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:
May. 11, 2004
Filed:
Dec. 20, 2002
Hiroyasu Fujii, Kitakyushu, JP;
Yoshiyuki Ushigami, Futtsu, JP;
Shuichi Nakamura, Futtsu, JP;
Kenichi Murakami, Kitakyushu, JP;
Norihiro Yamamoto, Kitakyushu, JP;
Kiyoshi Sawano, Futtsu, JP;
Shuichi Yamazaki, Futtsu, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
The present invention provides a method for producing a grain-oriented silicon steel sheet not having inorganic mineral films by using an annealing separator capable of preventing the inorganic mineral films composed of forsterite (Mg SiO ), and so on, from forming during final annealing, comprising the steps of decarburization annealing followed by coating of annealing separator and final annealing, wherein alumina powder calcined at a calcination temperature of 900 to 1,400° C., or further having a BET specific surface area of 1 to 100 m /g, an oil absorption of 1 to 70 ml/100 g, and/or having a gamma ratio of 0.001 to 2.0, is used as the annealing separator. Magnesia having a BET specific surface area of 0.5 to 5 m /g may be added to said alumina powder.