| 摘要 |
In a method of manufacturing single or multiple-coil recrystallized filaments from tungsten wire having an average crystal size of at least one turn of a single coil or, in the case of multiple-coil filaments, of a primary coil, the filament, prior to recrystallization is subjected, without a mandrel and either within or outside of an incandescent lamp, to a temperature between 1500 and 2000 DEG C. for at least 5 minutes to produce a far-advanced lattice recovery. The filament, the wire of which may contain 0.05 to 0.1 per cent of iron, may be heated to 1850 DEG C. for from 5 to 120 minutes. A formula is given correlating lattice recovery, time and temperature, and the heating should be such that recrystallization just does not occur. Recrystallization is produced later by heating in a tungsten furnace to 2400 DEG C. or the filament may be mounted in a lamp and burned. It is stated that filaments heated in this manner have a high resistance to vibration. |
