The tungsten crucible crack analysis is quite important. If the problem that the bottom of crucible easily cracks is not solved, it will directly affect the yield of the crucible. Although powder metallurgy method producing crucible has many advantages including greatly saving metal consumption and reducing production cost, there are still many technical problems to be solved such as the bottom of crucible easily cracking.

What is tungsten crucible? It is made by turning and welding with tungsten rod, and produced from pure tungsten plate, tungsten sheet and pure tungsten rod according to relevant technology, many types of preparation methods are available. It has wide application in rare earth smelting, quartz glass, crystal growth and other industries, and plays an important role in modern industry.

There are many factors, which can influence the welding effort of resistance welding, which is applied tungsten copper as electrodes, such as welding current, time, pressure, electrode shape and properties and workpiece surface condition.

There are four types of resistance welding, which can use tungsten copper bonded copper electrode as welding tip, spot welding, seam welding, butt welding and projection welding.

In the conventional method to produce WC–Co material, tungsten powder is obtained from the reduction of tungsten oxides or ammonium paratungstate (APT) followed by a carburization step to obtain tungsten carbide powder. Generally, the particle size of WC–Co powder is on the micron scale. Recently, solution chemical synthesis methods such as spray conversion process and chemical co-precipitation have received increased attention for the production of nanostructured WC–Co material in order to improve the properties of sintered WC–Co materials.

Tungsten is one of the most highly refractory metals and is well applied in lamp filaments, heating elements in high temperature furnaces, electronic heaters, X-ray emission tubes, TIG welding electrodes etc. The widely applications of tungsten result from its thermal resistance to high temperature, high hardness, and high wear resistance.

Tungsten, owing to its high melting point combined with high strength at elevated temperatures, high thermal conductivity and low sputtering yield, is being considered as one of most promising candidates for plasma facing wall material in future fusion reactors.

It is known that preparation of tungsten carbide mainly consists of the following steps. Ammonium paratungstate (APT) is produced from ammonium tungstate solution through evaporation and crystallization, and then tungsten trioxide is produced by calcining APT, finally, tungsten carbide is prepared by hydrogen reduction and followed carbonization. Studies have showed a smaller particle size and uniform distribution of APT has a positive effect on the physical properties of tungsten carbide such as hardness, heat resistance, and wear resistance.

There are three types of tungsten wire application property: high temperature, room temperature and wire diameter consistency.  

The doped tungsten wire is the wire that dopes certain amount of potassium and silicon into pure tungsten powder. It will not only increase the color temperature, luminous efficiency and life time of wire, but also has well anti sag propery, it can be used as special lamp filament with high working temperature such as halogen lamp. Provided that some alloy elements such as cobalt are added into the doped wire, the wire will have high strength and shock resistance. The wire is generally used in lighting system in vibration environment, lamps for various vehicles (motorcycles, automobiles, trains, airplanes, etc) as well as special light bulbs for military purposes, heating wires for aeroengine, etc.