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:
May. 27, 2008
Filed:
Jun. 24, 2005
Applicant:
Hiroshi Matsuo, Nishinomiya, JP;
Inventor:
Hiroshi Matsuo, Nishinomiya, JP;
Assignee:
Sumitomo Metal Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 38/18 (2006.01); C22C 38/40 (2006.01);
U.S. Cl.
CPC ...
Abstract
A steel tube excellent in exfoliation resistance of scale on its inner surface is provided. The steel tube includes 9 to 28% by mass of Cr and has a maximum height of profile (Rz) on the inner surface after cold working of 15 μm or more. Preferably ΔHv of the tube is 100 or more, wherein ΔHv is the difference in Vickers hardness between an inner surface layer and a thickness center part of the tube. The steel may desirably have a microstructure of ASTM austenite grain size No.. or more.