Abstract: A pregrouted PC steel material (10) includes a 19-wire-twisted PC strand (1), a pregrouted layer (2) disposed on an outer periphery of the PC strand (1), and a sheath (3) configured to cover an outer periphery of the pregrouted layer (2). A filling resin (4) is filled between steel wires (side wires) (1b, 1c, 1d). Since the filling resin (4) does not exude to the pregrouted layer (2) before tensioning of the PC strand (10), an operation of tensioning the PC strand (1) is not hindered by curing of the pregrouted layer (2). In contrast, since the gap between the steel wires is reduced when the PC strand (1) is tensioned, the filling resin (4) flows out (exudes) from between the steel wires to the pregrouted layer (2) to cure the pregrouted layer (2) only after the reduction.

Abstract: A steel wire for a spring has Ca or Na adhered thereto in an amount of 0.2 g/m2 or less.

Abstract: Provided is a pregrouted PC steel material comprising a PC steel stranded wire composed of a plurality of steel wires, a pregrout layer disposed on the outer periphery of the PC steel stranded wire so as to accommodate the PC steel stranded wire, a sheath covering the outer periphery of the pregrout layer, and a capsule including a pregrout-hardening agent and a film with which the agent is covered, the capsule being interposed among the steel wires constituting the PC steel stranded wire. The capsule has a strength such that the capsule is not broken before tensioning the PC steel stranded wire but is broken by a tensile force during the tensioning. Also provided is a method for hardening the pregrout layer.

Abstract: An object of the present invention is to improve machining speed by realizing both conductive properties and discharge performance with regard to an electrode wire for wire electric discharge machining, the electrode wire being obtained by plating a steel wire with a copper-zinc alloy. Another object is to suppress the occurrence of separation, cracking, and the like of plating in a wire-drawing step of an electrode wire. An electrode wire for wire electric discharge machining of the present invention includes a steel wire (11) serving as a core wire, and a plating layer (12) that covers the steel wire and that is composed of a copper-zinc alloy, in which an average zinc concentration of the plating layer is 60% to 75% by mass, a conductivity of the plating layer is 10% to 20% IACS, and a wire diameter is 30 to 200 ?m.

Abstract: An object of the present invention is to improve machining speed by realizing both conductive properties and discharge performance with regard to an electrode wire for wire electric discharge machining, the electrode wire being obtained by plating a steel wire with a copper-zinc alloy. Another object is to suppress the occurrence of separation, cracking, and the like of plating in a wire-drawing step of an electrode wire. An electrode wire for wire electric discharge machining of the present invention includes a steel wire (11) serving as a core wire, and a plating layer (12) that covers the steel wire and that is composed of a copper-zinc alloy, in which an average zinc concentration of the plating layer is 60% to 75% by mass, a conductivity of the plating layer is 10% to 20% IACS, and a wire diameter is 30 to 200 ?m.

Abstract: A powder coating composition for PC strand coating which, when used for the coating of a PC strand, can advantageously form a coating film having an even thickness at low cost without causing uneven thickness or stringness is disclosed. The powder coating composition of this invention for PC strand coating is characterized by having a melt viscosity of 3,000-15,000 poise.

Abstract: A tension measurement apparatus that can carry out tension measurement of superior reproducibility with high sensitivity even for a target object of a stranded wire structure is provided. A cylindrical magnetizer arranged to surround a portion of a long magnetic element that becomes the target object of measurement direct-current magnetizes the magnetic element in the longitudinal direction up to the range of approach to saturation magnetization. Using a Hall element (magnetic sensor) arranged in proximity to the magnetic element at the central region in the longitudinal direction of the magnetic domain, the spatial magnetic field intensity in the neighborhood of the surface of the magnetic element, greatly differing corresponding to stress variation, is detected. Based on the detection value, the tension acting on the magnetic element is measured. Accordingly, a measurement result of superior reproducibility with high sensitivity is obtained.

