Abstract: This invention provides an oil-tempered wire having high strength (tensile strength of not less than 1960 MPa) and excellent workability and specifically provides a steel wire for high-strength springs comprising as steel components, in weight percent, C   0.4-0.7% Si   1.2-2.5% Mn   0.1-0.5% Cr   0.4-2.0% Al 0.0001-0.005%, and being limited to P not more than 0.015% and S not more than 0.015%, the balance being Fe and unavoidable impurities, the steel wire having no nonmetallic inclusions of a size greater than 15 &mgr;m, a tensile strength of not less than 1960 MPa, and a yield ratio (&sgr;0.2/&sgr;B) of not less than 0.8 and not greater than 0.9 or a yield ratio (&sgr;0.2/&sgr;B) of not less than 0.8 and an amount of residual austenite of not greater than 6%. This invention also provides a method of producing the steel wire.

Abstract: The present invention provides, at low cost, a valve spring steel having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering. The high strength spring steel comprises, based on weight, 0.65 to 0.85% of C, 1.90 to 2.40% of Si, 0.50 to 1.00% of Mn, 0.70 to 1.30% of Cr, 0.10 to 0.30% of Mo, 0.20 to 0.50% of V, 0.01 to 0.04% of Nb and the balance Fe and unavoidable impurities and is subjected to heating at temperature of 1,050 to 1,250.degree. C. and then to rolling so that carbides in the steel have a size of up to 0.15 .mu.m in terms of equivalent circle. A valve spring having a tensile strength as high as 210 to 240 kgf/mm.sup.2 after oil tempering and stabilized quality can be produced while the material cost is greatly reduced by decreasing costly alloying components as much as possible.

Abstract: The present invention provides a steel wire rod of high strength and a steel wire of high strength excellent in fatigue characteristics used for an extra fine steel wire of high strength and high ductility which is used for a steel cord, a belt cord, and the like for reinforcing rubbers and organic materials such as a tire, a belt and a hose, and for a steel wire of high strength which is used for a rope, a PC wire, and the like. The steel of the present invention comprises, based on mass, 0.7 to 1.1% of C, 0.1 to 1.5% of Si, 0.1 to 1.5% of Mn, up to 0.02% of P, up to 0.02% of S and the balance Fe and unavoidable impurities, and contains nonmetallic inclusions at least 80% of which comprise 4 to 60% of CaO+MnO, 22 to 87% of SiO.sub.2 and 0 to 46% of Al.sub.2 O.sub.3 and have melting points up to 1,500.degree. C.

Abstract: This invention provides high-carbon steel wire rod and wire excellent in drawability and methods of producing the same.The high-carbon steel wire rod or wire is characterized in that it contains, in weight percent, C: 0.90-1.10%, Si: not more than 0.40% and Mn: not more than 0.50%, is limited to P: not more than 0.02%, S: not more than 0.01% and Al: not more than 0.003%, the remainder being Fe and unavoidable impurities, and has a microstructure of, in terms of area ratio, not less than 80% upper bainite texture obtained by two-stepped transformation and an Hv of not more than 450. The high-carbon steel wire rod or wire may additionally contain Cr: 0.10-0.30% as an alloying component.

Abstract: This invention provides bainite wire rod and wire excellent in drawability and methods of producing the same.The bainite wire rod or wire is characterized in that it contains, in weight percent, C : 0.90-1.10%, Si : not more than 0.40% and Mn : not more than 0.50%, if required contains Cr : 0.10-0.30%., and is limited to Al : not more than 0.003%, P : not more than 0.02% and S : not more than 0.01%, the remainder being Fe and unavoidable impurities, and has tensile strength and reduction of area determined by the following equations (1) and (2),TS.ltoreq.85.times.(C)+60 (1)RA.gtoreq.-0.875.times.(TS)+158 (2)whereC : carbon content (wt %),TS : tensile strength (kgf/mm.sup.2), andRA : reduction of area (%).

Abstract: This invention relates to high-carbon steel wire rod and wire excellent in drawability and methods of producing the same.The high carbon steel wire rod or wire excellent in is characterized in that it contains, in weight percent, C: 0.70-1.20%, Si: 0.15-1.00% and Mn: 0.30-0.90%, further contains as alloying components one or both of Al: 0.006-0.100 and Ti: 0.01-0.35%, is limited to P: not more than 0.02% and S: not more than 0.01%, the remainder being Fe and unavoidable impurities, and has a microstructure of, in terms of area ratio, not less than 80% upper bainite texture obtained by two-stepped transformation and an Hv of not more than 450. The high-carbon steel wire rod or wire may additionally contain Cr: 0.10-0.50% as an alloying component.

