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:
Nov. 10, 2009
Filed:
Apr. 23, 2008
Koichi Sakamoto, Kobe, JP;
Tomoko Sugimura, Kobe, JP;
Atsuhiko Yoshida, Kobe, JP;
Yoshio Fukuzaki, Kobe, JP;
Sumie Suda, Kobe, JP;
Koichi Sakamoto, Kobe, JP;
Tomoko Sugimura, Kobe, JP;
Atsuhiko Yoshida, Kobe, JP;
Yoshio Fukuzaki, Kobe, JP;
Sumie Suda, Kobe, JP;
Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.), Kobe-shi, JP;
Abstract
The present invention relates to a high-cleanliness steel having a high fatigue strength and high cold workability, and a method of making the high-cleanliness steel. The method adds a Li—Si alloy having a Li content between 20 and 40% and/or LiCOas a Li-containing substance to a molten steel. The Li-containing substance is added to the molten steel after the completion of a series of steps of a ladle refining process including composition adjustment, temperature adjustment and slag refining. The high-cleanliness steel has a total-Li content between 0.020 and 20 ppm by mass and contains 1.0 or below oxide inclusion particle having a major diameter of 20 μm or above at a maximum in 50 g of the steel wire. The steel contains an oxide inclusion that has a CaO content between 15 and 55%, SiOcontent between 20 and 70%, an AlOcontent of 35% or below, a MgO content of 20% or below and a LiO content between 0.5 and 20%. The high-cleanliness steel has improved fatigue characteristics and improved cold workability.