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Preparation method of tungsten rod

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Update time : 2023-03-06 15:55:00

Tungsten rods include tungsten rods, tungsten steel rods, sintered tungsten rods, mainly used to forge components into materials, cutting tools and slugs, light bulbs tungsten wires, electrical contacts and heat conductors, crankshafts and cylinders tungsten wire barrels, and various components of heat-resistant steel. Doped tungsten rods are used to produce filament or tube filament, which guarantees significant resistance to high temperatures. Pure tungsten is a natural metal mined from the ground. In its original form, pure tungsten is very brittle.

Tungsten is a rare non-ferrous mineral product in the world, the annual output is very low, very wide range of uses, mainly used for casting ingredients. Tungsten comes from a kind of white sand ore body with a very small ore line. After mining, grinding, water gravity separation, refining and other processes, tungsten ore powder with a grade of more than 95% is obtained, and then refined and formed by high-temperature electric furnace to produce the finished product is tungsten rod. Melting point of tungsten: 3500℃.

Preparation method:

1) Preparation of doped tungsten powder: raw tungsten (WO2.9) powder and mixed solution of H2SiO3 and KOH containing SIO2:0.2~0.6wt% and K2O: 0.2~0.6wt% and Al2O3: When 0.02~0.1wt% of Al (NO3)3 solution is placed in an agitator, mixed at 50~60℃ for 3~5 hours, and dried at 100~200℃ for 3~6 hours, doped blue tungsten powder can be obtained.

2) Reduction treatment: the doped tungsten powder is loaded into a boat and placed at 500~950℃ and H atmosphere for reduction treatment for 8~12 hours. After cooling, the doped tungsten powder is obtained through 100~200 mesh screens;

3) Pickling: Firstly, the doped tungsten powder was acid-washed with dilute hydrochloric acid with a concentration of 3~6wt% for 30~60 minutes, then the superliquant was removed, and then hydrofluoric acid with a concentration of 3~6wt% was added to wash the powder until Si content ≤250ppm and Al content ≤30ppm, and then vacuum dried at 70~150℃ for no less than 10 hours. After drying, 160~200 mesh sieve dispersing and removing impurities;

4) Pressed blank: the powder obtained from treatment 3 is pressed under 150~250MPa to make doped tungsten blank strip;

5) Pre-sintering: the pressed billet is placed in a boat and sintered in H atmosphere and temperature of 1100~1400℃ for 30~60 minutes;

6) Vertical melting sintering: the pre-sintered billet is placed in the vertical furnace. After 10~25 minutes of drooping melting and sintering under the condition of H atmosphere and the current intensity of 70~92% of the melting current, undense potassium-containing tungsten rods are obtained with furnace cooling;

7) Indirect sintering: the tungsten rod obtained from the sixth process is placed in an intermediate frequency furnace or a tungsten rod furnace, and sintered for 2~6 hours in a H atmosphere and at a temperature of 2000~2300℃. After cooling the furnace, the target metal tungsten rod containing potassium can be obtained.

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