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:
Dec. 18, 2012
Filed:
Mar. 03, 2011
Applicants:
Masaru Izawa, Kobe, JP;
Kunio Goto, Kobe, JP;
Inventors:
Masaru Izawa, Kobe, JP;
Kunio Goto, Kobe, JP;
Assignee:
Sumitomo Metal Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C23C 22/18 (2006.01); C23C 22/12 (2006.01);
U.S. Cl.
CPC ...
Abstract
A chemical conversion treatment liquid which can stably form a phosphate-type chemical conversion film on a steel material for a joint portion of an oil well steel pipe containing 0.5-13% Cr is developed. Using a chemical conversion treatment liquid to which a prescribed amount of potassium is added, a chemical conversion film containing a prescribed amount of potassium compounds and having a prescribed thickness can be formed on the threaded surface of a joint portion of an oil well steel pipe.