Tungsten Copper Electrode New Process

With the rapid development of EDM (Electrical Discharge Machining) industry, it has higher and higher requirements for the used electrode. Both tungsten copper with high content of W (mass fraction of W reaches 50%-90%) and tungsten copper with high content of Cu (mass fraction of Cu reaches 60%-90%), the most widely used are mixing method and infiltration method. Theoretically, the mixing method has simple operations and can fabricate tungsten copper products with any ratio of W and Cu. But the powder grain of raw material by this kind of conventional process is too large and the density distribution is uneven, which is difficult to fabricate tungsten copper electrode with compact structure after pressing and sintering process.

While the infiltration process is suitable to fabricate tungsten copper with 8%-40% content of Cu, tungsten skeleton infiltrated by copper in molten state to obtain the densification. Although the infiltration process is the most widely used in tungsten copper electrode now and it has stable working properties, it also has some problems, such as many controlling parameters, difficulties in porosity controlling, difficulties in porosity distribution and so on. So the relevant scholars and researches have further explosion surrounding the raw material preparation and molding process in recent years. Some new technology has gradually developed, which is more practical and operational effects are:

1. Pre-alloying: Its powder refinement and even micro-alloying, so as to achieve increased activity and split the purpose of promoting densification by mechanical and high energy ball milling;

2. Ultrafine particle / nano powder: By the addition of grain growth inhibitors, high-energy ball milling, adding elements and changing the material of the powder form and other methods to refine, even to the nanometer level;

3. Thermoforming: it is pre-loaded with a good blend in the mold cavity, rapid molding under heat and pressure to achieve integration and briquettes pressed sintered compact so as to achieve the densification effect;

tungsten copper electrode

 

Diesel Engined Car Exhaust WO3 Denitration Catalyst

diesel engined car exhaust WO3 denitration catalystOxide catalyst is mainly the vanadium based catalyst, and adding co-agents like tungsten trioxide, such kind of catalyst has a high NOx removal efficiency in the temperature range of 300-400°C with excellent stability. In the past, the catalyst of diesel engined car exhaust is primarily the noble metal catalyst, but its application is limited by high cost. An invention has pointed out that a method for preparing the diesel engined car exhaust tungsten trioxide denitration catalyst which has a high catalytic activity, wide temperature window, as follows:
 
1. Calcine carrier of the titanium dioxide at 300-400°C for 2-5 hours;
2. Preparation of the active ingredient solution: dissolve the ammonium metavanadate and ammonium metatungstate in deionized water, then add the appropriate amount of oxalic acid solution and uniformly stirred, to obtain the active catalyst component solution;
3. Impregnation method to load the active component: The carrier is immersed in the calcined active component solution prepared in step 2;
4. Natural drying the catalyst obtained in step 3, then transferred to drying conditions at 80~120°C for 8~12 hours;
5. After drying, the catalyst is calcined at 300~600°C for 2 to 5 hours, then heated to 680-800°C and continually calcined for 2 to 5 hours to obtain the tungsten trioxide denitration catalyst which is suitable for diesel engined car exhaust.
Noted: wherein the carrier is titanium dioxide which takes 90-99.5% of the mass of catalyst; the main active component vanadium pentoxide takes 0.5-10%; additive- tungsten trioxide takes 0.5-10%.
 
The preparation method of this catalyst without introducing any chemical agent, just by changing the preparation process; by changing the calcining temperature to improve the distribution of the active component in the catalyst support surface, has the advantages of simple operation, excellent repeatability, easy to optimize the size and modifying the conventional catalyst.

 

What Is Stamping Tungsten Boat?

Stamping is also divided into forging, ginning, combining and other types. Processing of iron can be referred to as punching. Conventional press working method is cut, bent, twist. Also there are a variety of molds, including plastic, rubber molds, glass molds. Stamping dies are used for stamping, including arbitration die, progressive die, compound die, precision die, drawing die, bending die, molding, die cutting and other types of stamping dies, according to the differences of the finished product, users can choose different stamping dies.

At the beginning of it, tungsten plate should be blended into a certain angle, or bending the blended workpiece again. After that, it should be pressed into any hollow shape by mould, or bending the hollow mould workpiece further deformation. Afterward the hole or the outer edge of tungsten plate should be folded into a straight wall by mould. Forcing an outward radial force on the hollow member by mould, so that the local diameter can be expanded. After expansion, pressing the outside-in radial pressure on the hollow member so to narrow the local diameter. Next, putting the bloom into the die cavity, squeeze it out from the gap of mould to form the hollow or solid workpiece. Roll the panel into a ball peen whose shape approximate to a close one. Finally, press the bended or stretched workpiece into a right stamping tungsten boat shape.

