension Lfrom the mandrel ball centerto the second positionis in a range of 0.915 to 0.976.

Mandrel, bent tube, and method and apparatus for producing bent tube

A mandrelfor producing a thin-walled bent tube having a bending portion with high strength and a small radius of curvature by rotary draw bending without either cracks in an outside of bend or winkles and buckling in an inside of bend occurring includes a shank, a connection mechanismand a mandrel ball. In a cross-section orthogonal to an axial direction of the mandrel ballat a central position in the axial direction of the mandrel ball, the mandrel ballhas a first positionand a second positionat which a first straight line m that passes through a mandrel ball centermeets an outer peripheryof the mandrel ball. Further, a ratio (L/L) between a dimension Lfrom the mandrel ball centerto the first positionand a dimension Lfrom the mandrel ball centerto the second positionis in a range of 0.915 to 0.976.

A method of manufacturing a flaring-processed metal pipe from a hollow shell including a plurality of portions having different deformation resistances in a circumferential direction is provided, the method includes: among the plurality of portions, specifying a portion having a relatively small deformation resistance as a low deformation resistance section, and a portion having a relatively large deformation resistance as a high deformation resistance section; and press-fitting a pipe expansion punch into the hollow shell such that a thickness reduction rate of the low deformation resistance section is smaller than a thickness reduction rate of the high deformation resistance section.

Method of manufacturing flaring-processed metal pipe

An electroconductive organic polymer exhibiting outstanding electroconductivity is described, containing an electron acceptor as a dopant, and having electroconductivity of not less than 10.sup.-6 S/cm, substantially comprising a linear polymer having as a main repeating unit thereof a quinonediimine structure represented by formula (III) ##STR1## wherein R represents a hydrogen atom or an alkyl group. This polymer can be obtained by oxidative polymerization of an aniline compound or a water-soluble salt thereof with an oxidizing agent in a reaction medium containing a protonic acid.

Electroconductive organic polymer and method for producing the same

An electroconductive porous film is described comprising a porous film substrate having deposited thereon an electroconductive organic polymer containing an electron acceptor as a doptant, substantially comprising a linear polymer having as a main repeating unit thereof a quinonediimine structure represented by formula (III). ##STR1## wherein R.sub.1 and R.sub.2, which are the same or different, each represents a hydrogen atom or an alkyl group.

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Tokyo, Japan

Shohei Tamura