EP0230320A1
Expired / Lapsed
EP
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Organic coated steel strip having improved bake hardenability and method for making
Assignee: JFE Steel Corp
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Filing: 1987-01-22
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Granted: —
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Expires: 2007-01-22
Abstract
Abstract An organic coated steel strip having improved bake hardenability is provided which comprises an extra low carbon- steel substrate having bake hardenability, a zinc alloy layer deposited on the substrate in a weight of 10 to 40 g/m 2 , a chromate layer formed on the zinc alloy layer in a weight of at least 10 mg/m 2 of metallic chromium, and an organic coating, optionally containing silica, attached to the chromate layer. The coated strip is prepared by depositing a zinc alloy on an extra low carbon steel substrate, subjecting the substrate to a chromate treatment in an aqueous chromate solution containing a chromate compound, a reducing agent, and an acid residue, resin or silica, and applying an organic coating on the chromate layer and baking the coating at a temperature of up to 150°C.
Inventors
- 👤 Shigeru C/O Technical Research Division Kobayashi
- 👤 Shunichi C/O Technical Research Division Tsugawa
- 👤 Taizo C/O Technical Research Division Mouri
- 👤 Toshio C/O Technical Research Division Ichida
- 👤 Takashi C/O Technical Research Division Obara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 13:34
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/73; C23C22/74; C23C22/78; C23C22/05; C23C22/06; C23C22/24; C23C22/26; C23C22/28; C23C28/00
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
84 words
An organic coated steel strip having improved bake hardenability, comprising an extra low carbon steel substrate having bake hardenability, a layer of a zinc base alloy deposited on one surface of said substrate in a weight of 10 to 40 g/m 2 , a chromate layer formed on said zinc base alloy layer in a weight of at least 10 mg/m 2 calculated as metallic chromium, and an organic coating attached to said chromate layer by baking at a temperature of up to 150°C.
Claim 2
Dependent Claim
84 words
An organic coated steel strip having improved bake hardenability, comprising an extra low carbon steel substrate having bake hardenability, a layer of a zinc base alloy deposited on one surface of said substrate in a weight of 10 to 40 g/m 2 , a chromate layer formed on said zinc base alloy layer in a weight of at least 10 mg/m 2 calculated as metallic chromium, and an organic coating attached to said chromate layer by baking at a temperature of up to 150°C.
Claim 3
Dependent Claim
14 words
The organic coated steel strip of claim 1 wherein said organic coating contains silica.
Claim 4
Dependent Claim
19 words
The-organic coated steel strip of claim 1 wherein said organic coating has a thickness of 0.5 to 3 um.
Claim 5
Independent Claim
99 words
A method for making an organic coated steel strip having improved bake hardenability, comprising the steps of: depositing a layer of a zinc base alloy on one surface of an extra low carbon steel substrate having bake hardenability in a weight of 10 to 40 g/m 2 , subjecting said substrate to a chromate treatment to form a chromate layer on the zinc base alloy layer in a weight of at least 10 mg/m 2 calculated as metallic chromium, and applying an organic coating on the chromate layer and baking the coating at a temperature of up to 150°C.
Claim 6
Independent Claim
99 words
A method for making an organic coated steel strip having improved bake hardenability, comprising the steps of: depositing a layer of a zinc base alloy on one surface of an extra low carbon steel substrate having bake hardenability in a weight of 10 to 40 g/m 2 , subjecting said substrate to a chromate treatment to form a chromate layer on the zinc base alloy layer in a weight of at least 10 mg/m 2 calculated as metallic chromium, and applying an organic coating on the chromate layer and baking the coating at a temperature of up to 150°C.
Claim 7
Dependent Claim
33 words
The method of claim 4 wherein said chromate treatment uses an aqueous chromate solution containing a chromate compound, a reducing agent, and at least one member selected from acid residues, resins and silica.
Claim 8
Independent Claim
104 words
A method for making an organic coated steel strip having improved bake hardenability, comprising the steps of: depositing a layer of a zinc base alloy on one surface of an extra low carbon steel substrate having bake hardenability, subjecting said substrate to a chromate treatment to form a chromate layer on the zinc base alloy layer, and applying an organic coating on the chromate layer and baking the coating at a temperature of up to 150°C, wherein said chromate treatment uses an aqueous chromate solution containing a chromate compound, a reducing agent, and at least one member selected from acid residues, resins and silica.
Claim 9
Independent Claim
104 words
A method for making an organic coated steel strip having improved bake hardenability, comprising the steps of: depositing a layer of a zinc base alloy on one surface of an extra low carbon steel substrate having bake hardenability, subjecting said substrate to a chromate treatment to form a chromate layer on the zinc base alloy layer, and applying an organic coating on the chromate layer and baking the coating at a temperature of up to 150°C, wherein said chromate treatment uses an aqueous chromate solution containing a chromate compound, a reducing agent, and at least one member selected from acid residues, resins and silica.
Claim 10
Dependent Claim
25 words
The method of claim 6 wherein said reducing agent is selected from the group consisting of methanol, hydrogen peroxide, ethylene glycol, succinic acid, and succinimide.
Claim 11
Dependent Claim
32 words
The method of claim 7 wherein said reducing agent added is added in a sufficient amount to provide 0.2 to 1.9 gram atoms of hydrogen per gram molecule of Cr0 3 .
Claim 12
Dependent Claim
19 words
The method of claim 6 wherein said acid residue is comprised of the residue of phosphoric or boric acid.
Claim 13
Dependent Claim
30 words
The method of claim 9 wherein said acid residue is added in an amount to give an acid residue to Cr0 3 ratio of from 0.05 to 0.3 by weight.
Claim 14
Dependent Claim
14 words
The method of claim 6 wherein said resin is comprised of an acrylic resin.
Claim 15
Dependent Claim
28 words
The method of claim 11 wherein said resin is added in an amount to give a resin to CrO 3 ratio of from 0.1 to 20 by weight.
Claim 16
Dependent Claim
13 words
The method of claim 6 wherein said silica is comprised of colloidal silica.
Claim 17
Dependent Claim
28 words
The method of claim 13 wherein said silica is added in an amount to give a SiO 2 /CrO 3 ratio of from 0.3 to 3.0 by weight.
References Cited (Backward Citations)
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