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:
Jun. 18, 2002
Filed:
Oct. 11, 2000
Masayuki Hashimura, Muroran, JP;
Hiroshi Hagiwara, Muroran, JP;
Takanari Miyaki, Muroran, JP;
Toshio Banno, Muroran, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention provides a spring steel showing a sufficient reduction in area and an impact toughness while the steel has a high strength, in particular a tensile strength as high as at least 1,500 Mpa. A high toughness spring steel according to the present invention comprises, based on mass, 0.45 to 0.85% of C, 0.9 to 2.5% of Si, 0.1 to 1.2% of Mn, 0.1 to 2.0% of Cr, 0.005 to 0.07% of Ti, 0.001 to 0.007% of N, the Ti content being greater than four times the N content in terms of percent by mass, 0.0005 to 0.0060% B, at least one of 0.0005 to 0.01% Mg, 0.0005 to 0.01% La, and 0.0005 to 0.01% Ce, P and S with restrictive contents of less than 0.020% and less than 0.020%, respectively, and the balance of Fe and unavoidable impurities, and selectively contains V, Nb, Ni, Mo and Cu. The percent area of oxides and sulfides is not more than 0.1%.