Tungsten sheet gold

Refractory metals : tungsten&moly tungsten bar is a refractory metal . And

generally have a melting point above 1650 ℃ some reserves of

zirconium metal and the melting point higher than the melting

point (1852 ℃) is called a metal refractory metal . Typical

insoluble metal tungsten, tantalum, molybdenum, niobium,

hafnium , chromium , vanadium , zirconium and titanium . As a

refractory metal , tungsten carbide ball is the most important advantage

of a good high temperature strength , and the molten alkali

metal vapor with good corrosion resistance , only above 1000

℃ tungsten carbide rod oxide appeared before the volatile liquid oxides.

However , it also has a plasticity - brittle transition

temperature is high at room temperature, the plastic working

is difficult disadvantages . tungsten carbide rods as the representative

of refractory metals in the metallurgical , chemical,

electronics , lighting , industrial machinery and other

sectors has been widely used .
Rare : Tungsten is a rare metal . Usually refers rare in

nature or distribution of the content is less scattered metal

. Tungsten is an element of a broader distribution of various

types of rocks found in almost all over , but at low levels .

Tungsten content in the crust of 0.001 % in the average

content of granite 1.5 × 10-6, this characteristic led to

its extraction very difficult, often isolated extract only

exchange with organic solvent extraction and ion . With the

development of science and technology progress and

metallurgical processes, equipment and analytical techniques

, and expanding the production scale of rare metals such

purity tungsten continuous improvement , performance

continued to improve, increasing variety , thus expanding the

applications of tungsten . China's abundant mineral resources

of tungsten and tungsten production in total exports account

for the world.