THREADED JOINT FOR STEEL PIPE AND METHOD FOR SURFACE TREATMENT OF THE THREADED JOINT

Title:

THREADED JOINT FOR STEEL PIPE AND METHOD FOR SURFACE TREATMENT OF THE THREADED JOINT

Document Type and Number:

WIPO Patent Application WO/2002/084163

Kind Code:

A1

Abstract:

A threaded joint for steel pipe formed of a pin and a box having a contact surface including threaded parts and a non-threaded metal contact part and capable of preventing a seizure by repeated tightening and loosening operations without applying compound grease thereto, wherein a solid lubricating film including lubricating powder such as molybdenum disulfide and resin binder is formed on the contact surface of at least one of the pin and box by drying the film by a primary heating in the temperature range of 70 to 150 °C and by a secondary heating in the temperature range of more than 150 to 380 °C, the solid lubricating film thus obtained has a Rockwell M scale hardness of 70 to 140, an adhesive strength of 500 N/m or higher obtained by the SAICAS method (surface-boundary cutting method), and excellent seizure resistance and airtightness even in a high temperature well environment, and, when ultraviolet ray shielding particles such as titanium oxide are contained in the solid lubricating film, the rust-proofness of the threaded joint is increased.

Inventors:

GOTO KUNIO (JP)

Application Number:

PCT/JP2002/003588

Publication Date:

October 24, 2002

Filing Date:

April 11, 2002

Export Citation:

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Assignee:

SUMITOMO METAL IND (JP)
GOTO KUNIO (JP)

International Classes:

E21B17/042; F16L15/00; F16L15/04; (IPC1-7): F16L15/00

Domestic Patent References:

WO1996010710A1

1996-04-11

Foreign References:

JPH0623459A	1994-02-01
JPH07217777A	1995-08-15
JP2001099364A	2001-04-10

Other References: