Abstract: Provided is a threaded joint for an oil well tubing which possesses sufficient sealability when the external pressure is applied to the threaded joint by suppressing the plastic deformation of a nose portion and sufficient galling resistance. The sufficient galling resistance is provided by preventing the occurrence of galling at the time of making up the threaded joint during verification test performed in accordance with ISO13679:2002 even when the threaded joint for an oil well tubing has a small thickness. Parameters including sizes of the threaded joint at positions of a seal point and shoulder portions satisfy formula 1 ((Ds12?Ds02)/(D12?D02)?0.30), formula 2 (tan ?>(?D+?)/{2(Lt?Ls)}), and Ls/Ln is set to 0.2 to 0.6.

Abstract: A threaded joint for pipes including a pin and a box, characterized in that the relationship 0.05 degrees??sb??sp?2.0 degrees is satisfied, where ?sb is an angle of an insertion surface of the female thread on the box side relative to a plane perpendicular to an axis of pipe, and ?sp is an angle of an insertion surface of the male thread, which faces the insertion surface of the female thread, on the pin side relative to the plane perpendicular to the axis of pipe.

Abstract: A threaded joint is adapted for tubes where the stress or the strain concentration hardly occur at a threaded corner portion of box side even when the threaded joint receives repeated tensile-compressive forces or repeated bending forces. In a radial seal type threaded joint, tensile efficiency TE (%) defined by a ratio Sc/Sp between a cross-sectional area Sc, an area of Critical Cross Section (CCS) including a portion where a tensile stress and a strain become the highest in a tube circumferential cross section of a box and a cross-sectional area Sp of a tube body satisfies formula TE (%)?2.25×t/?+99.9 having a ratio t/? between an internal thread height t of the box and a radius of curvature ? of a corner portion of internally-threaded bottom load surface side.

Abstract: Provided is a threaded joint for an oil well tubing which possesses sufficient sealability when the external pressure is applied to the threaded joint by suppressing the plastic deformation of a nose portion and sufficient galling resistance. The sufficient galling resistance is provided by preventing the occurrence of galling at the time of making up the threaded joint during verification test performed in accordance with ISO13679:2002 even when the threaded joint for an oil well tubing has a small thickness. Parameters including sizes of the threaded joint at positions of a seal point and shoulder portions satisfy formula 1 ((Ds12?Ds02)/(D12?D02)?0.30), formula 2 (tan ?>(?D+?)/{2(Lt?Ls)}), and Ls/Ln is set to 0.2 to 0.6.

Abstract: In a joint for oil country tubular goods, a pitch change is made such that an internally-thread pitch has the same value as an externally-thread pitch from a thread end portion on a box end side to a pitch change position taken on a box center side with respect to a position away from the thread end portion by ½ of an entire length of the threaded portion, and the internally-thread pitch is changed to a value less than the externally-thread pitch at the pitch change position so that a thread gap is gradually decreased from the pitch change position to a position of the thread end portion on the box center side, and the thread gap is eventually set to a value which is 0.2 to 0.8 times as large as the thread gap before the pitch change is made.

Abstract: A screw joint for a pipe comprising (1) a pin member, the raw pipe portion of which has an outer diameter set to 168.

Abstract: A premium threaded joint has a pin-side shoulder angle ?1, a box-side shoulder angle ?2, a seal interference quantity ? and a seal point distance xp satisfying ?2??1=?×?/xp, ?=7 to 14, and a pin distal end thickness tp1 defined by a difference Re?Ri between a radius Re of a pin most distal end portion and an inner radius Ri of a pin distal end portion is 0.25 times or more as large as a pin raw pipe thickness tp0.

Abstract: A threaded joint for an oil country tubular goods includes pins each of which occupies a pipe end portion of a steel pipe for an oil country tubular goods, and includes an externally-threaded portion, a nose extending toward a pipe end side from the externally-threaded portion, and a shoulder forming a distal end of the nose; and a box including internally-threaded portions each forming a threaded portion by being threadedly joined with the externally-threaded portion, and shoulders brought into contact with the shoulders of the pins, wherein the pins and the box being joined to each other by the threaded joining so that portions between the threaded portions and the shoulders are brought into metal-to-metal contact with each other to thereby form seal portions at the contact portions, and the shoulders of the pins and the shoulders of the box forming shoulder faces are brought into contact with each other at the time of make-up of the threaded joint, and a ratio of a chamfer length of pin thread to a thread

Abstract: A threaded joint for heavy-walled oil country tubular goods can both ensure sealability and prevent galling in a state where a high external pressure is also applied to the threaded joint in addition to a high compressive force. A surface of a pin side forming a seal portion and a surface of a box side forming a seal portion are formed into a convex curved surface and a tapered surface, respectively. A seal thickness ts of the pin is 15 mm or less, a shape parameter ts/D (D: outer diameter of a pin raw pipe portion) is 0.045 or more, and a complete thread length ratio L/t (L: complete thread length of the pin, t: wall thickness of the pin raw pipe portion) is 4.0 or less.

Abstract: A threaded joint for steel pipes that includes a pin and a box. The pin has an externally threaded portion, a nose, and a shoulder portion. The box has an internally threaded portion, a sealing surface, and a shoulder portion. The outer circumferential surface of the nose of the pin has an outward convex curved shape, and the sealing surface of the box has a tapered shape. Additionally, the cross-sectional area of the pin at a seal point is 35% or more of the cross-sectional area of an original pipe portion corresponding to an unprocessed portion of the pin, the seal point being a portion on the pin that first comes into contact with the sealing surface of the box when the pin and the box are joined.

