Nippon Steel Corporation

Vallourec Oil and Gas France

Sadao Douchi

Masaaki Sugino

Yousuke Oku

Yasuhiro Yamamoto

Keita Inose

Xavier Mencaglia

Corey Dufrene

A threaded connection for large diameter steel pipe exhibits high torque resistance and high sealability and, at the same time, provides a shear resistance that suits the size of the steel pipe to be connected. The threaded connection includes a tubular pin provided on a tip of a steel pipe with large diameter, and a tubular boxadapted to be drawn up on the pin as the pin is screwed in. The pin includes a male threadform made with a taper thread. The box includes a female threadform made with a taper thread. Each of the threadforms are wedge threads and have a dovetail-shaped cross section. The male threadform is designed such that the width of the thread in an end region of the male threadform closer to the tip is set to a size corresponding to the size of the pipe body of the steel pipe.

Threaded connection for steel pipe

A threaded connection for steel pipe that provides high torque performance, high tension performance and high sealability is provided. A threaded connectionincludes: a tubular pinincluding a pin shoulder, a male threadand a pin seal; and a tubular boxincluding a box shoulder, a female threadand a box seal. The male and female threadsandare constituted by wedge threads. The pin sealis provided between the pin shoulderand the male thread. The box sealcorresponds to the pin sealand is located on the inner peripheral surface of the box. When the connection is made up, the pin shoulderis spaced apart from the box shoulder. The threaded connectionsatisfies the following expression, (1):3%&#x2264;()/&#x2264;7%&#x2003;&#x2003;(1). In expression (1), LP is the pitch between loading flanksof the male thread, and SP is the pitch between stabbing flanksof the male thread

A threaded connection includes a first and a second tubular component made up one with the other. A male element of the first component includes, on its external peripheral surface, a male inner lip including an inner mg with a minimum thickness Epi and a male threaded zone. One inner end of the male threaded zone is at a non-zero axial distance (Li) from a male distal end. A female element of the second component includes, in succession over its internal peripheral surface, a female inner recess disposed facing the male inner lip and a female threaded zone, such that in the made up position of the connection, a radial clearance subsists between the male inner ring and the female inner recess and an internal seal is formed locally between the male inner lip and the female inner recess. The connection is such that 10%&#x2264;Epi/Li.

Threaded connection for tubular component

A threaded connection for steel pipe that provides both high torque performance and high tension performance is provided. A threaded connectionincludes a tubular pinformed by one tip portion of a steel pipe and a tubular boxadapted to be made up on the pinas the pinis inserted into the box. The pinincludes a male threadprovided on an outer periphery of the pin, the male thread being a wedge thread. The boxincludes a female threadcorresponding to the male threadand provided on the inner periphery of the box, the female thread being a wedge thread. The threaded connectionsatisfies the following expression, (1):3%&#x2264;()/&#x2264;8%&#x2003;&#x2003;(1). In expression (1), LP is the pitch between loading flanksof the male thread, and SP is the pitch between stabbing flanksof the male thread

A threaded connection for steel pipe with improved sealing performance is provided. A threaded connection () for steel pipe includes a pin () and a box (). The outer diameter of the box () is smaller than 108% of the outer diameter of a steel-pipe body (). The pin () includes a pin lip () including a first seal surface (), a male thread () constituted by a single-stage tapered thread, and a second seal surface (). The box () includes a first seal surface (), a female thread () constituted by a single-stage tapered thread, and a box lip () including a second seal surface (). When assembled, the first seal surfaces () are in contact with each other and the second seal surfaces () are in contact with each other. A portion of the male thread () located near the end thereof close to the pin lip () includes a plurality of thread root surfaces extending parallel to the pipe axis (CL) and having the same diameter. A portion of the female thread () located near the end thereof close to the box lip () includes a plurality of thread root surfaces extending parallel to the pipe axis (CL) and having the same diameter.

A threaded joint for steel pipe is provided that ensures good sealing performance and reduces crevice corrosion. A threaded joint includes a pin () and a box (). The pin () includes a first shoulder surface (), a first male thread (), a second shoulder surface (), and a second male thread (). The box () includes a first shoulder surface (), a first female thread (), a second shoulder surface (), and a second female thread (). Supposing that the distance between the shoulder surfaces of the pin () is represented as Land the distance between the shoulder surfaces of the box () is represented as L, and the interference &#x3b4;is defined by Equation (1) given below, then, the threaded joint is constructed such that Equations (2) and (3) given below are satisfied. In Equations (2) and (3), P is the thread pitch of the first male thread (), &#x394;and &#x394;are the lower and upper limits, respectively, for the difference between the numbers of tightening rotations, and &#x3bb; is the elongation of the portion of the pin () located closer to the tip than the second shoulder surface () is.[Formula 1]&#x3b4;&#x2003;&#x2003;(1)+&#x3bb;&#x2264;&#x3b4;+&#x3bb;&#x2003;&#x2003;(2)&#x394;=&#x2212; 9/100, &#x394;= 3/100&#x2003;&#x2003;(3)

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Tokyo, Japan

Sadao Douchi