Hydril Company

Patrick E McDonald

Keith C Mott

Charles A Bollfrass

Gary E Kirsch

H Paul Barringer

Leonard S Landriault

A tubular connection includes a shallowly tapered conical sealing surface. The areas on the pin member where make up and sealing respectively occur in the various embodiments comprise multiple angles and surface texturing for the purpose of lubricant retention, facilitate burnishing and reduce the propensity for galling in multiple make up and break out situations. The pin taper in each case is slightly less than the box taper. The area on the pin member is textured ahead of the very smooth seal area to retain some thread compound even after repeated makeups of the connection. The area ahead of the sealing area where stabbing contact is made is textured in the 125-250 R.sub.a range while the smooth seal area is textured about 63 R.sub.a to provide a gas tight seal under high pressure and severe conditions of combined loads and thermal shock. Hence, the invention allows the use of a smoother seal surface for high temperature gas tight integrity than would otherwise be achieved after the connection is subjected to repeated make ups and break outs.

Tubular pin configuration to prevent galling while ensuring sealing

A pipe joint of the free-running thread type is provided with engaging shoulders on the pin and box that are positioned for the metal adjacent the shoulders to be stressed by make-up torque beyond its yield joint and extruded laterally of the shoulders into grooves to mechanically lock the joint in its made-up position.

Pipe joint

A new and improved threaded connector having one or more non-tapered threads on separate diametral steps with at least one flank 'hooked' so as to achieve a tensile strength approximately that of the tubular body, is disclosed. The wall thickness of the female member is controlled to improve thread loading and enable inwardly radial movement with the male member to prevent 'pulling out' under axial tensile loading. The outer thread step on the male member may only partially engage the threads on the female member such that the critical reduction of the tube wall thickness at the thread roots is a minimum. The resulting threaded connection formed on tubular members has a tensile efficiency in excess of the tube body yield strength and approaching that of the tube body ultimate tensile strength.

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Houston, TX, United States of America

Patrick E McDonald