National Steel Corporation

Gordon L Peters

John R Smith

William T Saunders

Tinplate container stock coated with a substantially uniform film of lubricant, the lubricant film consisting essentially of a citric acid ester lubricant in an amount of at least 1.8 grams per basebox, and a method for its use in drawing and ironing operations.

Lubricated tinplate for drawing and ironing operation

In the production of a seam-free can body from a sheet of flow brightened electrolytic tinplate by a method involving cold forming which includes a drawing step alone or a drawing step plus a redrawing step or plus a wall ironing step to produce a cold formed cup having inherently poor corrosion resistance, the improvement which comprises heat treating the cold formed cup at a temperature ranging from about 400.degree. to about 448.degree. F. for a period of time between about 10 minutes at the lower end of the temperature range and about 10 seconds at the upper end of the temperature range.

Production of corrosion resistant seam-free can bodies from tinplate

The invention provides a novel method of increasing the corrosion resistance and improving the organic coating characteristics of cold rolled flat steel. In practicing the method, cold rolled flat steel in the as rolled condition having iron oxide and thermally degradable rolling oil on the surface thereof is heat treated at a tempterature sufficiently elevated to thermally degrade the rolling oil. The surface of the cold rolled steel has a relatively low corrosion resistance and relatively poor organic coating characteristics initially, and the heat treatment is continued until the corrosion resistance and the organic coating characteristics of the resulting heat treated steel are improved. Thereafter the heat treated steel is cooled to a temperature sufficiently low to prevent further thermal degradation of the rolling oil and produce a residual film on the heat treated steel surface which imparts corrosion resistance and improved organic coating characteristics. In a further variant of the invention, as rolled cold rolled flat steel of container stock gage is heat treated as described above, a hardenable fluid organic protective coating composition is applied to the resulting cooled heat treated steel, and thereafter the coating composition is hardened to produce container stock having a hardened coating of an organic protective coating thereon. The invention further provides the various products produced by the method of the invention.

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Weirton, WV, United States of America

Gordon L Peters