Tungsten powder and rare earth oxide powder after pressing, tungsten blanks’ density and strength have been greatly improved. After pressing, the blanks should to process sintering. The sintering process will affect tungsten blank’s density, grain size, distribution of rare earth oxides and high temperature evaporation loss quantity and so on, thereby affecting the performance of the tungsten electrode. In the sintering process, time, temperature, heating gradient, heating rate and purity are the main factors affecting the properties of sintered blanks.

When the powder particles is small, if the sintering temperature is too high, the tungsten grain will grow dramatically and will reduce the matrix diffusion coefficient of rare earth oxides in tungsten matrix, increasing electrode’s fare damage rate. Besides, high sintering temperature will lead to low-melting material aggregation, increasing segregation and rare earth oxides loss, so rare earth oxides distributed in the tungsten matrix is unevenly. Meanwhile, the sintering temperature is too high is prone to produce anti-sintering phenomenon, so that tungsten blanks density will decline. Because during the multi-component series sintering, the densification is based on diffusion, with the sintering temperature increase, the diffusion coefficient increases as well, and the shrinkage of sintered blanks become slow. When the sintering temperature is too low, the sintered density of the tungsten electrode can reach requirement also affect the using results.

After using two-steps hydrogen reduction method reduced the tungsten powder and rare earth oxide powder, to process pressing. During pressing process uses steel mold pressing method. Tungsten powder and rare earth oxide affected by the pressing pressure, it will produce a series of displacement. Fine tungsten powder has smaller particles which can fill in the large grain tungsten powder, so tungsten powder particles to be re-arranged, resulting in doped tungsten powder volume greatly reduced. Besides, tungsten blanks density and strength are greatly enhanced. In addition, the tungsten powder particles under pressing pressure, the contact area between the particles is increase and the gap between the particles is reduce, increasing the cohesion between the powder particles, thereby improving the mechanical bite force between the powder particles, so the density and strength of tungsten blanks will be further improved. In the pressing process, the pressure is about 8.5Mpa.

Tungsten electrode is a refractory insoluble metal, so the sintering temperature is very high and usually uses self-resistive heating, namely, direct sintering method. During sintering, the sintering current is generally selected 90% fusing current, so this method is also called sintered sintering method. Sintering process will affect tungsten electrode’s density, grain size, rare earth oxides distribution and high temperature evaporation loss quantity and so on. And there are many factors affect sintering process, such as time, temperature, heating gradient, heating rate, powder purity. To well control these factors can obtain good performance sintered tungsten blanks, to produce good performance tungsten electrode.

Sintered tungsten blanks performance testing, we can observe the blanks surface color and surface defects, and you can also test blanks absorbent. Besides, you can also use drainage method to measure blank’s density. 

Generally used for machining hardened tungsten carbide slotting cutters were tested negative rake angle form the top edge so that both sides of the cutting edge blade angle to obtain the corresponding negative, slotting process will have beveled cutting characteristics. By increasing the negative rake angle cutting method to improve depth profile shaper cutters nose and the side edge chipping capacity and wear resistance. And this feature is not only suitable for cutting hardened hobbing, but also for slotting process. In order to maintain tungsten carbide slotting cutter based on the accuracy of the tooth to improve the cutting performance, the former top general use -5 ° blade angle is appropriate.

The flank of tungsten carbide slotting cutter is helicoid, which only in its truncated plane will have involute. However, when tungsten carbide slotting cutter made front corner and rear corner, the cutting edge will deviate from the cut surface, the shape with the theoretical involute is there are some errors, and this error is difficult to measure directly. So this will be difficult in the grinding process, the shape of the cutting edge will be further amended, and the need for tungsten carbide slotting cutter pressure angle correction.

In addition, in order to break through the conventional configuration (cone) tungsten carbide slotting cutter easily to be chipped, slotting low accuracy, the researchers also tried a new configuration of tungsten carbide slotting cutter for profiled convex instead of the traditional cone and as a shaper cutter teeth rake. As a cross-section will make a substantial increase in the absolute value of negative rake angle; curved front flank and the lateral flank cross a certain line in both the conical surface of the corner, so that the side edge space curve to flatten in case of the distortion caused by difficult control of the shape of the curve in space of cutting edge and ensure the cutting performance and surface quality. Overall, shaped convex curved tungsten carbide slotting cutter effectively solve the contradiction between the traditional configuration exist in the configuration tool and precision, thereby increasing wear resistance and chipping capability resistance.

