Preparation method of large high density tungsten alloy counterweight

A tungsten alloy and counterweight technology, which is applied in the field of high-density tungsten alloy large-scale counterweight and its preparation, can solve the problems of low uniformity of internal and external density, affect the processing and use of counterweight, and a large number of pores, etc., to achieve low cost and meet density Requirements, organization uniform effect

Active Publication Date: 2014-06-18
北方材料科学与工程研究院有限公司 +1
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AI-Extracted Technical Summary

Problems solved by technology

However, due to the solid phase sintering process, it is difficult to achieve the ideal density of the large billet, so there are a large number of pores, looseness and other defects in the core of the billet, the uniformity of the internal an...
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Abstract

A preparation method of a large high density tungsten alloy counterweight is characterized by comprising the steps that: dividing the large counterweight into a plurality of small counterweights with the weight below 50Kg; compounding, by mass, the following components: 91%-95% of tungsten powder, 3.50%-7.5% of nickel powder and 1.0%-3.0% of iron powder; weighing the three kinds of raw material powder, mixing evenly and pressing into a small counterweight blank, then performing liquid phase sintering; processing the connection surfaces of the sintered small counterweights into flat faces, putting one of the small counterweights in a sintering boat, wherein the connection surface maintains horizontal or is vertical to the sintering boat, then putting another small counterweight with the connection surfaces of the small counterweight and the before small counterweight being attached, putting other small counterweights in the same manner, and finally putting all the small counterweights together with the sintering boat into a fixed-point type hydrogen furnace for liquid phase sintering. The large tungsten alloy counterweight prepared by the method is high in density and uniform in structure, the average grain size of the sintered counterweight is 30-50 mum, and the cost is low.

Technology Topic

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  • Preparation method of large high density tungsten alloy counterweight
  • Preparation method of large high density tungsten alloy counterweight
  • Preparation method of large high density tungsten alloy counterweight

Examples

  • Experimental program(3)

Example Embodiment

[0022] Example 1:
[0023] The manufacturing weight is 100Kg cylindrical counterweight, and the density requirement is 17.3g/cm 3 ±0.2g/cm 3.
[0024] Step 1: The cylindrical counterweight can be divided into two small counterweights of 50Kg to prepare;
[0025] Step 2: The components and their contents in terms of mass percentage are: Tungsten W: 91%, Nickel Ni: 6.3%, and Iron Fe: 2.7%. According to the mass percentage of the above powder raw materials, the average particle size of tungsten powder is 2.5μm~3.5μm, and the purity is ≥99%; the average particle diameter of nickel powder is about 1μm~3μm, and the purity is ≥99.8%; , Purity ≥99.5%; mixing in a mechanical mixer for 12h.
[0026] Step 3: Put the mixed raw material powder into a soft rubber mold, seal the rubber stopper, and press it in a wet-jacket cold isostatic press with a pressing force of 200 MPa and holding pressure for 3 seconds.
[0027] Step 4: The pressed billet is put into a fixed-point hydrogen furnace for liquid phase sintering, and the protective atmosphere is H 2 Or ammonia decomposition gas, 75%H 2 +25%N 2 , The sintering temperature is 1450℃, the heating rate is 5℃/min, and the holding time is 40min.
[0028] Step 5: Machining the end faces of the two sintered small counterweight cylinders into planes, and the surface roughness is guaranteed to be below Ra6.3. Then place one of the counterweights on the sintering boat, keeping the end surface level, and then place the other counterweight on the previous one, and place the two ends together without any obvious gap between the end surfaces. Finally, the two small counterweights and the sintering boat are put into a fixed-point hydrogen furnace for liquid phase sintering. Protective atmosphere is H 2 Or ammonia decomposition gas, sintering temperature 1450℃~1550℃, heating speed 5℃/min, holding time 30min~60min. Prepared tungsten alloy counterweight, material density 17.2g/cm 3 , The core material has a tensile strength of 850MPa and an elongation rate of 5%.

