抄録
Fe-Co system alloys used for telephone receiver diaphragm, called by the name “Permendur”, must be cold-rolled easily to very thin sheet, but generally Fe-Co alloys are brittle and cannot be cold-rolled readily. When a few percent of vanadium was added by quenching from about 900° without influencing the magnetic properties, it can be cold-rolled.
Mechanical properties such as hardness, elongation, tensile strength and etc. vs. quenching-temperature curves increase all from about 600° and attain a maximum at about 700∼1100°. It is inte resting to note that hardness has a maximum at 800°.
Fe-Co (50%) alloys has FeCo superlattice, This in confirmed by X-ray analysis. But on the contrary to Ni-Fe (38.5%Ni) alloy, its magnetic properties decreases by quenching : Fe-Co (50%)-V(2%) alloys has decreased after quenching, and the magnetic properties vs. quenching-temperature curve has conspicuous features. By varying Co% at constant V%, the excellence of 50%Co alloy was confirmed. About this alloy B-H curves were measured at various annealing temperature, annealing time. After this alloy was cold-rolled its magnetic properties increases generally. This alloy has strong direction dependency measured by torguemeter after cold-rolling, but when annealed, it vanishes perfectly.