From the appearance, slotting cutter is like a gear or a rack, which is widely used in fabricating spur and helical cylindrical gear meshing inside and outside. Especially for Multi-gear, herringbone gears and gear with a shoulder and shaped workpieces can be made by the slotting cutter with special structure, such as cam, internal spline and so on. According to the appearance, slotting cutter can be specifically divided into disc-shaped, tubular, bowl-shaped and taper shank type, and every shape of slotting cutter will correspond to the workpiece with different shape.

Disk-shaped gear shaper cutters are mainly used inside and outside straight tooth meshing, helical and herringbone gears; Cylindrical gear shaper cutters can be used in the processing module and a relatively small external gear; Bowl-shaped slotting cutter for multi-linking internal and external engagement with shoulder machining spur gears, the clamping nut at work can be accommodated in the body shaper cutters, which does not interfere with the cutting process carried out; Taper shank shaper cutters are mainly used in the processing and spur gear meshing helical gears. At present, in the actual production, high-speed steel is the most used material in slotting cutter, but there here are many studies have shown that compared with carbide shaper cutters with better performance. Especially in the hardness, the strength and wear resistance, tungsten carbide slotting cutter has a great improvement.

Tungsten granule is a flux which is major applied to the high frequency infrared carbon and sulfur analyzer. Therefore, tungsten granule also known as tungsten flux or pure tungsten flux. After processing the tungsten metal into some tiny particles, tungsten flux can be produced. The purity of tungsten granule is very high, it can reach more than 99.95%. And the size of tungsten granule is 20-40 mesh. As a flux, tungsten granule has good fluxing effectiveness and a stability analysis. Tungsten granule has been widely applied to the electronic chemical industry.

The shape of tungsten granule is polyhedral particles with bright gray color. Tungsten granule is mainly made of above tungsten. Tungsten is easily oxidized into tungsten oxide which belongs to acidity element and benefits the release of carbon dioxide and sulfur dioxide. In 1781, tungsten is a kind of mineral which was found by the Swedish chemist and mineralogist named Clance Tate.

There exist very low impurity elements in tungsten granule. The carbon element is less than 0.0008%, the sulfur element is less than 0.0005%, and an oxygen element is less than 0.05%. Therefore, tungsten granule has a high purity. In the most cases, tungsten granule is packed 1000g a bottle. The weight would be different due to the different specifications.

With the rapid development of modern science and technology, according to the demand of the production process, tungsten granule is widely applied to metallurgy, welding, and other analytical testing process. Nowadays, tungsten flux is the most indispensable fluxing materials for Infrared analyzer or other analyzers to measure the content of carbon and sulfur. It would release about 195.8 kcal / mol of heat when it start to oxidized with oxygen under a temperature greater than 650 ℃. Therefore, it has a strong fluxing effectiveness.

The main application of tungsten granule is to analyze the Infrared carbon and sulfur oxide. The tungsten granule can also be applied to analyze the content of the carbon and sulfur of iron or metal. As a flux, the characteristic of tungsten granule is stability, and it can also reduce the melting point of comburent or promote the release of carbon and sulfur.

Tungsten particles can also be used as an additive in Infrared carbon and sulfur analyzer. The characteristic of Infrared carbon and sulfur analyzer is a high instantaneous heating, besides, the speed of its reaction is fast. Tungsten granule not only acts as a flux, but also adjusts the PH (potential of hydrogen) of the medium. In addition, the tungsten granule also has many other effects, such as stirring and anti-jamming. The tungsten granule of Infrared carbon and sulfur analyzer can make the values of carbon and sulfur more accuracy, so most Infrared carbon and sulfur analyzer consider tungsten granule as an additive.

With the rapid development of tungsten industry, tungsten granule industry has been widely applied in many fields. However, there are still many problems in applications of tungsten granule. For example, the utilization of tungsten granule resources is lower, and the irrational exploitation of tungsten would cause the ecological environment pollution. To solve these problems, enterprises should improve the recycling of tungsten granule.