Process for preparing the metal surface of an article, especially one made of steel sheet, for direct-on enameling

• US 5,766,374 A
• Filed: 09/24/1996
• Issued: 06/16/1998
• Est. Priority Date: 09/28/1995
• Status: Expired due to Fees

• Current Assignee: Sollac, Co.
• Original Assignee: Sollac, Co.
• Inventors: Vonner, Daniel, Guillot, Louis, Cholet, Vincent
• Primary Examiner(s): Silverberg, Sam
• Application Number:
  US08/710,957
• Time in Patent Office: 630 Days
• Field of Search: 148/256, 148/254, 205/183
• US Class Current: 148/254
• CPC Class Codes: C23C 22/36 containing also phosphates
• CPC Class Codes: C23C 22/42 containing also phosphates
• CPC Class Codes: C23D 3/00 Chemical treatment of the metal surfaces prior to coating

Abstract

Process in which the said surface is pickled and then treated in two steps, a first treatment step of so-called "amorphous" phosphatization, suitable for depositing a coat of at least 0.2 g/m², followed by a second treatment step called "nickel plating".

In this way, it is possible to limit the amount of sludge at pickling while at the same time obtaining good adhesion of the enamel.

In a complete sequence for manufacturing an article formed from direct-on enameled metal sheet, the sheet may be formed after pickling, especially after the first step called phosphatization and before the second step called nickel plating.

Claims

1. A process for manufacturing an article made of direct-on enameled steel sheet, which process comprises a forming operation, a surface preparation operation in which a steel sheet surface is pickled under conditions which remove at most 15 gms of steel per square meter of sheet surface and then subjected to amorphous phosphatization with a phosphatization solution comprising less than 0.05 g/l of Ni and Mo under conditions which form a coat of at least 0.2 g/m² on the surface of said sheet followed by nickel plating, and an enameling operation, wherein in said process the forming operation is carried out after pickeling and after amorphous phosphatization.

2. The process as claimed in claim 1, wherein said nickel plating is conducted under conditions which deposit between 0.5 and 2.5 g/m² on the surface of said metal sheet.

3. The process as claimed in claim 1, wherein said nickel plating is carried out after the forming operation.

4. In a process for preparing the surface of a steel sheet for direct-on enameling, the improvement comprising:

pickeling the surface of said steel sheet under conditions which remove at most 15 gms of steel per square meter of said sheet surface;

subjecting said sheet to amorphous phosphatization with a phosphatization solution comprising less than 0.05 g/l of Ni and Mo so as to form a coat of at least 0.2 g/m² on a surface of said sheet; and

nickel plating said pickeled and phosphatized metal surface.

5. The process as claimed in claim 4, wherein nickel plating is conducted so as to deposit between 0.5 and 2.5 g/m² on the surface of said pickeled and phosphatized sheet.