Abstract: A threaded joint is adapted for tubes where the stress or the strain concentration hardly occur at a threaded corner portion of box side even when the threaded joint receives repeated tensile-compressive forces or repeated bending forces. In a radial seal type threaded joint, tensile efficiency TE (%) defined by a ratio Sc/Sp between a cross-sectional area Sc, an area of Critical Cross Section (CCS) including a portion where a tensile stress and a strain become the highest in a tube circumferential cross section of a box and a cross-sectional area Sp of a tube body satisfies formula TE (%)?2.25×t/?+99.9 having a ratio t/? between an internal thread height t of the box and a radius of curvature ? of a corner portion of internally-threaded bottom load surface side.

Abstract: A threaded joint for heavy-walled oil country tubular goods can both ensure sealability and prevent galling in a state where a high external pressure is also applied to the threaded joint in addition to a high compressive force. A surface of a pin side forming a seal portion and a surface of a box side forming a seal portion are formed into a convex curved surface and a tapered surface, respectively. A seal thickness ts of the pin is 15 mm or less, a shape parameter ts/D (D: outer diameter of a pin raw pipe portion) is 0.045 or more, and a complete thread length ratio L/t (L: complete thread length of the pin, t: wall thickness of the pin raw pipe portion) is 4.0 or less.

Abstract: In the threaded joint for pipes, a coating having a Vickers hardness greater than or equal to 310 is formed on a threaded portion of the box and an inner face of the box corresponding to a seal portion. The seal interference amount ratio ?/D of the seal portion in a pipe circumferential direction is greater than or equal to 0.002, where D is a seal diameter defined as an outside diameter of the pin at a seal point that is a point on the outer peripheral face of the nose of the pin at which the outer peripheral face first comes into contact with the inner peripheral face of the nose of the box and ? is an interference amount defined as an amount by which the outside diameter at the seal point is reduced by the box when the pin and the box are threadedly connected with each other.

Abstract: A premium threaded joint has a pin-side shoulder angle ?1, a box-side shoulder angle ?2, a seal interference quantity ? and a seal point distance xp satisfying ?2??1=?×?/xp, ?=7 to 14, and a pin distal end thickness tp1 defined by a difference Re?Ri between a radius Re of a pin most distal end portion and an inner radius Ri of a pin distal end portion is 0.25 times or more as large as a pin raw pipe thickness tp0.

Abstract: In a joint for oil country tubular goods, a pitch change is made such that an internally-thread pitch has the same value as an externally-thread pitch from a thread end portion on a box end side to a pitch change position taken on a box center side with respect to a position away from the thread end portion by ½ of an entire length of the threaded portion, and the internally-thread pitch is changed to a value less than the externally-thread pitch at the pitch change position so that a thread gap is gradually decreased from the pitch change position to a position of the thread end portion on the box center side, and the thread gap is eventually set to a value which is 0.2 to 0.8 times as large as the thread gap before the pitch change is made.

Abstract: A threaded joint for an oil country tubular goods includes pins each of which occupies a pipe end portion of a steel pipe for an oil country tubular goods, and includes an externally-threaded portion, a nose extending toward a pipe end side from the externally-threaded portion, and a shoulder forming a distal end of the nose; and a box including internally-threaded portions each forming a threaded portion by being threadedly joined with the externally-threaded portion, and shoulders brought into contact with the shoulders of the pins, wherein the pins and the box being joined to each other by the threaded joining so that portions between the threaded portions and the shoulders are brought into metal-to-metal contact with each other to thereby form seal portions at the contact portions, and the shoulders of the pins and the shoulders of the box forming shoulder faces are brought into contact with each other at the time of make-up of the threaded joint, and a ratio of a chamfer length of pin thread to a thread

Abstract: A threaded joint for pipes including a pin and a box, characterized in that the relationship 0.05 degrees??sb??sp?2.0 degrees is satisfied, where ?sb is an angle of an insertion surface of the female thread on the box side relative to a plane perpendicular to an axis of pipe, and ?sp is an angle of an insertion surface of the male thread, which faces the insertion surface of the female thread, on the pin side relative to the plane perpendicular to the axis of pipe.

Abstract: A threaded joint for pipes is provided in which a box-side lip length L, which is the axial distance between a pin-nose-end corresponding point P of the box component 1 and a load surface 18b of a lip-side internal thread ridge 50 closest to the pin-nose-end corresponding point P, is 300 or more times as long as an insertion surface interval ?, which is the axial interval between an insertion surface 19b of an internal thread ridge at a position two or more ridges backwards from the lip-side internal thread ridge 50 and an insertion surface 19a of an external thread ridge facing the insertion surface 19b when tightened, that is, L?300×?.

Abstract: Provided is a threaded joint for steel pipes having high sealability even under a bending load. In the threaded joint, when a pin 3 and a box 1 are threadedly connected with each other, the outer peripheral face of a nose 8 of the pin and the inner peripheral face of a nose of the box are in metal-to-metal contact with each other at a contact portion and the contact portion serves as a seal portion 20. A threaded portion, at which the externally threaded portion 7 and the internally threaded portion 5 are threadedly connected with each other, has a negative load flank angle ?, shoulder portions 12 and 14 have a negative torque shoulder angle ?, and the ratio L/d0 of a length L of the nose and a pipe outside diameter d0 is equal to or higher than 0.08.

Abstract: A highly compressible iron powder for powder metallurgy has an optimized particle size distribution. The Vickers microhardness of the particles that do not pass through the sieve having the nominal opening of 150 ?m is controlled to be at most about 110. The iron powder is suitable for production of magnetic parts having high magnetism and mechanical parts having high mechanical strength.