Abstract: Rubber-cord complex 9 having improved wet heat adhesive property between rubber and cord. The rubber-cord complex includes cord 10 comprising drawn plated wire 17 prepared by providing brass plated layer 16E on surface of element wire 15 and drawing the resulting plated wire and rubber 12 vulcanized and bonded to cord 10. The rubber-cord complex 9 has adhesion reaction layer 25 (formed by cross-linking sulfur and copper) between rubber 12 and brass plated layer 16E. Adhesion reaction layer 25 has average thickness of 50-1,000 nm. Interface S between adhesion reaction layer 25 and the rubber has a fractal dimension of 1.001-1.300 in a wet heat deterioration state after being subjected to vulcanization to bond rubber 12 thereto and being held at a temperature of 50-100° C. and a humidity of 60-100% for one hour to 20 days.

Abstract: A rubber-cord complex having an improved wet heat adhesive property between a rubber and a cord comprising a drawn plated wire, and including a metal cord comprising a drawn plated wire prepared by providing a brass plated layer on the surface of an element wire and drawing the resulting plated wire, and a rubber vulcanized and bonded to the cord, wherein in a wet heat deterioration state of the drawn plated wire after being subjected to the vulcanization to bond the rubber thereto and further held under an atmosphere having a temperature of 50 to 100° C. and a humidity of 60 to 100% for one hour to 20 days, the average grain size of crystal grains present in the brass plated layer is not more than 50 nm, and the grain boundary of the crystal grains has a fractal dimension of 1.001 to 1.500.

Abstract: Magnesium-based alloy wire excelling in strength and toughness, its method of manufacture, and springs in which the magnesium-based alloy wire is utilized are made available. The magnesium-based alloy wire contains, in mass %, 0.1 to 12.0% Al, and 0.1 to 1.0% Mn, and is provided with the following constitution. Diameter d that is 0.1 mm or more and 10.0 mm or less; length L that is 1000d or more; tensile strength that is 250 MPa or more; necking-down rate that is 15% or more; and elongation that is 6% or more. Such wire is produced by draw-forming it at a working temperature of 50° C. or more, and by heating it to a temperature of 100° C. or more and 300° C. or less after the drawing process has been performed.

Abstract: Magnesium-based alloy wire excelling in strength and toughness, its method of manufacture, and springs in which the magnesium-based alloy wire is utilized are made available. The magnesium-based alloy wire contains, in mass %, 0.1 to 12.0% Al, and 0.1 to 1.0% Mn, and is provided with the following constitution. Diameter d that is 0.1 mm or more and 10.0 mm or less; length L that is 1000d or more; tensile strength that is 250 MPa or more; necking-down rate that is 15% or more; and elongation that is 6% or more. Such wire is produced by draw-forming it at a working temperature of 50° C. or more, and by heating it to a temperature of 100° C. or more and 300° C. or less after the drawing process has been performed.

Abstract: Magnesium-based alloy wire excelling in strength and toughness, its method of manufacture, and springs in which the magnesium-based alloy wire is utilized are made available. The magnesium-based alloy wire contains, in mass %, 0.1 to 12.0% Al, and 0.1 to 1.0% Mn, and is provided with the following constitution. Diameter d that is 0.1 mm or more and 10.0 mm or less; length L that is 1000 d or more; tensile strength that is 250 MPa or more; necking-down rate that is 15% or more; and elongation that is 6% or more. Such wire is produced by draw-forming it at a working temperature of 50° C. or more, and by heating it to a temperature of 100° C. or more and 300° C. or less after the drawing process has been performed.

Abstract: A method of manufacturing an annular concentric stranded bead cord, wherein, while rotating an annular core at a fixed position in a peripheral direction, a reel, upon which a lateral wire is wound, repeatedly performs a pendulum swinging movement and a perpendicular movement with respect to the annular core, thereby spirally winding the lateral wire upon the annular core to form a sheath layer. When forming the sheath layer, a fulcrum of the pendulum swinging movement of the reel is determined so that, with reference to a tangential line of a circle of the annular core passing through a winding point where the lateral wire is wound upon the annular core, the lateral wire is wound upon the winding point of the annular core within 15 degrees at a position above the tangential line and within a range of 55 degrees at a position below the tangential line.

Abstract: There is provided a strand that can reduce the trouble in constructing an object to which compression force is applied by the strand and that can keep the construction cost down. A strand 1 is placed in a bore hole provided in a wall or roof surface, and is gripped by a wedge in a tensioned state so as to apply a tensile force to the wall or roof surface. The strand 1 of the present invention includes a pipe-shaped member (corrugated tube 11) made of metal, and a plurality of metal wires 12 arranged on the outer periphery of the corrugated tube 11. The metal wires 12 are arranged to surround the corrugated tube 11 on the cross section of the corrugated tube 11.

