THREADED JOINT FOR STEEL PIPE - NIPPON STEEL & SUMITOMO METAL CORP

Title:

THREADED JOINT FOR STEEL PIPE

Document Type and Number:

WIPO Patent Application WO/2015/105054

Kind Code:

A1

Abstract:

Provided is a threaded joint for a steel pipe in which each of the flank angles (θ) of a load flank surface (15) of a male thread section (11) of a pin (10) and a load flank surface (24) of a female thread section (21) of a box (20) is less than 0°. The female thread section (21) is divided into an incomplete thread section area (21b) and a complete thread section area (21a) in this order from a side that is near a seal surface (26). The thread valley bottom surface (23) of the female thread section (21) is on the same tapered surface across all of both thread section areas (21a, 21b). The incomplete thread section area (21b) has a length that is three times or more the length of the thread pitch and a thread height that is lower than the thread height of the complete thread section area (21a). In a fastened state, each of shoulder surfaces (17, 27) are brought into contact with one another, each of seal surfaces (16, 26) are brought into contact with one another, and a gap is formed between the thread valley bottom surface (13) of the male thread section (11) and the thread peak surface (22) of the female thread section (21) in the incomplete thread section area (21b). As a result, sealing performance with respect to external pressure is maintained, and sealing performance with respect to internal pressure is improved.

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JPH07293758	PIPE JOINT
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Inventors:

INOSE KEITA (JP)
OOTA FUMIO (JP)
UGAI SHIN (JP)
SUGINO MASAAKI (JP)

Application Number:

PCT/JP2015/000076

Publication Date:

July 16, 2015

Filing Date:

January 09, 2015

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)
VALLOUREC OIL & GAS FRANCE (FR)

International Classes:

F16L15/04

Foreign References:

JP2009531603A	2009-09-03
JPH06331070A	1994-11-29
JPH02271191A	1990-11-06
JPH1089554A	1998-04-10
JPH09126366A	1997-05-13
US2062407A	1936-12-01
JPH0280886A	1990-03-20
JPS62196488A	1987-08-29
JPH1089555A	1998-04-10

Other References: