Claims
- 1. A method of increasing the corrosion resistance of a nickel/iron alloy steel plate for LNG or LPG tanks said plates having a 35-37% nickel content as provided by ASTM SA-658 comprising the steps of:
- (1) coating said steel with metallic nickel in an amount of about 1 to 10 g/m.sup.2 calculated as nickel metal; and
- (2) surface treating said nickel/iron alloy steel plate coated with metallic nickel with a chromating step so as to provide a chromate film on said metallic nickel coating, said chromate film containing 5 to 100 mg/m.sup.2 of chromate calculated as chromium metal.
- 2. The method of claim 1 wherein the nickel coating step of (1) is selected from the group consisting of electroplating and electroless plating.
- 3. The method of claim 2 wherein the nickel coating step is an electroplating step.
- 4. The method of claim 1 wherein the chromating step of (2) comprises treating with chromating solution containing hexavalent chromium, in an amount of about 10 to 200 g/l and trivalent chromium in an amount of 20 to 60% by weight relative to the total chromium content.
Priority Claims (1)
Number |
Date |
Country |
Kind |
56-98216 |
Jun 1981 |
JPX |
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Parent Case Info
This is a divisional of application Ser. No. 652,611 filed Sept. 20, 1984, now U.S. Pat. No. 4,592,965 which is a continuation-in-part of application Ser. No. 392,131 filed June 25, 1982, now abandoned.
US Referenced Citations (10)
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Divisions (1)
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Number |
Date |
Country |
Parent |
652611 |
Sep 1984 |
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Continuation in Parts (1)
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Number |
Date |
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Parent |
392131 |
Jun 1982 |
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