Preparation of Irregular Special-Shaped Parts with Pure Tungsten Powder

With the development of electronic industry, the demand for pure tungsten special-shaped parts is increasing. Tungsten shaped parts are of great importance in aerospace, military industry and nuclear industry. Especially in the field of semiconductor technology, Bluetooth, Wi-Fi, 3G and other applications are booming. The ion implantation machine is the main equipment for the production of semiconductor crystal garden. 

The 30% parts of the arc reaction chamber of the ion implantation machine are made up of tungsten metal finishing work. Therefore, the irregularly tungsten parts have irreplaceable use in the IP industry. However, the process of using tungsten powder to process special-shaped parts is more complicated. Therefore, this paper briefly introduces the general process of preparing tungsten alloy powder from special-shaped parts.

1.The mixing of tungsten powder: the ball mill is used to mix the reduced tungsten powder evenly, the speed of ball mill is 10-30 rpm, and the mixing time is 8-16 hours.

2.Isostatic pressing: the fluid medium is pressed into the high pressure steel body sealed container with the help of the high pressure pump. The static pressure of the high pressure fluid directly acts on the powder in the elastic die sleeve. The powder body is evenly compressed in all directions at the same time in the same time, and the density distribution is uniform and the strength of the high pressure is made. The pressing pressure is 1000Kg/cm^2-2200Kg/cm², and the holding time is 30 minutes -60 minutes.

3.Tungsten products sintering: sintering temperature heating process system is adopted, heat preservation for 2 hours at 800 C -1000 C, to remove low melting point material and oxygen content, heat preservation at 2200 centigrade for 4-8 hours, the total sintering time is 20 hours -26 hours / furnace, and the protection gas is hydrogen;

4.The hot forging of tungsten plate, rod and block is processed through the hot pressure of tungsten sintered blank. The purpose of hot forging is to improve the structure and improve the comprehensive properties of tungsten metal. The heat process is followed by the principle of one fire and one process, and the deformation of the final forgings is more than 80%.

5.Process annealing: in the hydrogen protected molybdenum wire furnace, the tungsten products processed by hot pressure are removed from the internal stress annealing treatment. The annealing temperature is 900 -1200 C, and the heat preservation time is 2 hours -4 hours.

6.Elimination of tungsten products stress source processing: under 10-20 times magnifying glass, check whether tungsten products have detonation angle, and whether there are pits and cracks on the surface of tungsten products.

7.Tungsten product electric pulse processing: in the process of processing, the spark discharge between the tool and the workpiece is produced continuously, and the heat of the partial transient heat is removed. The processing voltage is 20V-25V, the processing current is 6A-10A, the processing pressure is 5Mpa-6Mpa, the rotation speed is 20-120rpm, the pulse width (Ton) is 4, the pulse tip ratio (Toff) 1, the power pipe is 3 -6.

8.Tungsten wire cutting processing: the basic principle of WEDM is to use moving copper wire or molybdenum wire as electrodes to discharge and cut the workpiece by pulse spark and cutting.

Machining center processing: processing technology involves two aspects of numerical control processing technology and numerical control programming technology, in which cutting tools are specific, and the choice of tool path and processing parameters is determined by the technical requirements of the workpiece.

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