Composition for controlling spangle size, a coated steel product, and a coating method
AssigneeBethlehem Steel Corporation
InventorErin T. McDevitt
Life of this patent
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Abstract
A method of coating of steel products such as plate and sheet using an aluminum-zinc coating alloy includes modifying the coating bath with a particulate compound constituent in effective amounts to control the spangle facet size of the coated product, improve tension bend rust stain performance, improve coated surface appearance when brushed, and coated product paintability. Constituents include borides such as titanium boride and aluminum borides, carbides such as titanium carbide, and aluminides such as titanium aluminide. The method produces a coated steel product that does not require temper rolling for painting.
Claims19
In a method of coating a steel product using a molten aluminum-zinc alloy bath, the improvement comprising modifying the composition of the aluminum-zinc alloy by adding an effective amount of one or more of a particulate compound constituent that produces a coated spangle size on a substrate of between about 400 to 500 microns, said grain refining particulate compound selected from the group consisting of boride compounds in an amount between about 0.0008 to 0.0012% by weight, and having one of titanium and aluminum.
In a coated steel article comprising a steel substrate;
- and an aluminum-zinc coating thereon, the improvement comprising the aluminum-zinc coating being modified with an effective amount of one or more of a particulate compound constituent selected from the group consisting of boride compounds having one of titanium and aluminum, so that said aluminum-zinc coating has a spangle size of between about 400 to 500 microns.
In an aluminum-zinc steel product coating composition capable of producing a coated steel substrate with a coating spangle size between about 400 to 500 microns, the improvement comprising an aluminum-zinc alloy including an effective amount of one or more of a particulate compound constituent selected from the group consisting of boride compounds in an amount between about 0.0008-0.0012% by weight, and having one of titanium and aluminum.
Dependencies are inferred from the claim text.