By evaporating and neutralizing of two ammonium tungstate with different density ,crystals of ammonium paratungstate (NH1)10W12O11·Nh2o(n=11,7,5)were prepared with ultrasonic .UsingXRD,DTG and granularity analysis, the crystalline form was confirmed and researched .The results proved that the effect of ultrasonic on ammonium tungstate was in evidence .The crystalline forms were the same with ultrasonic and without ultrasonic, but impure apexes on the XRD patterns were less and value of d/A more tallied with literature with ultrasonic . Distributing of crystalline granularity became narrower and the crystal was more homogeneous. Ultrasonic shortened the formation time nucleus of crystal .

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A refractory metal tungsten carbide hard metal compound and a binder made by powder metallurgy method, its hardness (HRA) is 89 to 94, much higher than the high-speed steel; at 540 ℃ hardness (HRA) 82 to 87, and the hardness of high-speed steel normal temperature (HRA83 ~ 86) fairly, but also has good chemical stability, heat resistance advantages. Tool materials currently used for a lot of variety though, the new tool materials are also emerging, but still very popular tungsten carbide tool material kind.

In order to prevent the material as a result of crack propagation due to the failure, and is favorable for obtaining a high-performance tungsten carbide cutting tools material may gradient processing, the surface area of the coated substrate formed lack toughness cubic tungsten carbides and carbonitrides of region, this region is higher than the binder content of the nominal binder content of the coating substrate; when a crack is formed in the coating extended over the area, because of their toughness, crack propagation can absorb the energy, it is possible to effectively tungsten carbide cutting tools to prevent cracks internal expansion, improve the performance of tungsten carbide cutting tools.




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Ammonia in APT crystal mother liquor was removed by adding sodium tungstate with sodium hydroxide and magnesium salts. The results show that the content of ammonia in the treated solution can be removed down to 0.042g/L up to 98.8 ％ removal rate. The resultant sodium tungstate solution was diluted 10 times befote prepared as ion exchange feed solution., the content of ammonia in the raffinate is less than 0.0005％, which can meet China national discharge standard .

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The extremely sharp and smooth enough neat cutting edge machining to have a specific, smooth shape, and edge rounding mostly waterfall edge, this process is called edge passivation. tungsten carbide cutting tool edge passivation change the contours of the cutting edge and morphology, but also to improve the microstructure of the blade surface area, thereby affecting the cutting process, tool performance and workpiece quality. tungsten carbide cutting tool edge passivation impact, affecting mainly the following aspects: the distribution of cutting temperature, the size distribution of cutting force, stress and strain, and chip formation and chip flow, deformation region of the workpiece, the workpiece surface integrity (residual stress), the machined surface roughness, surface hardening process and tool wear resistance.

Edge passivation tungsten carbide cutting tools for working efficiency has an important role in the following cases generally require the tool edge passivation:
1. The new sharpening of tungsten carbide cutting tools or regrinding of tungsten carbide cutting tools.
2. Prior to the tungsten carbide coating.
3. When the impact of heavy-duty cutting or cutting edge tungsten carbide cutting tools needed to passivation.




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