The threaded joint includes a pin and a box. The pin includes a taper male thread part, and the box includes a taper female thread part to be engaged with the taper male thread part. The male thread part is divided into a first region on the free end side of the pin, and a second region on the tubular side of the pin along a tube axis direction. The taper ratio of the first region is greater than the taper ratio of the second region. The taper ratio of the first region is greater than the taper ratio of the female thread part. The taper ratio of the second region is equal to or greater than the taper ratio of the female thread part.

A threaded connection partially in a self-locking arrangement includes a first and a second tubular component provided respectively with male and female threaded zone at their respective ends. Only a portion of a first portion with varying thread width of the male threaded zone cooperates by self-locking tightening with only a portion of the second portion with varying thread width of the female threaded zone when made up one into the other. The connection is able to withstand high torques required for special applications such as drilling with casing or intermediate casing.

A threaded connection for steel pipe is provided that improves its internal-pressure sealability while maintaining the high external-pressure sealability of a threaded connection having a nose used in a steel pipe with large diameter and large wall thickness. In a threaded connection for connecting steel pipe bodies each having an outer diameter equal to or larger than 7 inches and a wall thickness equal to or larger than 0.7 inches, Expression (1) in the description is satisfied and t.sub.B/t.sub.L>1.4, where [mm] is the clearance between the outer surface of the pin and the inner surface of the box upon make-up as measured at the borderline between the pin taper surface and the pin round surface, D [inch] is the outer diameter of the steel pipe body, t [inch] is the wall thickness of the steel pipe body, L [mm] is the distance between a pivot point, which is a position, in the region of contact between the pin sealing surface and the box sealing surface, which is closest to the tip of the pin, and the tip of the pin upon make-up as measured along the pipe-axis direction, t.sub.L [mm] is the wall thickness of the pin as measured at the pivot point, and t.sub.B [mm] is the wall thickness of the box as measured at the pivot point.

A connection includes a first tubular member and a second tubular member. The first tubular member has a pin end with threading and a pin face at an outermost end of the pin end of the first tubular member and the second tubular member has a box end with threading and a box face at an outermost end of the box end of the second tubular member. The first tubular member and the second tubular member are configured to connect when the threading of the pin end engages with the threading of the box end. The thickness of the pin face is substantially identical to the thickness of the box face.

A threaded connection for steel pipes having improved sealing performance is provided. A threaded connection (10) for steel pipes includes a pin (10) and a box (20). The pin (10) includes a nose (11), a pin shoulder surface (12), a pin sealing surface (13) and a male thread (14). The box (20) includes a box shoulder surface (22), a box sealing surface (23) and a female thread (24). When the position of the portion of the pin sealing surface (13) that first contacts the inner periphery of the box (20) during make-up defines a seal position (P), the distance between the seal position (P) and the end of the male thread (14) adjacent to the pin sealing surface (13) as measured in the pipe-axis direction is denoted by x, and the distance between the tip of the pin (10) and the end of the male thread (14) adjacent to the pin sealing surface (13) as measured in the pipe-axis direction is denoted by L, then, x/L is not smaller than 0.4 and not larger than 0.55.

A threaded connection includes a first tube having a pin, the pin having pin threads, a circumferential concave outer pin surface, and a pin torque shoulder at a free end, the concave outer pin surface including a pin seal surface and a continuous extension from the pin seal surface to the pin torque shoulder. A second tube has a box, the box has box threads for interacting with the pin threads, a circumferential inner box surface and a box torque shoulder. The inner box surface has a radially inwardly extending box seal surface, the pin seal surface contacts the box seal surface to define a seal. The seal is spaced from the free end when the pin and box torque shoulders contact, the continuous extension continuing from the seal to the pin torque shoulder. A method for making-up a threaded connection is also provided.

There is provided a threaded connection for pipe having an excellent galling resistance and an excellent appearance. A threaded connection for pipe according to the present embodiment includes a pin (3) and a box (4). The pin (3) and the box (4) have contact surfaces (34) and (44) that include thread parts (31) and (41), metal seal parts (32) and (42), and shoulder parts (33) and (43), respectively. The threaded connection for pipe includes a ZnNi alloy plating layer (100) on the contact surface (34) or (44) of at least one of the pin (3) and the box (4). The ZnNi alloy plating layer (100) contains Cu. The Cu content of the ZnNi alloy plating layer (100) is 4.5% by mass or less (zero excluded).

A drill pipe comprises a drill pipe body having a drill pipe body outer diameter and a drill pipe body inner diameter, wherein the drill pipe body outer diameter is from about 5.1-inches to about 5.4-inches and the drill pipe body inner diameter is from about 4.4-inches to about 4.6-inches; and a tool joint comprising a rotary shoulder box connection; wherein the drill pipe has an optimization ratio and wherein the optimization ratio is at least about 0.68 for a production hole from about 7-inches to about 12-inches. Methods of using the drill pipe are also disclosed.

A drill pipe comprises a drill pipe body and a tool joint that comprises a rotary shoulder connection is disclosed. The rotary shoulder connection comprises: a box connection, wherein the box connection has a box outer radius, a box counter bore radius and a box inner radius, and box threads having a box thread form cut along a box taper; a pin connection, wherein the pin connection has a pin outer radius, a pin cylinder radius and a pin nose radius, and pin threads having a pin thread form cut along a pin taper to align with the box threads inside the box connection; and a primary shoulder connection comprising: a primary box shoulder that is angled or curved; and a primary pin shoulder that is angled or curved. Methods of using the drill pipe are also disclosed.

The invention concerns an abutment for a tubular component, said abutment being overlaid with a coating comprising a principal layer constituted by an alloy selected from nickel-phosphorus alloys, copper-nickel alloys and nickel-tungsten alloys. The invention also concerns a tubular component comprising said abutment and a method for producing such an abutment.