GB1174947A - Magnets and Components thereof - Google Patents

Abstract

1,174,947. Working at specified temperatures. HITACHI Ltd. 9 March, 1967 [16 March, 1966], No. 11093/67. Heading B3V. [Also in Division C7] A magnet or component thereof is made from a material containing 0À07 to 0À12% by weight of iron with or without alloying components, the material being fully killed and of non- metallic inclusion content such that the areapercentage thereof is less than 0À1, and having been annealed at a temperature above the alphagamma transformation range. Alloying elements permissible may include nickel or cobalt in an amount which does not cause a large reduction in the incremental permeability, or molybdenum, chromium or tungsten in an amount less than 1%. As exemplified a material was made up from pure iron and a white pig-iron ; after forging at 950-1050‹ C. it was annealed at 950‹ C. In a further example, ingots were forged at 950‹ to 1050‹ C. with a ratio of about 10, followed by annealing at 600‹ to 1000‹ C., while in a still further example an ingot was die forged with a forging ratio of about 10 to form a billet about 170 mm. in diameter by 500 mm. long; the latter was then forged at 1000‹Œ50‹ C. to 300 mm. diameter by 160 mm. long and annealed for 2 hours at 950‹ C. followed by cooling in air. After polepieces had been cut to shape, they were finally annealed at 550‹ C. for 6 hours.