Composite-coated flat-rolled sheet metal product
AssigneeWeirton Steel Corporation
InventorWilliam T. Saunders
Life of this patent
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Abstract
Composite-coated flat-rolled steel, product, method of manufacture and method of fabrication in which single or double-reduced low-carbon steel, after surface preparation, is flash-coated with tin (about 0.05 #/bb) which is alloyed with the base metal. Dichromate treatment passivates the tin-iron alloy surfaces depositing a chrome oxide layer prior to application of an organic coating (about 3 to 15 mg/in.sup.2 to each surface). Enhanced coating adhesion of the organic coating enables draw-processing of the double-reduced steel base metal substrate into unitary can bodies without damage to coating or substrate.
Claims1
A one-piece draw-processed can body which is symmetrically disposed in relation to a centrally located axis and having
- a closed endwall,
- a unitary side wall joined to such closed endwall by a
- transition zone which is curvilinear in a cross-sectional plane which includes such centrally located axis, and
- flange metal, formed during such draw processing, located at such open end of the can body defined by such side wall,
- such flange metal being oriented in a plane which is substantially perpendicularly transverse to such centrally located axis;
- with
- such can body being fabricated from composite-coated flat-rolled steel substrate capable of being fabricated directly into sheet metal articles, without damage to such coating or substrate, manufactured by
- selecting base metal from the group consisting of double-reduced flat-rolled steel in the range of about 55 to 90 #/bb and single-reduced flat-rolled steel in the range of about 55 to 110 #/bb.
- preparing both surfaces of such base metal for plating,
- applying about 0.05 #/bb of tin to such base metal,
- alloying such tin with such base metal to present external tin-iron alloy surfaces,
- chemically treating such tin-iron alloy surfaces to passivate such tin-iron alloy and enhance adhesion properties for organic coating so as to enable fabrication of such articles without damage to organic coating or base metal,
- applying organic to each such chemically treated surface to provide an organic coating weight in the range of about 3 to about 15 milligrams/in.sup.2 on each surface, and
- treating such coated substrate to carry out a step selected from the group consisting of curing such organic coating and drying an adhesive for such organic coating.
Dependencies are inferred from the claim text.