Ultrafine tungsten powder is the important raw material for producing fine grain cemented carbide, the raw materials for producing superfine tungsten powder consist purple tungsten oxide(purple tungsten) and blue tungsten oxide(blue tungsten). Blue tungsten oxide is most widely used raw material to produce tungsten powder by hydrogen reduction method. As long as the conditions are low temperature, dry hydrogen, high hydrogen flow and thin material layer, ultrafine tungsten powder is able to be produced by hydrogen reduction method. However, too high hydrogen flow and thin material layer will increase the cost. Purple tungsten oxide is a type of tungsten oxide product developed in recent years. It has unique properties and many advantages in the production of ultra-fine tungsten powder. Many metallurgical experts do wide range of research on it. Producing fine and uniform superfine tungsten powder is the key to producing superfine grain cemented carbide. 

The testing method of sag of tungsten wire is processed according to Chinese standard of GB 4105-83, which is suitable for the diameter of Ø0.35~1mm.

The following is the technical specifications of tungsten contact for breaker, including range, standard, technical specification, testing method, transportation, packing, etc.

Urine is one of the most gravimetric nitrogen (N) carriers in human excrement and contributes 80% of the nitrogen and 10% of the COD load in urban sewage in spite of accounting for only one percent of domestic wastewater.