METHOD OF PREPARING IRON SILICON ALLOYS WITH HIGH SILICON CONTENT FOR COLD WORKING REQUIRING DUCTILITY

摘要

1356342 Making sheet and foil; working at specified temperatures MANNESMANN AG 10 May 1971 [11 May 1970] 14098/71 Headings B3A and B3V [Also in Division C7] An ingot of silicon-iron alloy containing, by weight, 4À5-7À5% Si is hot-worked above 650‹ C. and the resulting product warm-worked in the range 650-350‹ C. so as to provide an intermediate product which can be cold-worked, avoiding raising the temperature above 350‹ C. In an example the hot ingot having a nitrogen content greater than 0À004% is stripped, inserted in a furnace at 650-700‹ C., heated to 1100‹ C., removed and descaled. It is then hotrolled with an end temperature up to 750‹ C. and the plate hot-divided and descaled at ambient temperature. Five mm. plates were then reheated to 650‹ C. and kept for at least one hour, and preferably from 3-7 hours, at 650‹ C. Further rolling followed during cooling in 15-20 passes down to a plate thickness of 1À5 mm. Alternatively, thicker plates (up to 8 mm.) were reheated to 850-900‹ C. and again hot-rolled, with intermediate heating at 870‹ C., down to 3À5-1À75 mm. Warm-rolling followed, and then cold-rolling down to below 1 mm. Plate thicknesses down to 0À03 mm. are referred to. Final annealing for magnetic properties is effected after working and blanking steps.