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:
Oct. 25, 2005
Filed:
Apr. 22, 2003
Shigeru Nakamura, Wakayama, JP;
Kaori Kawano, Neyagawa, JP;
Tomohiko Omura, Kishiwada, JP;
Toshiharu Abe, Osaka, JP;
Shigeru Nakamura, Wakayama, JP;
Kaori Kawano, Neyagawa, JP;
Tomohiko Omura, Kishiwada, JP;
Toshiharu Abe, Osaka, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A steel material and a steel pipe made by using the same are provided which are to be used in severe oil well environments. Such a highly tough oil well steel pipe can be produced by rolling the base material, quenching the rolling product from the austenite region and tempering the same so that the relationship between the content of Mo [Mo] in the carbides precipitated at austenite grain boundaries and the austenite grain size (according to ASTM E 112) can be defined by the formula (a) given below. In this manner, steel pipes suited for use even under oil well environments becoming more and more severe can be produced while satisfying the requirements that the cost should be rationalized, the productivity improved and energy saved.[Mo]≦exp(5)+5  (a)