GB548982A - Magnetic alloy of iron and aluminium - Google Patents

Abstract

548,982. Heat treatment of magnetic iron alloys. STANDARD TELEPHONES & CABLES, Ltd. Aug. 1, 1941, No. 9798. Convention date, Aug. 7, 1940. Drawings to Specification [Classes 72 and 82 (i)] [Also in Group XXII] The magnetic properities of iron alloys containing 2 to 10 per cent. of aluminium are given a high permeability and directional properties by rolling or elongation while cold. This may be followed by heat treatment, e.g. heating, to 600‹-1425‹C. Sheet alloy containing 3.5 per cent. of aluminium may be reduced by hot rolling to a thickness of 0.35 inch and then by cold rolling to 0.109 inch or a rod may be reduced by hot rolling to 0.5 inch diameter and then by cold rolling to 0.25 inch. The product may be heated to 1000‹C. in hydrogen or in a sealed pot for one hour and cooled slowly. Long heating at over 1300‹C. lowers the permeability at high flux densities though it may increase the maximum permeability. Data are given of magnetization, coercive force, permeability, hysteresis loss and torque of sheet or rod made from alloys containing 3.5 and 4 per cent. of aluminium hot rolled at different temperatures before the cold rolling and annealed at different temperatures within the range specified. The alloys thus treated are stated to have the tractive force of iron, e.g. when used in relays, and the high speed of response of iron alloys containing 45 per cent. of nickel.