Method for producing tungsten bar serving as halogen tungsten lamp tungsten filament

Abstract

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.

Description

technical field [0001] The invention relates to tungsten powder metallurgy technology, in particular to a method for preparing tungsten bars used for making tungsten wires of halogen tungsten lamps. Background technique [0002] With the rapid development of my country's automobile industry, electronics industry, and aerospace industry, the demand for tungsten-halogen lamps is growing at an annual rate of 20%. Tungsten-halogen lamps are mainly used in lighting systems in the above-mentioned industries. Tungsten-halogen lamps have the characteristics of shock and vibration in the use environment, so it is required that the recrystallization structure of the core material - tungsten wire can form a good dovetail lap structure, and the aspect ratio is greater than 12, that is, the high-temperature strength is high under high-temperature ignition state, Good anti-sag performance and anti-deformation performance under high temperature. The production process of tungsten wire is...

AI Technical Summary

Problems solved by technology

my country's tungsten wire production technology started relatively late, and the production line of tungsten wire for halogen tungsten lamps is still blank in China. With conventional technology, the production line of ordinary tungsten wire can only obtain medium and low-grade tungsten wire for halogen tungsten lamps, resulting in finished products Low efficiency and high production cost; at the same time, due to the low recrystallization temperature and small aspect ratio of this kind of tungsten wire for halogen lamps, it has low high-temperature strength, poor high-temperature sag resistance and deformation resistance, short service life, and high quality. There is a big gap with foreign products. At present, domestic demand is mainly met by importing high-priced tungsten-halogen lamps or tungsten wires for tungsten-halogen lamps from abroad.