Armco Steel Company, L.p.

Cynthia A Gosselin

Frederick Alan Myers

Douglas J Robbins

A bake hardenable steel sheet ready for deep drawing is coated on at least one side with a continuous chromium bearing epoxy coating. The sheet is roll coated with continuous liquid film containing at least 2 wt. % of a water dispersible or emulsifiable epoxy resin or a mixture of resins containing the epoxy resin, at least 0.5 wt. % of a chromium compound and 25-97 wt. % of water. The liquid coated sheet is induction heated at a temperature of 149-227.degree. C. for sufficient time to form a coating resistant to dissolution of chromium and a steel base metal having a yield point elongation no greater than 0.3% and retaining good bake hardenability characteristics. The chromium bearing epoxy coating is impervious to moisture, can readily be welded and possesses sufficient toughness and lubricity to allow deformation of the sheet without additional external lubricant. A deeply drawn article formed from the sheet has enhanced painting characteristics.

Method for coating bake hardenable steel with a water based chromium

Zinc or zinc alloy plated steel sheet ready for deep drawing coated with 1-5 gm/m.sup.2 of a dry, tack free continuous thermoplastic acrylic coating. The coating is formed by inductively heating the sheet to a temperature of about 149.degree.-246.degree. C. for no more than 10 seconds after being roll coated with a continuous liquid film of an aqueous solution including an acrylic polymer. The acrylic coating forms a protective film that is impervious to moisture, oil, and dirt, is able to be welded and adhesively bonded and possesses sufficient toughness and lubricity to allow deformation of the sheet without additional external lubricant. A deep drawn article formed from the sheet has enhanced painting characteristics after the acrylic coating is removed and the article is coated with a phosphate coating.

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Middletown, OH, United States of America

Cynthia A Gosselin