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:
Dec. 07, 2004
Filed:
Jul. 02, 2002
Masami Taguchi, Ube, JP;
Ryo Ishibashi, Hitachi, JP;
Yasuhisa Aono, Hitachi, JP;
Hidehiko Sumitomo, Ube, JP;
Hiroki Masumoto, Fukuoka, JP;
Masakuni Fujikura, Nagoya, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A high-strength and high-toughness ferritic steel having a tensile strength of not less than 1,000 MPA and a Charpy impact value of not less than 1 MJ/m is provided. A ferritic steel comprising, by weight, not more than 1% Si, not more than 1.25% Mn, 8 to 30% Cr, not more than 0.2% C, not more than 0.2% N, not more than 0.4% O, a total amount of not more than 12% of at least one compound-forming element selected from the group of Ti, Zr, Hf, V and Nb in amounts of not more than 3% Ti, not more than 6% Zr, not more than 10% Hf, not more than 1.0% V and not more than 2.0% Nb, also containing where necessary not more than 0.3% Mo, not more than 4% W and not more than 1.6% Ni, and the balance consisting of Fe and unavoidable impurities, and having an average crystal grain size of not more than 1 &mgr;m, can be obtained by a method comprising encapsulating a steel powder produced by mechanical alloying, and subjecting the encapsulated steel powder to plastic deformation.