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:
Dec. 09, 1980
Filed:
Feb. 12, 1979
Fusao Koshiga, Kawasaki, JP;
Jinkichi Tanaka, Yokohama, JP;
Itaru Watanabe, Yokohama, JP;
Motoaki Suzuki, Yokohama, JP;
Toshifumi Kojima, Yokohama, JP;
Hiroyoshi Matsubara, Fukuyama, JP;
Tatsumi Osuka, Fukuyama, JP;
Kenji Takeshige, Fukuyama, JP;
Takashi Nagamine, Fukuyama, JP;
Osamu Hirano, Fukuyama, JP;
Nippon Kokan Kabushiki Kaisha, Tokyo, JP;
Abstract
In longitudinally seam-welding a pipe-blank for welded steel pipe from the inside along a groove by the GMA welding process which comprises using direct electric current supplied to a plurality of consumable electrodes in tandem through at least one cable as the welding current, at least two even-numbered consumable electrodes are used, half of said consumable electrodes being connected to said direct current so as to be positive in polarity and the remaining half of said consumable electrodes being connected to said direct current so as to be negative in polarity, to enable lines of magnetic force produced by said direct electric current for welding flowing through said at least one cable introduced into said pipe-blank to cancel each other, thereby preventing magnetization of said pipe-blank and the resulting magnetic arc blow of the welding arc.