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:
Apr. 24, 2001
Filed:
Sep. 21, 1998
Applicant:
Inventors:
Shiro Torizuka, Ibaraki, JP;
Kaneaki Tsuzaki, Ibaraki, JP;
Kotobu Nagai, Ibaraki, JP;
Osamu Umezawa, Ibaraki, JP;
Assignee:
National Research Institute for Metals, Ibaraki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 3/800 ; C22C 3/804 ; C22C 3/802 ; C21D 8/00 ;
U.S. Cl.
CPC ...
C22C 3/800 ; C22C 3/804 ; C22C 3/802 ; C21D 8/00 ;
Abstract
The invention provides an ultra-fine grain steel comprising fine ferrite grains as oriented at random and surrounded by large angle grain boundaries. The steel comprises fine ferrite grains having a mean grain size of not larger and 3.0 &mgr;m and surrounded by large angle grain boundaries having an misorientation not smaller than 15°.