Abstract: This invention provides bainite wire rod and wire excellent in drawability and methods of producing the same.The bainite wire rod or wire is characterized in that it contains, in weight percent, C: 0.80-0.90%, Si: 0.10-1.50% and Mn: 0.10-1.00%, if required contains Cr: 0.10-1.00%, and is limited to P: not more than 0.02%, S: not more than 0.01% and A1: not more than 0.003%, the remainder being Fe and unavoidable impurities, and has tensile strength and reduction of area determined by the following equations (1) and (2),TS.ltoreq.85.times.(C)+60 (1)RA.gtoreq.-0.875.times.(TS)+158 (2)whereC: carbon content (wt%),TS: tensile strength (kgf/mm.sup.2), andRA: reduction of area (%).

Abstract: This invention relates to high-carbon steel wire rod and wire excellent in drawability and methods of producing the same.The high carbon steel wire rod or wire excellent in is characterized in that it contains, in weight percent, C: 0.80-0.90%, Si: 0.10-1.50% and Mn: 0.10-1.00, is limited to P: not more than 0.02%, S: not more than 0.01% and Al: not more than 0.003%, the remainder being Fe and unavoidable impurities, and has a microstructure of, in terms of area ratio, not less than 80% upper bainite texture obtained by two-stepped transformation and an Hv of not more than 450. The high-carbon steel wire rod or wire may additionally contain Cr: 0.10-1.00% as an alloying component.The high-carbon steel wire rod or wire according to this invention can be drawn to an appreciably higher reduction of area than prior art products and also has improved delamination resistance property.

Abstract: This invention provides bainite wire rod and wire excellent in drawability and methods of producing the same.The bainite wire rod or wire is characterized in that it contains, in weight percent, C: 0.70-1.20%, Mn: 0.30-0.90% and Si: 0.15-1.00%, further contains as alloying components one or both of Al: 0.006-0.100% and Ti: 0.01-0.35%, if required contains Cr: 0.10-0.50%, and is limited to P: not more than 0.02% and S: not more than 0.01%, the remainder being Fe and unavoidable impurities, and has tensile strength and reduction of area determined by the following equations (1) and (2),TS.ltoreq.85.times.(C)+60 (1)RA.gtoreq.-0.875.times.(TS)+158 (2)whereC: carbon content (wt %),TS: tensile strength (kgf/mm.sup.2), andRA: reduction of area (%).

Abstract: The present invention relates to a balanced low-pass filter characterized in comprising a pair of input terminals and a pair of output terminals, wherein a pair of coils is connected in series in a negatively coupled manner between a first input terminal and a first output terminal and a pair of coils is connected in series in a negatively coupled manner between a second input terminal and a second output terminal, the connection point between each pair of coils and each end of each coil opposite to the connection point being connected across to the corresponding point of the corresponding pair of coils, with capacitors therebetween, and the coils being wound on the same bobbin in such a manner that each pair of negatively coupled coils is formed in adjacent winding portions.

Abstract: The present invention is concerned with a method of producing steel wires each having a very small diameter of 0.4 mm or less and a tensile strength of 360 kgf/mm.sup.2 or more wherein a steel material having a composition comprisingC: 0.90 to 1.10% by weight, Si: 0.4% or less by weight, Mn: 0.5% or less by weight, Cr: 0:10 to 0.30% by weight and a balance of iron an unavoidable impurities is subjected to diffusion treatment as desired, thereafter, the steel material is subjected to hot rolling, the hot-rolled steel wire is subjected to drawing, subsequently, the resultant steel rod having a smaller diameter is subjected to a final patenting treatment to give said rod a strength of 140 to 160 kgf/mm.sup.2, and thereafter, it is subjected to drawing with a true strain of 3.50 or more using a die having a die approach angle of 8 to 12 degrees.

Abstract: High-strength steel having excellent hydrogen-induced crack resistance, particularly in an environment of wet hydrogen sulfide and wires made thereof and their assembly, steel pipes, steel bands and shielding wires for marine cable are disclosed. This steel contains 0.40 to 0.70% of C, 0.1 to 1% of Si, 0.2 to 1% of Mn, up to 0.25% of P and up to 0.010% of S, and further, if necessary, 0.008 to 0.050% of Al and the balance of Fe and unavoidable impurities, and has a spheroidized structure. In addition, a flexible sour fluid transport pipe made of the high-strength steel band having the above-described composition and a tensile strength of 50 to 80 kg/mm.sub.2 is also disclosed.