Abstract: In one aspect, the present disclosure relates to a high-strength prestressing strand having a seven-wire structure in which one core wire and six outer wires are stranded. An external diameter of the strand is from 15.0 mm to 16.1 mm, a total cross-sectional area of the strand is 135 mm2 or more, and a load at 0.2% permanent elongation is 266 kN or more. A relaxation value measured after a 1000-hour relaxation test is 2.5% or lower and a diameter of the core wire is 5.35±0.3 mm and a diameter of the outer wires is 5.15±0.25 mm. The core wire and the outer wires each have a composition of at least 0.90% carbon. The prestressing strand is manufactured by stranding the core wire and outer wires, giving a stretching treatment, and giving a bluing treatment at a temperature of 380° C. or more and 430° C. or less after or at the same time with the stretching treatment.

Abstract: A tension measurement apparatus that can carry out tension measurement of superior reproducibility with high sensitivity even for a target object of a stranded wire structure is provided. A cylindrical magnetizer arranged to surround a portion of a long magnetic element that becomes the target object of measurement direct-current magnetizes the magnetic element in the longitudinal direction up to the range of approach to saturation magnetization. Using a Hall element (magnetic sensor) arranged in proximity to the magnetic element at the central region in the longitudinal direction of the magnetic domain, the spatial magnetic field intensity in the neighborhood of the surface of the magnetic element, greatly differing corresponding to stress variation, is detected. Based on the detection value, the tension acting on the magnetic element is measured. Accordingly, a measurement result of superior reproducibility with high sensitivity is obtained.

Abstract: An annular metal cord includes an annular core portion and an outer layer portion. The annular core portion is formed by connecting together both ends of a first strand material which is made up of six twisted first metal filaments. The outer layer portion is formed by winding spirally a second strand material which is made up of six twisted second metal filaments around the annular core portion. The second strand material is wound at a predetermined winding angle relative to a center axis of the annular core portion, and a winding initiating end portion and a winding terminating end portion are connected together. As a result, the breaking strength of the annular metal cord can be made large, and the production thereof can be facilitated.

Abstract: An annular core stranded bead wire having a reduced weight and offering ease in manufacturing and handling and a vehicle tire using such a bead wire are provided. The annular core stranded bead wire 2 has a metal annular core 11 and a sheath layer 13 constituted of a side wire 12 wound in a spiral pattern around the annular core: the side wire 12 is prepared by wrapping a side wire main body 21 made of aramid fiber with a pair of steel wires 22.

Abstract: The disclosed bead cord which is lightweight and inexpensive and high in formability includes an annular core and a wrap wire helically wrapped around the annular core, the annular core being made of a medium carbon steel or an alloy steel having a lower carbon content and containing specific elements in suitable amounts. The diameter dC of alular core satisfies 1.04?dC/dS?1.30 where dS is the diameter of the wrap wire. The wrap wire has a coil diameter DS which is 0.5 to 1.3 times diameter DC of an annular shape of the annular core. The annular core may be formed with a plating layer of an Al—Zn alloy or a thick plating layer of Zn, or the annular core may be made of stainless steel.

Abstract: Provided is a high-strength stainless steel spring exhibiting a good workability and having a high load characteristic. Thus, the high-strength stainless steel spring of the invention has an chemical component containing 0.04 to 0.08% by mass of C, 0.15 to 0.22% by mass of N, 0.3 to 2.0% by mass of Si, 0.5 to 3.0% by mass of Mn, 16 to 20% by mass of Cr, 8.0 to 10.5% by mass of Ni, 0.5 to 3.0% by mass of Mo, and the balance of Fe and inevitable impurities, and when the average diameter of the coil is represented by D and further the diameter of the steel wire is represented by d in the case that cross sections of the stainless steel wire are in a complete round form or the value obtained by subtracting the average coil diameter from the outer diameter of the coil is represented by d? in the case that the cross sections of the stainless steel wire are in a form other than the complete round form, the spring has a spring index D/d or D/d? of 2 to 6.