GB452497A - Improvements in the treatment of iron-silicon alloys - Google Patents

Abstract

The magnetic properties of iron silicon alloys are improved by subjecting the alloys to substantial deformation, e.g. to the extent of at least 40 per cent, in the cold or at a relatively low temperature and then annealing for a period of hours, e.g. from 4-100 hours, at 1000-1300 DEG C., in a protecting gas such as pure hydrogen. The alloys usually contain 0,5-5,0 per cent of silicon but with higher silicon contents the deformation may be effected at an elevated temperature, e.g. 100 DEG C. Intermediate annealing, e.g. at 800 DEG C. for 1/2 hour may be employed if the cold working takes place in steps. When the alloys are used in strip or bar form for the manufacture of ring cores, the strips &c. after the deformation may be built into rings of the desired shape to prevent sticking, separated by thin layers of clay, lime, &c. The rings so produced are then annealed.