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:
Oct. 27, 1998
Filed:
Jan. 17, 1997
Yoshihiro Okamura, Tokai, JP;
Ryota Yamaba, Tokai, JP;
Tomoya Koseki, Chiba, JP;
Ichiro Nakagawa, Kurashiki, JP;
Nippon Steel Corporation, Tokyo, JP;
Kawasaki Steel Corporation, Hyogo, JP;
Abstract
An extra high tensile steel having an excellent stress corrosion cracking resistance in sea water and a yield strength of 1080 MPa or more is provided. A slab comprising, in terms of % by weight, 0.04 to 0.09% of C, 0.01 to 0.10% of Si, 0.05 to 0.65% of Mn, 8.0 to 11.0% of Ni, 0.5 to 1.5% of Mo, 0.2 to 1.5% of Cr, 0.02 to 0.20% of V and 0.01 to 0.08% of Al with the balance consisting of iron and unavoidable impurities is heated to a temperature between 1000.degree. C. and 1250.degree. C., hot rolled at a temperature of Ar' point or above, air-cooled, reheated at a rate of 120.degree. C./min or less to a temperature region of from (A.sub.C3 point--40.degree. C.) to (A.sub.C3 point+40.degree. C.), quenched and subsequently tempered at a temperature of the A.sub.C1 point or below.