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:
Jul. 23, 2013
Filed:
Aug. 19, 2004
Kazuhiko Honda, Kimitsu, JP;
Koki Tanaka, Futtsu, JP;
Kazuhiko Honda, Kimitsu, JP;
Koki Tanaka, Futtsu, JP;
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Usinor, Puteaux, FR;
Abstract
A process of production for producing a high strength galvannealed steel sheet by a hot-dip galvanized steel sheet production equipment using an all radiant tube type annealing furnace and a production equipment for the same are provided, comprising continuously hot-dip galvanizing a high strength steel sheet having a content of Si of 0.4 to 2.0 wt % during which making the atmosphere of the reducing zone an atmosphere containing Hto 1 to 60 wt % and comprised of the balance of N, HO, O, CO, CO, and unavoidable impurities, controlling the log (PCO/PH) of the carbon dioxide partial pressure and hydrogen partial pressure in the atmosphere to log (PCO/PH)≦−0.5 and the log (PHO/PH) of the water partial pressure and hydrogen partial pressure to log (PHO/PH)≦−0.5, and controlling the log (P/PH) of the total partial pressure Pof the carbon dioxide partial pressure PCOand water partial pressure PHO and the hydrogen partial pressure to −3≦log (P/PH)≦−0.5.