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:
Jun. 23, 2015
Filed:
Feb. 22, 2012
Masahide Takagi, Tokyo, JP;
Shinji Taenaka, Tokyo, JP;
Tetsu Satoh, Tokyo, JP;
Yuki Motegi, Tokyo, JP;
Takashi Oosawa, Tokyo, JP;
Masahide Takagi, Tokyo, JP;
Shinji Taenaka, Tokyo, JP;
Tetsu Satoh, Tokyo, JP;
Yuki Motegi, Tokyo, JP;
Takashi Oosawa, Tokyo, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
This depression-provided steel pipe has plural depressions on an outer peripheral surface, the depressions being formed so as to form a line along an axial direction of the steel pipe, in which each of the depressed portions has, inside thereof, a columnar groove portion extending along the axial direction of the steel pipe and depressed deeper than a bottom surface of these depressed portions; 0.95≦H/H≦1.05 is satisfied, where His an average Vickers hardness in each of the depressed portions, and His a Vickers hardness at a portion between the depressed portions adjacent to each other in the axial direction of the steel pipe; and the outer peripheral surface is covered with a mill scale.