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:
Feb. 19, 2002
Filed:
Mar. 02, 1999
Applicant:
Inventors:
Assignee:
National Research Institute for Metals, Ibaraki, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C22C 3/804 ;
U.S. Cl.
CPC ...
C22C 3/804 ;
Abstract
Ups and downs having a cycle of not more than 5 &mgr;m and an amplitude of not less than 200 nm are formed in a part of not less than 70% per unit length of a prior-austenite grain boundary which is observed in a linear form when seen from a vertical plane by a series of steps of subjecting a steel in a state of austenite to a deformation in not less than 30% of a total area reduction rate at a temperature region which is lower than recrystallization temperature of austenite, and subsequently cooling a deformed steel without causing neither recrystallization nor phase transformation of a diffusion type.