US 4,054,173 AGranted

Apparatus for producing completely recrystallized metal sheet

AssigneeHunter Engineering Company

InventorJim Hickam

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Abstract

A method and apparatus for producing extremely fine-grained aluminum sheet in a casting machine having a pair of parallel casting rolls, a pouring tip on the entrance side of the rolls, and means for driving the rolls. Molten aluminum is poured through the tip into the space between the rolls, and the rolls are driven at a speed such that solidification of the metal is completed at a point ahead of the centerline of the rolls, and the frozen metal is then hot-rolled down to the thickness of the roll spacing. During this hot-rolling, the metal is heavily stressed internally by being reduced at least 33% of the thickness at the point of solidification, and this destroys the "as cast" crystal structure and causes complete recrystallization to take place. As compared with conventional roll casters, the present caster has larger-diameter casting rolls, which are driven at a faster speed, and the tip is set back further from the rolls centerline. The resultant cast product is vastly superior to anything produced by prior casters.

Claims1

Dependent claims

In apparatus for continuously casting metal in the form of a sheet or strip having exceedingly fine grain, said apparatus consisting of a pair of parallel casting rolls spaced apart slightly to receive molten metal between them, a pouring tip of heat-insulating material fitted snugly into the converging space between said casting rolls on one side thereof, and means for driving said rolls synchronously in the direction to carry the molten metal from said pouring tip through the space between said rolls, while heat is extracted from the molten metal, causing the same to solidify, the improvement comprising:

said casting rolls having a radius of not less than 18 inches and spaced apart approximately 0.250 inches at their closest point;
the pouring spout being positioned with its outer tip set back from the roll centerline a distance not less than 2.5 inches;
means adapted to drive said rolls at a speed of approximately 0.6 rpm;
and
means adapted to cool said rolls such that the molten metal freezes solidly across the space from one casting roll to the other at a point where the metal is approximately 0.375 inches thick, so that the solidified metal is hot-rolled down to 0.250 inch thickness.

2 more elements

Dependencies are inferred from the claim text.