The invention provides a method for producing a
tungsten bar serving as a
halogen tungsten lamp
tungsten filament, comprising the following steps of: material selecting, pre-reducing, high
potassium doping, reducing, acid rinsing,
powder preparing, cold static pressure shaping, high temperature
sintering and the like. Compared with the conventional technology, the method is characterized in that two
crystal ammonium paratungstates are utilized to prepared raw materials, high
potassium doping is adopted, preparation of middle granule tungsten
powder is added, a
powder distribution scheme is optimized by the middle granule tungsten and a unique incipient fusion high temperature
sintering process is utilized. In the method, the
granularity distribution of the tungsten powder avoids the peak or double peak phenomenon and has good normal distribution, after being sintered at high temperature, the cross section
crystal of the tungsten bar is thin and uniform; the tungsten bar is pressed by a powder mixing scheme; according to a forming mechanism of
potassium foams, the number of tungsten bar cross section
crystal grains is increased; and the partial growth of the crystal grains is avoided so that the potassium foam is small in aperture, large in density, multiple in crystal boundary, long in line and uniform in distribution.