Loss ferromagnetic materials and methods of improvement
AssigneeWestinghouse Electric Corp.
InventorsRobert F. Krause, Gary C. Rauch
Life of this patent
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Abstract
It has been found that ferromagnetic sheet material can be scribed in order to reduce watt losses by a thermal method involving rapid heating of small areas or narrow bands of the material in a manner that produces sudden thermal expansion to a degree sufficient to produce plastic deformation within the thermally treated zone. This method has been found to be particularly applicable to electrically insulative coated ferromagnetic sheet wherein it has been found that a laser operating in a continuous wave or extended pulse mode can produce the desired deformation in the ferromagnetic material without damage to the coating properties.
Claims15
A process for improving the watt losses and reducing the permeability in a ferromagnetic sheet material, wherein said process comprises the steps of:
- repeatedly traversing a laser beam across the width of said ferromagnetic sheet at spaced intervals along the length of said ferromagnetic sheet;
- said laser beam rapidly heating narrow bands of said ferromagnetic sheet to a temperature below the solidus temperature of said material;
- immediately thereafter rapidly self-quenching said narrow bands of material so heated;
- and wherein plastic deformation is produced in said narrow bands, causing the AC watt losses and AC permeability of said ferromagnetic sheet to be reduced, and wherein said AC permeability is reduced by between about 20 and about 52% at an induction of about 13 to about 17 kG.
Dependencies are inferred from the claim text.