Aluminum coated steel sheet and process for producing the same
First Claim
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1. An aluminum hot dip coated steel sheet consisting essentially of(1) a steel substrate containing 0.002 to 0.02% by weight of solute N and not more than √
- 5/3N-1/300% by weight of total C, wherein N represents the percentage of the solute N, and having a recrystallized structure;
(2) an aluminum coating layer on at least one surface of said steel substrate comprising essentially Al and 1 to 15% by weight of spheroidal Si and having a recrystallized structure, and;
(3) a discontinuous intermediate layer at the interface between said steel substrate and aluminum coating layer and comprising essentially Al--Fe--Si intermetallic compounds.
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Abstract
An aluminum coated steel sheet having excellent formability and corrosion resistance comprising a steel substrate of a recrystallized structure, an Al--Si coating layer of a recrystallized structure on at least one surface of the substrate, and a discontinuous intermediate layer of Al--Fe--Si intermetallic compounds. The product may be conveniently produced by rolling an Al--Si hot dipped steel sheet and annealing the rolled sheet under suitably selected conditions.
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Citations
5 Claims
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1. An aluminum hot dip coated steel sheet consisting essentially of
(1) a steel substrate containing 0.002 to 0.02% by weight of solute N and not more than √ - 5/3N-1/300% by weight of total C, wherein N represents the percentage of the solute N, and having a recrystallized structure;
(2) an aluminum coating layer on at least one surface of said steel substrate comprising essentially Al and 1 to 15% by weight of spheroidal Si and having a recrystallized structure, and; (3) a discontinuous intermediate layer at the interface between said steel substrate and aluminum coating layer and comprising essentially Al--Fe--Si intermetallic compounds. - View Dependent Claims (2)
- 5/3N-1/300% by weight of total C, wherein N represents the percentage of the solute N, and having a recrystallized structure;
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3. A process for the production of an aluminum coated steel sheet comprising the steps of
(a) rolling an aluminum hot dip coated steel sheet, which comprises a steel substrate containing 0.002 to 0.02% by weight of solute N and not more than √ - 5/3N-1/300% by weight of total C, wherein N represents the percentage by weight of the solute N;
an aluminum coating layer on at least one surface of said steel substrate comprising essentially Al and 1 to 15% by weight of Si, and;
a continuous intermediate layer between said steel substrate and aluminum coating layer and comprising essentially Al--Fe--Si intermediate compounds, at a rolling rate sufficient to cause division of said continuous intermediate layer into sections, and(b) annealing the rolled aluminum coated steel sheet at a temperature sufficient for the recrystallization of said steel substrate but insufficient for Al--Fe mutual diffusion between said steel substrate and aluminum coating layer. - View Dependent Claims (4, 5)
- 5/3N-1/300% by weight of total C, wherein N represents the percentage by weight of the solute N;
Specification