Isothermal sheet rolling mill
OwnerArthur G. Metcalfeinventor
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Abstract
A method and apparatus for the solid-state forming of a metallic feedstock into thin sheet or foil is disclosed that uses improved isothermal roll forging techniques. The improvements include the use of rotatable backup rolls for increasing hollow work roll stiffness, two independent work roll heating controllers, a reduced work roll diameter and other means for precise control of conditions within a feedstock "travelling hot zone" (THZ). The disclosed improvements allow the application of isothermal roll forging techniques to the rolling of thin sheets from difficult-to-work, high-strength metals such as aluminides, intermetallics, superalloys, titanium alloys, ODS composites, beryllium, and others in sheets having widths of 24-inches and more.
Claims12
Apparatus for the solid-state forming of a metallic feedstock into a component of selected configuration, comprising:
- a first rotatable electrode means for supporting said feedstock;
- a second rotatable electrode means for applying pressure to said feedstock;
- biasing means for forcing said second electrode means against said first electrode means to exert a pressure of selected magnitude on said feedstock comprising
- at least one first rotatable backup means for supporting said first electrode means and
- at least one second rotatable backup means for applying force to said second electrode means;
- first heating means for heating said first and second electrode means to a first selected temperature;
- means for supporting said second backup means and second electrode means for movement toward and away from said first electrode means;
- second heating means for heating said feedstock and that part of said first and second electrode means contiguous to a feedstock work region between said first and second electrode means to a second selected temperature comprising means for applying an electric current through said first and second electrodes and said feedstock;
- control means for regulating the density of said current through said feedstock and the magnitude of said pressure exerted on said feedstock by said second electrode means so as to hold the feedstock temperature below its melting point but sufficiently high to produce in said work region a localized plastic flow zone in which said feedstock is in a plastic and flowable condition;
- and
- feeding means for moving said feedstock through said work region so as to cause said localized plastic zone to proceed uniformly along said feedstock.
A method for minimizing heat loss from the work rolls of an isothermal rolling mill of the type employing at least, one backup roll to drive each work roll at a contact line comprising the step of:
- passing a heating current through said contact line from said at least one backup roll to said work roll whereby the resultant heating at said contact line opposes thermal conduction loss from said work roll to said at least one backup roll.
Dependencies are inferred from the claim text.