The main features of the stamping W-boat is the high rate of final products. Because that this type of W-boat stamping tungsten boatadopting the stamping equipment and stamping mould, the accuracy of size and shape the stamping wolfram crucible are much higher. What’s more, it has a long life time and it is not easily to be damaged, therefore, the shape of the stamping tungsten boat from the same production batch is almost the same whose quality is also stable. However, during the stamping process, the device will produce noise and vibration which would have a great influence on operators. Furthermore, the mould is an essential material for stamping process, so the quality of the mould determines the quality of the W-boat.

Surface and internal performance of panel have a great impact on the quality of the finished product by stamping, it requires that the thickness of stamping material should be precise and without any spots, scars, bruises, surface cracks.

WO3 Denitration Catalyst Regeneration - Bubble Flow Device Method

WO3 denitration catalystIn the running, tungsten trioxide denitration catalyst will part or entire inactivated due to the fly ash poisoning and deposition of solids ect., and end its life after a certain period of time (approximately 2 to 5 years), therefore needs to be regenerated or obsolete processed. The bubble flow device (Air Lift Loop Reactor) can recover the activity of honeycomb SCR catalyst which deactivated from heavy metal poisoning in fly ash and solids deposition pollution ect. to the activity before polluted.
 
Most honeycomb-type SCR catalysts take titanium dioxide as the carrier, with the main active ingredient of organic and inorganic binders of vanadium (1~3%) and tungsten (10-20%). Experiment uses the mixture solution of sulfuric acid, ammonium vanadate and ammonium paratungstate to carry out the catalyst regeneration by bubble flow device, which the steps are showed as bellows.
 
1. Install the inactivated tungsten trioxide denitration catalyst in the bubble flow device, then washing for about 1 hour with the mixture solution of sulfuric acid which generated by pure water at room temperature, ammonium vanadate and ammonium paratungstate;
2. Dry the washed catalyst at a high temperature of 200°C in the air;
3. Calcined to obtain the regenerated tungsten trioxide denitration catalyst.
 
Remarks:
1. When weight content of the active ingredient- vanadium pentoxide less than 1.0%, the NOx removal rate is very low; however, when it reaches 10% or more, the NOx removal will decline rapidly at the high temperatures above 400°C, and promote the oxidation of sulfur dioxide, therefore, the selection of ammonium vanadate solution shall base on the vanadium pentoxide content which is controlled among 1.0~10%.
2. When the content of active ingredient- tungsten is higher than 20%, the oxidation of sulfur dioxide will be promoted, and the price is very expensive, therefore, the selection of appropriate concentration of ammonium paratungstate solution will be suggested to the economic.

 

AJ Carbon Sulfur Analyzer and Tungsten Granule

Jena Analytik Jena AG brand, called AJ, was established in 1990 in Germany, which is evolved by Carl Zeiss Carl -Zeiss Jena GmbH. Nowadays, AJ carbon sulfur analyzer has become one of the most popular brands of analytical instruments in Germany. The brand is mainly focus on the development, design and manufacturing of total organic carbon (TOC) / total nitrogen (TN) analyzers, organic halogen compounds (AOX) analyzer elements (C, S, N, Cl) analyzer, atomic absorption spectrometer (AAS), ICP-OES emission spectrometers, inductively coupled plasma mass spectrometry and UV / visible (UV / VIS) light meter points and biochemical analytical instruments. Analytik Jena is a provider of analytical measuring technology, and life science instruments. With its core expertise in optical spectroscopy and elemental analysis its portfolio includes analytical systems for qualitative and quantitative analysis of liquids, solids, and gases. 

Multi EA S® 5000 Elemental Analyzer is launched by AJ brand in 2008, which is a kind of multi-element professional analysis system for the analysis of total nitrogen, total carbon, total sulfur, total chlorine content of a variety of gaseous, liquid, LPG, solid samples. The instrument has many excellent features. Tungsten granule is used as the mainly flux, which can the accelerate reaction rate for the analysis process, shortening the time of determination. Its appearance and structure design is the main attraction, users can select the elements to be analyzed and the corresponding detector.

In the software you can choose to switch carbon and sulfur analysis, without any mechanical conversion. In addition, AJ carbon sulfur analyzer is a lightweight instrument, which does not require any maintenance vertical injector and a vertical furnace, so that it can ensure that good reproducibility of the instrument. After installation is completed, it doesn’t need any manual adjustment. Voltage stabilizing system in the gas circuit is equipped to avoid the pressure fluctuations while detecting. Any parameters of instrument are set and optimized and controlled by computer, which has the characteristics of full intelligence and full automation. Because the instrument has a heated filter device, there is no need for membrane dryers and detection system to be maintained repeatedly, which can greatly reduce operating costs.

tungsten granule and AJ carbon sulfur analyzer

 

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