Process of producing semi-hard magnetic materials

A process of producing semi-hard magnetic materials having square hysteresis loop characteristics which comprises the steps of:

• process annealing an alloy material consisting, by weight, of 73 to 93% cobalt, 1 to 5% niobium and the balance consisting essentially of iron, at a temperature of not lower than 900.degree. C,
• cold working said annealed alloy material at a reduction in area of not less than 75%;
• and
• thereafter subjecting said cold worked alloy material to a combination treatment including one or more stress-relief annealings at a temperature of 500.degree. to 700.degree. C for a period of time not longer than 10 minutes selected so that no intermetallic compound precipitates in said alloy material, and one or more additional aging steps at a temperature of 600.degree. to 900.degree. C for a period of time not shorter than 30 minutes selected so that an intermetallic compound precipitates in said alloy material.