The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 22, 2008
Filed:
Jan. 29, 2004
Keishi Matsumoto, Takarazuka, JP;
Kunio Goto, Kobe, JP;
Toshiro Anraku, Nishinomiya, JP;
Shigeo Nagasaku, Nishinomiya, JP;
Hideo Yamamoto, Takarazuka, JP;
Keishi Matsumoto, Takarazuka, JP;
Kunio Goto, Kobe, JP;
Toshiro Anraku, Nishinomiya, JP;
Shigeo Nagasaku, Nishinomiya, JP;
Hideo Yamamoto, Takarazuka, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Vallourec Mannesmann Oil & Gas France, Aulnoye-Aymeries, FR;
Abstract
A threaded joint for steel pipes comprising a pinand a boxeach having a contact surface comprising a threaded portionorand an unthreaded metal contact portionis provided with improved anti-galling propertied by forming a lubricating coating on the contact surface of at least one of the pin and the box, the lubricating coating exhibiting a self-repairing function by liquid lubrication and having a decreased greasiness. The lubricating coating is (1) a coating which comprises a lower lubricant layer which is in liquid form in the temperature range of above 0° C. and below 40° C. and an upper lubricant layer which is in solid form at 40° C., or (2) a coating which is semi-solid or solid at 40° C. and is formed of a mixture comprising a lubricating oil which is in liquid form in the temperature range of above 0° C. and below 40° C. and a wax which is in solid form at 40° C., the mixture preferably having been heated so as to liquefy the wax and dissolve in each other the wax and lubricant oil.