Abstract: A mandrel 10 for 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 shank 14, a connection mechanism 15 and a mandrel ball 16. In a cross-section orthogonal to an axial direction of the mandrel ball 16 at a central position in the axial direction of the mandrel ball 16, the mandrel ball 16 has a first position 19 and a second position 20 at which a first straight line m that passes through a mandrel ball center 17 meets an outer periphery 21 of the mandrel ball. Further, a ratio (L1/L2) between a dimension L1 from the mandrel ball center 17 to the first position 19 and a dimension L2 from the mandrel ball center 17 to the second position 20 is in a range of 0.915 to 0.976.

Abstract: A soft magnetic iron alloy sheet has a saturation magnetic flux density comparable to that of Permendur, with the same iron loss as electromagnetic pure iron, and a lower cost than Permendur. The soft magnetic iron alloy sheet includes, as a chemical composition, 30 at % or less of Co, 0.1 at % or more and 11 at % or less of N, and 1.2 at % or less of vanadium, with the remainder being Fe and impurities. In a thickness direction of the soft magnetic iron alloy sheet, a surface layer region has an average nitrogen concentration of 1 at % or more and 15 at % or less and an internal region has a lower average nitrogen concentration than the surface layer region. In the surface layer region, a thickness is 1% or more and 30% or less from both main surfaces of the sheet and iron-nitride martensite having a tetragonal structure is formed.

Abstract: 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.

Abstract: A mandrel 10 for 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 14, a connection mechanism 15 and a mandrel ball 16. In a cross-section orthogonal to an axial direction of the mandrel ball 16 at a central position in the axial direction of the mandrel ball 16, the mandrel ball 16 has a first position 19 and a second position 20 at which a first straight line m that passes through a mandrel ball center 17 meets an outer periphery 21 of the mandrel ball. Further, a ratio (L1/L2) between a dimension L1 from the mandrel ball center 17 to the first position 19 and a dimension L2 from the mandrel ball center 17 to the second position 20 is in a range of 0.915 to 0.976.

Abstract: A mandrel 10 for 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 14, a connection mechanism 15 and a mandrel ball 16. In a cross-section orthogonal to an axial direction of the mandrel ball 16 at a central position in the axial direction of the mandrel ball 16, the mandrel ball 16 has a first position 19 and a second position 20 at which a first straight line m that passes through a mandrel ball center 17 meets an outer periphery 21 of the mandrel ball. Further, a ratio (L1/L2) between a dimension L1 from the mandrel ball center 17 to the first position 19 and a dimension L2 from the mandrel ball center 17 to the second position 20 is in a range of 0.915 to 0.976.

Abstract: 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.

Abstract: A mandrel 10 for 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 14, a connection mechanism 15 and a mandrel ball 16. In a cross-section orthogonal to an axial direction of the mandrel ball 16 at a central position in the axial direction of the mandrel ball 16, the mandrel ball 16 has a first position 19 and a second position 20 at which a first straight line m that passes through a mandrel ball center 17 meets an outer periphery 21 of the mandrel ball. Further, a ratio (L1/L2) between a dimension L1 from the mandrel ball center 17 to the first position 19 and a dimension L2 from the mandrel ball center 17 to the second position 20 is in a range of 0.915 to 0.976.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A novel type of carbon filaments grow from a purified graphite material when the purified graphite material is heated in a plasma. The carbon filaments thus obtained can be converted into softer graphite filaments. Both the carbon filaments and the graphite filaments as such are extremely useful due to their excellent mechanical strengths. In addition, from each of them, intercalation compounds with an alkali metal can be obtained, which are useful not only as a highly conductive material but also as a catalyst for various reactions.