(19)
(11) EP 0 545 908 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
12.01.1994 Bulletin 1994/02

(43) Date of publication A2:
09.06.1993 Bulletin 1993/23

(21) Application number: 93102764.3

(22) Date of filing: 07.05.1990
(51) International Patent Classification (IPC)5: C25D 5/36, C25F 1/06
(84) Designated Contracting States:
BE DE FR GB

(30) Priority: 08.05.1989 JP 114791/89
21.11.1989 JP 302562/89

(62) Application number of the earlier application in accordance with Art. 76 EPC:
90401217.6 / 0397555

(71) Applicant: SUMITOMO METAL INDUSTRIES, LTD.
Osaka-shi, Osaka-fu 540 (JP)

(72) Inventors:
  • Oshima, Kazuhide
    Wakayama-shi, Wakayama-ken (JP)
  • Morino, Hisakazu
    Wakayama-shi, Wakayama-ken (JP)
  • Kondo, Tomio
    Wakayama-shi, Wakayama-ken (JP)
  • Shimada, Yasuo
    Sennan-shi, Osaka (JP)
  • Nonaka, Tadashi
    Wakayama-shi, Wakayama-ken (JP)
  • Oishi, Hiroshi
    Wakayama-shi, Wakayama-ken (JP)
  • Yamanaka, Yoshikazu
    Wakayama-shi, Wakayama-ken (JP)
  • Hoboh, Yoshihiko
    Sennan-gun, Osaka (JP)
  • Yakawa, Atsuhisa
    Nishinomiya-shi, Hyogo-ken (JP)

(74) Representative: Schrimpf, Robert et al
Cabinet Regimbeau 26, Avenue Kléber
F-75116 Paris
F-75116 Paris (FR)


(56) References cited: : 
   
     
    Remarks:
    This application was filed on 22 - 02 - 1993 as a divisional application to the application mentioned under INID code 60.
     


    (54) Electroplating of hot-galvanized steel sheet and continuous plating line therefor


    (57) A continuous multi-layer plating line for steel sheet which includes a hot-galvanizing apparatus to form a galvanized coating and optionally to alloy the coating and an electroplating apparatus to form an electroplated coating on the galvanized coating. Between the hot-galvanizing apparatus and the electroplating apparatus, a post-galvanizing surface treatment apparatus effective for removing surface oxide contaminants and activating the surface of the galvanized coating is disposed and the galvanized steel sheet is treated thereby prior to electroplating. The post-galvanizing surface treatment is carried out by applying an alkali solution having a pH of at least 12 to the surface of the galvanized coating, by alkali electrolysis, by cathodic electrolysis, by cooling the galvanized steel sheet with the said alkali solution, or by skin-pass rolling using the said alkali solution as a skin-pass roling liquid.





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