Process for phosphating steel strip galvanized on one side
AssigneesHenkel Kommanditgesellschaft auf Aktien, Krupp Hoesch Stahl AG
InventorsJoerg Riesop, Raschad Mady, Dieter Geruhn, Frank Panter, Franz Ricke, Hubertus Peters, Juergen Verheien, Manfred Wessel
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Abstract
A process for phosphating a galvanized surface of a steel strip electrolytically galvanized on one side by contacting the galvanized surface of the steel strip with a phosphating solution containing 1.0 to 6 g/l zinc, 0.5 to 5.0 g/l nickel and 14 to 25 g/l phosphate at a temperature of 40.degree. to 70.degree. C. for from 2 to 20 seconds. The ungalvanized surface remains metal bright.
Claims33
A process for phosphating a galvanized surface of a steel strip electrolytically galvanized on one side to form a nickel-containing phosphate coating which comprises:
- contacting at least the galvanized side of the steel strip for from 2 to 20 seconds at a temperature of 40.degree. C. to 70.degree. C. with a phosphating solution, comprising
- a) Zn.sup.2+ cations:
- 1.0 to 6.0 g/l,
- b) Ni.sup.2+ cations:
- 0.5 to 5.0 g/l,
- c) PO.sub.4.sup.3- anions:
- 14 to 25 g/l,
- "free acid" content:
- 3.5 to 8.0 points,
- "total acid" content:
- 22 to 40 points.
- to form a nickel containing phosphate coating of from 0.5 to 2 gm.sup.-2 whereby an ungalvanized surface of the steel strip remains metal bright.
Dependencies are inferred from the claim text.