Method of constructing a magnetic core

Claim 1

A method of constructing laminations of an amorphous alloy, suitable for use in a magnetic core for static electrical inductive apparatus, to improve the core space factor, to reduce core losses, and to reduce the sensitivity of the amorphous laminations to core clamping pressures, comprising the steps of: cutting laminations from a strip of amorphous alloy, stacking said amorphous laminations, to provide a stack of laminations, said stacking step including the step of dividing said stack of laminations into a plurality of groups by interspersing rigid flattening sheets between the groups, with the surfaces of said rigid flattening sheets which contact the amorphous laminations being smoother than the surfaces of the amorphous laminations, and with the thickness dimension of each of said rigid flattening sheets exceeding the thickness dimension of each of said amorphous laminations, and subjecting said stack of amorphous laminations to a heating-cooling cycle which includes the steps of: heating said stack of grouped laminations to a predetermined temperature, below the crystallization temperature of the amorphous alloy, which temperature is sufficient to stress relief anneal the amorphous alloy, providing an inert atmosphere about said stack of amorphous laminations during said heating step, pressing said stack of grouped laminations during said heating step to provide a pressure of at least 4 psi, but below the pressure which would initiate metallurgical bonding of adjacent laminations, cooling said stack of grouped laminations, and applying a saturating magnetic field to said stack of grouped laminations, at least during a portion of said heating-cooling cycle.

Claim 2

A method of constructing laminations of an amorphous alloy, suitable for use in a magnetic core for static electrical inductive apparatus, to improve the core space factor, to reduce core losses, and to reduce the sensitivity of the amorphous laminations to core clamping pressures, comprising the steps of: cutting laminations from a strip of amorphous alloy, stacking said amorphous laminations, to provide a stack of laminations, said stacking step including the step of dividing said stack of laminations into a plurality of groups by interspersing rigid flattening sheets between the groups, with the surfaces of said rigid flattening sheets which contact the amorphous laminations being smoother than the surfaces of the amorphous laminations, and with the thickness dimension of each of said rigid flattening sheets exceeding the thickness dimension of each of said amorphous laminations, and subjecting said stack of amorphous laminations to a heating-cooling cycle which includes the steps of: heating said stack of grouped laminations to a predetermined temperature, below the crystallization temperature of the amorphous alloy, which temperature is sufficient to stress relief anneal the amorphous alloy, providing an inert atmosphere about said stack of amorphous laminations during said heating step, pressing said stack of grouped laminations during said heating step to provide a pressure of at least 4 psi, but below the pressure which would initiate metallurgical bonding of adjacent laminations, cooling said stack of grouped laminations, and applying a saturating magnetic field to said stack of grouped laminations, at least during a portion of said heating-cooling cycle.