Example Embodiment

[0029] Example 2:
[0030] The manufacturing weight is 150Kg cylindrical counterweight, and the density requirement is 17.6g/cm 3 ±0.2g/cm 3.
[0031] Step 1 The cylindrical counterweight can be divided into three small counterweights of 50Kg to prepare;
[0032] Step 2 The components and their contents in terms of mass percentage are: Tungsten W: 93%, Nickel Ni: 5%, and Iron Fe: 2%. According to the above-mentioned powder raw materials, the average particle size of tungsten powder is 2.5μm~3.5μm, and the purity is ≥99%; the average particle diameter of nickel powder is about 1μm~3μm, and the purity is ≥99.8%; the average particle diameter of iron powder is about 1μm~3μm. , Purity ≥99.5%; mixing in a mechanical mixer for 12h.
[0033] Step 3: Put the mixed raw material powder into a soft rubber mold, seal the rubber stopper, and press it in a wet-jacket cold isostatic press with a pressing force of 200 MPa and holding pressure for 3 seconds.
[0034] Step 4: The pressed billet is put into a fixed-point hydrogen furnace for liquid phase sintering, and the protective atmosphere is H 2 Or ammonia decomposition gas, 75%H 2 +25%N 2 , The sintering temperature is 1450℃, the heating rate is 5℃/min, and the holding time is 40min.
[0035] Step 5: Machining the end faces of the three sintered small counterweight cylinders into a flat surface, and the surface roughness is guaranteed to be below Ra6.3. Then place one of the counterweights on the sintering boat, keeping the end face level, and then place the other counterweight on the previous one, and place the two ends together without any obvious gap between the end faces. The parts are also placed on the upper part of the second part, and finally the three small counterweights and the sintering boat are put into a fixed-point hydrogen furnace for liquid phase sintering. Protective atmosphere is H 2 Or ammonia decomposition gas, 75%H 2 +25%N 2 , The sintering temperature is 1450℃~1550℃, the heating rate is 5℃/min, and the holding time is 30min~60min. Prepared tungsten alloy counterweight, material density 17.45g/cm 3 , The core material has a tensile strength of 830MPa and an elongation rate of 5%.

Example Embodiment

[0036] Example 3:
[0037] The manufacturing weight is 300Kg cylindrical counterweight, and the density requirement is 18.0±0.2g/cm 3.
[0038] Step 1 The cylindrical counterweight can be divided into six small counterweights of 50Kg to prepare;
[0039] Step 2 The components and their contents in terms of mass percentages are: Tungsten W: 95%, Nickel Ni: 3%, and Iron Fe: 2%. According to the above-mentioned powder raw materials, the average particle size of tungsten powder is 2.5μm~3.5μm, and the purity is ≥99%; the average particle diameter of nickel powder is about 1μm~3μm, and the purity is ≥99.8%; the average particle diameter of iron powder is about 1μm~3μm. , Purity ≥99.5%; mixing in a mechanical mixer for 12h.
[0040] Step 3: Put the mixed raw material powder into a soft rubber mold, seal the rubber stopper, and press it in a wet-jacket cold isostatic press with a pressing force of 200 MPa and holding pressure for 3 seconds.
[0041] Step 4: The pressed billet is put into a fixed-point hydrogen furnace for liquid phase sintering, and the protective atmosphere is H 2 Or ammonia decomposition gas, sintering temperature 1480℃, heating speed 5℃/min, holding time 50min.
[0042] Step 5: Machining the end faces of the six sintered small counterweight cylinders into a flat surface, and the surface roughness is guaranteed to be below Ra6.3. Then place one of the counterweights on the sintering boat with the end face vertical, and then put the other counterweight and the two ends of the previous one together without any obvious gap between the end faces. The other four pieces are used Place them in the same way, and finally put the six small counterweights together with the sintering boat into the fixed-point hydrogen furnace for liquid phase sintering. Protective atmosphere is H 2 Or ammonia decomposition gas, 75%H 2 +25%N 2 , The sintering temperature is 1550℃, the heating rate is 5℃/min, and the holding time is 60min. The prepared tungsten alloy material has a density of 17.95g/cm 3 , The core material has a tensile strength of 800MPa and an elongation of 3%.
[0043] The large-scale tungsten alloy weight prepared above was taken from the core and observed under a metallurgical microscope at 100 times. No obvious pores, looseness and other defects were seen. Sampling at the joints and other locations for mechanical performance testing can also reach the conventional mechanical performance level.
[0044] According to the method of the present invention, a large-scale counterweight can be manufactured from raw material powders of tungsten, nickel, and iron. The average relative density of the large-scale counterweight is greater than 98%, and the relative core density is greater than 97.5%. The average relative density should be understood as the average density relative to the weight per unit volume. For those skilled in the art, the large-scale counterweight should be understood as a weight above 100Kg, and the core density should be understood as the density of the central area of ​​the counterweight. The core of the present invention is a portion of 10% of the relative total volume of the central area of ​​the counterweight.
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PUM

PropertyMeasurementUnit
Density17.2g/cm³
Tensile strength850.0mPa
Density17.4g/cm³
tensileMPa
Particle sizePa
strength10

Description & Claims & Application Information

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