Ferrite
Ferrite
While there is no direct correlation, with higher ferrite numbers ( >30) a factor of 0.7 can be applied to produce % ferrite.
Zanoni Ferrite was born in 1946, in So Paulo, SP, Brazil.
Pretty sure it is ferrite
You can measure the ferrite number of a steel using a Severn Gage, a mechanical device; or using a ferrite scope, an electronic device, available from several manufacturers.