Abstract: There are provided: a seamless steel pipe formed from a cylindrical steel material billet through a hot isostatic extrusion step, wherein a depth of a contiguous flaw formed on an inner periphery surface and an outer periphery surface of the steel pipe is 50 ?m or less; a hollow spring obtained by forming a hollow body in a shape of a coil or a bar or a bar with curved part from the seamless steel pipe made of spring steel and applying a surface treatment to the hollow body so that the hollow body has compressive residual stress; and a method for producing seamless steel pipe including: a billet molding step; a first heating step; a hot isostatic extrusion step; a second heating step; an extension step; a third heating step; and a pickling step.

Abstract: Provided is a hollow seamless steel pipe for a spring, including by mass %, C: 0.2 to 0.7%; Si: 0.5 to 3%; Mn: 0.1 to 2%; Cr: more than 0% and 3% or less; Al: more than 0% and 0.1% or less; P: more than 0% and 0.02% or less; S: more than 0% and 0.02% or less; and N: more than 0% and 0.02%: or less, with the balance being iron and inevitable impurities, wherein, an uneven thickness ratio calculated by formula (1) below is 7.0% or less.

Abstract: An alloy material includes: a composition containing 17 at % to 25 at % of silver (Ag), 30 at % to 45 at % of palladium (Pd), and 30 at % to 53 at % of copper (Cu) in a composition range of a ternary alloy of Ag, Pd, and Cu; and at least one of manganese (Mn), tin (Sn), silicon (Si), antimony (Sb), titanium (Ti) and magnesium (Mg) added to the composition in a range of 4.5 at % or less, and the Mn in a range of 0.5 at % to 3.5 at %, the Sn in a range of 1 at % to 2 at %, the Si in a range of 0.5 at % to 2 at %, the Sb in a range of 0.5 at % to 3 at %, the Ti in a range of 0.5 at % to 2 at %, and the Mg in a range of 0.5 at % to 3.5 at % are added to the composition.

Abstract: A hollow seamless pipe for a high-strength spring with reduced occurrence of decarburization in the inner and outer peripheral surfaces, hardened surface layers in the inner and outer peripheral surfaces during quenching, and sufficient fatigue strength is provided. The hollow seamless pipe contains a steel material, which includes 0.2 to 0.7 mass % of C, 0.5 to 3 mass % of Si, 0.1 to 2 mass % of Mn, more than 0 and 0.1 mass % or less of Al, more than 0 and 0.02 mass % or less of P, more than 0 and 0.02 mass % or less of S, and more than 0 and 0.02 mass % or less of N. The C content in the inner and outer peripheral surfaces is 0.10 mass % or more. A thickness of a whole decarburized layer in each of the inner peripheral surface and the outer peripheral surface is 200 ?m or less.

Abstract: A seamless steel pipe for a hollow spring includes C: 0.2 to 0.7 mass %, Si: 0.5 to 3 mass %, Mn: 0.1 to 2 mass %, Cr: 3 mass % or less (excluding 0 mass %), Al: 0.1 mass % or less (excluding 0 mass %), P: 0.02 mass % or less (excluding 0 mass %), S: 0.02 mass % or less (excluding 0 mass %) and N: 0.02 mass % or less (excluding 0 mass %). A residual austenite content in an inner surface layer part of the steel pipe is 5 vol. % or less. An average grain size of a ferrite-pearlite structure in the inner surface layer part of the steel pipe is 18 ?m or less. A number density of a carbide having a circle equivalent diameter of 500 nm or more and being present in the inner surface layer part of the steel pipe is 1.8×10?2 particles/?m2 or less.

Abstract: There are provided: a seamless steel pipe formed from a cylindrical steel material billet through a hot isostatic extrusion step, wherein a depth of a contiguous flaw formed on an inner periphery surface and an outer periphery surface of the steel pipe is 50 ?m or less; a hollow spring obtained by forming a hollow body in a shape of a coil or a bar or a bar with curved part from the seamless steel pipe made of spring steel and applying a surface treatment to the hollow body so that the hollow body has compressive residual stress; and a method for producing seamless steel pipe including: a billet molding step; a first heating step; a hot isostatic extrusion step; a second heating step; an extension step; a third heating step; and a pickling step.

