Metal injection molding (MIM) technology is suitable for the preparation of high-precision products with complex shapes, uniform structure and high performance. It can realize automatic continuous production, high efficiency, and material utilization rate is close to 100%. Tungsten heavy alloy products are more and more widely used in military, medical and other industries. The shape requirements of the parts are more and more complex, the processing is difficult, and the production cost is high. The injection molding process can solve this problem well.
The process of manufacturing tungsten alloys using metal powder injection molding includes:
1. Ingredients: provide granular tungsten alloy feed with moisture content ≤0.2%. The tungsten alloy feed is mixed with tungsten alloy powder and organic binder. The tungsten alloy at least includes W, Ni, Cu, Fe , and Co, wherein the mass percentage of W in the tungsten alloy is greater than or equal to 85%, so that the density of the tungsten alloy reaches 16.5-19.0g/cm3.
2. Molding: The tungsten alloy feed is injected into the mold under the conditions of an injection temperature of 100-195°C, an injection pressure of 600-1800bar, and an injection speed of 30-140mm/s. The preferred injection cycle is 25s. The mold temperature of the mold is preferably selected to be 35°C, the holding pressure therein is selected to be 750bar, 750bar, and 100bar in turn, and the corresponding holding time is 0.2s, 0.8s, and 0.1s. According to the actual size of different products, the injection cycle, holding pressure and holding time need to be adjusted to form a defect-free tungsten alloy blank.
3. Solvent Degreasing: The tungsten alloy blank is placed in a water bath with a temperature of 25-45° C. for solvent degreasing for 8-24 hours, and the degreasing agent is n-heptane.
4. Atmospheric Thermal Degreasing: The tungsten alloy blank after solvent degreasing is placed in ammonia decomposition gas, and thermal degreasing is carried out in a pusher furnace with a maximum debinding temperature of 600-1000°C at a speed of 20-45min/boat for 10 -28h.
5. Atmosphere Sintering: The tungsten alloy blank after thermal degreasing is placed in ammonia decomposition gas, and sintered in a pusher furnace with a maximum sintering temperature of 1400-1500°C and a boat pushing speed of 20-45min/boat for 10-28h. After cooling, a high density tungsten alloy is obtained.
Tungsten alloy sintered by MIM has high density, high hardness, non-magnetic, low sintering temperature, and low thermal expansion coefficient, etc. performance.
Tungsten Heavy Alloy MIM Parts Photo
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