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:
Sep. 21, 2004
Filed:
Aug. 16, 2003
Shinichi Fukunaga, Kitakyushu, JP;
Ryoji Nishihara, Kitakyushu, JP;
Kazuhisa Tanaka, Kitakyushu, JP;
Mitsuji Asano, Kitakyushu, JP;
Kazunori Yasumitsu, Kitakyushu, JP;
Yuji Hiramoto, Kitakyushu, JP;
Hiroyuki Mitake, Futtsu, JP;
Takeshi Kawachi, Futtsu, JP;
Nippon Steel Corporation, Tokyo, JP;
Abstract
A plasma torch used for heating a molten steel has an outer cylinder is provided. The torch includes a double tube, the bottom of which is blocked annularly. The torch also includes a bottomed cylindrical anode electrode that is installed within the outer cylinder with a gap existing between the anode electrode and the inside of the double tube. The plasma torch is provided such that pure copper is not used as a material for the anode electrode, the material has a softening point exceeding 150° C., and the ratio of an electric conductivity D of the anode electrode to an electric conductivity N of the outer cylinder satisfies the formula: 0.2≦D/N<1.0. The plasma torch prevents the melting loss and wear of the anode electrode caused by the splashes and the heat produced in the anode electrode, suppresses generation of a side arc, shows an extended life, and stabilizes the casting operation and improves the quality of the slab.