Method for making lithoplate
AssigneeAluminum Company of America
InventorsElwin L. Rooy, Gerald R. Petrey, James R. Weaver, Douglas A. Granger, Raymond T. Richter, H. Gray Reavis, Jr.
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Abstract
An improved method of making a lithoplate from a 5XXX type alloy which includes controlling the composition and casting practices to eliminate forming a pine tree metal structure in an ingot used for rolling a workpiece to be made into lithoplate. The method also includes homogenizing and hot rolling the ingot at a controlled initial temperature to produce a desired grain and metal microstructure in the sheet rolled from the ingot which is suited for providing a surface having substantially uniform and evenly distributed craters produced by an electrochemical method of graining.
Claims9
A method for producing lithoplate, comprising:
- providing a molten aluminum alloy consisting essentially of the following elements in percent by weight:
- Cu-0 to 0.20%;
- Si - 0.055 to 0.085%;
- Fe - 0.55 to 0.75%;
- Mn - 0 to 0.20%;
- Mg - 0.40 to 0.70%;
- Zn - 0 to 0.25%;
- Cr - 0 to 0.10%;
- Ti - 0 to 0.05% (when cast);
- V - 0 to 0.025%;
- other elements - 0 to 0.05%, not to exceed 0.15% total;
- and the remainder Al;
- casting the alloy into a mold to form an ingot;
- homogenizing the ingot at a suitable temperature for a period of time suitable to ensure homogenization of the ingot;
- hot rolling the ingot to produce a reroll stock;
- cold rolling the reroll stock to a finished gauge workpiece;
- and
- graining at least one surface of the workpiece.
A lithoplate having a grained surface, formed of a homogenized aluminum alloy of the 5XXX series, the lithoplate being anodized and substantially free of surface streaks.
A lithoplate having a grained surface coated with a light-sensitive resist, the improvement comprising the lithoplate having a composition consisting essentially of 0.20% max. Cu, 0.055-0.085% Si, 0.55-0.75% Fe, 0.20% max. Mn, 0.40-0.70% Mg, 0.25% max. Zn, 0.10% max. Cr, 0.05% max. Ti, 0.025% max. V, 0.05% max. each of other elements not to exceed 0.15% total, and the remainder Al.
Dependencies are inferred from the claim text.