Abstract: A hollow seamless pipe for a high-strength spring in the present invention includes a steel material in which chemical component compositions are properly adjusted, wherein a depth of a whole decarburized layer in an inner surface layer part is 100 ?m or less, a depth of a flaw which is present in an inner surface is 40 ?m or less, a width of the flaw is 60 ?m or less, and a number density of a carbide which has a circle equivalent diameter of 500 nm or more and is present in the inner surface layer part is 1.8×10?2 particles/?m2 or less.

Abstract: A hollow seamless pipe for a high-strength spring in the present invention includes a steel material in which chemical component compositions are properly adjusted, wherein a depth of a whole decarburized layer in an inner surface layer part is 100 ?m or less, a depth of a flaw which is present in an inner surface is 40 ?m or less, a width of the flaw is 60 ?m or less, and a number density of a carbide which has a circle equivalent diameter of 500 nm or more and is present in the inner surface layer part is 1.8×10?2 particles/?m2 or less.

Abstract: An alloy material includes: a composition containing 17 at % to 25 at % of silver (Ag), 30 at % to 45 at % of palladium (Pd), and 30 at % to 53 at % of copper (Cu) in a composition range of a ternary alloy of Ag, Pd, and Cu; and at least one of manganese (Mn), tin (Sn), silicon (Si), antimony (Sb), titanium (Ti) and magnesium (Mg) added to the composition in a range of 4.5 at % or less, and the Mn in a range of 0.5 at % to 3.5 at %, the Sn in a range of 1 at % to 2 at %, the Si in a range of 0.5 at % to 2 at %, the Sb in a range of 0.5 at % to 3 at %, the Ti in a range of 0.5 at % to 2 at %, and the Mg in a range of 0.5 at % to 3.5 at % are added to the composition.

Abstract: A seamless steel pipe for a hollow spring includes C: 0.2 to 0.7 mass %, Si: 0.5 to 3 mass %, Mn: 0.1 to 2 mass %, Cr: 3 mass % or less (excluding 0 mass %), Al: 0.1 mass % or less (excluding 0 mass %), P: 0.02 mass % or less (excluding 0 mass %), S: 0.02 mass % or less (excluding 0 mass %) and N: 0.02 mass % or less (excluding 0 mass %). A residual austenite content in an inner surface layer part of the steel pipe is 5 vol. % or less. An average grain size of a ferrite-pearlite structure in the inner surface layer part of the steel pipe is 18 ?m or less. A number density of a carbide having a circle equivalent diameter of 500 nm or more and being present in the inner surface layer part of the steel pipe is 1.8×10?2 particles/?m2 or less.

Abstract: There are provided: a seamless steel pipe formed from a cylindrical steel material billet through a hot isostatic extrusion step, wherein a depth of a contiguous flaw formed on an inner periphery surface and an outer periphery surface of the steel pipe is 50 ?m or less; a hollow spring obtained by forming a hollow body in a shape of a coil or a bar or a bar with curved part from the seamless steel pipe made of spring steel and applying a surface treatment to the hollow body so that the hollow body has compressive residual stress; and a method for producing seamless steel pipe including: a billet molding step; a first heating step; a hot isostatic extrusion step; a second heating step; an extension step; a third heating step; and a pickling step.

Abstract: The present invention provides a hollow seamless pipe for high-strength springs, in which the occurrence of decarburization in an inner peripheral surface and outer peripheral surface is reduced as much as possible, surface layer parts can be sufficiently hardened in the outer peripheral surface and the inner peripheral surface in a quenching step at the time of spring production, and sufficient fatigue strength can be secured in springs to be formed. The present invention relates to a hollow seamless pipe for a high-strength spring, which is composed of a steel material comprising 0.2 to 0.7 mass % of C, 0.5 to 3 mass % of Si, 0.1 to 2 mass % of Mn, more than 0 mass % and 0.1 mass % or less of Al, more than 0 mass % and 0.02 mass % or less of P, more than 0 mass % and 0.02 mass % or less of S, and more than 0 mass % and 0.02 mass % or less of N, wherein the C content in an inner peripheral surface and outer peripheral surface of the hollow seamless pipe is 0.

Abstract: A method of manufacturing a clad metal column for linear motor, wherein a core material provided with a convex-and-concave pattern consisting of many longitudinal, transverse, or slanted grooves, or the combination thereof on its peripheral surface is inserted into a pipe made of a good conductor, and said pipe is fit tight onto the peripheral surface of above-mentioned core material by the reduction of diameter of pipe by means of drawing or extrusion.