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.

Date of Patent:
Dec. 17, 2013

Filed:

Oct. 07, 2009
Applicants:

Yasuhide Ishiguro, Chiyoda-ku, JP;

Akio Sato, Chiyoda-Ku, JP;

Yasuhisa Shimizu, Wako, JP;

Inventors:

Yasuhide Ishiguro, Chiyoda-ku, JP;

Akio Sato, Chiyoda-Ku, JP;

Yasuhisa Shimizu, Wako, JP;

Assignees:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D 8/10 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); F16L 9/00 (2006.01); B21C 37/06 (2006.01);
U.S. Cl.
CPC ...
Abstract

There is provided a high-strength steel tube having excellent chemical conversion treatability and excellent formability and a method for manufacturing the high-strength steel tube. More specifically, in processing a mother steel sheet containing, on the basis of mass percent, 0.05% or more C, more than 0.7% Si, and 0.8% or more Mn into a pipe shape, the sum total of absolute circumferential surface strains each applied in individual process steps of the processing is 5% or more as nominal strain. A welded steel tube thus manufactured using a steel sheet even containing more than 0.7% Si can have excellent chemical conversion treatability without mechanical grinding or chemical pickling treatment.


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