Why is pure tungsten rarely used in TIG welding?
Argon arc welding (TIG) of tungsten plate is gas shielded welding with tungsten needle as one electrode of arc. Tungsten electrode, as an immiscible electrode, requires high melting point, less volatilization at high temperature and high strength at high temperature! The melting point of tungsten is 3690k, its boiling point is 5900k, and its red heat intensity is high. It is an ideal non melting electrode material.
Thorium tungsten (W-Th), cerium tungsten (W-Ce), zirconium tungsten (W-Zr), cesium tungsten (W-Cs), barium tungsten (W-Ba) and lanthanum tungsten (W-La) are widely used in the market. Their current carrying capacity, arc striking performance and service life are better than those of pure tungsten. The main reason is that their escape work is lower than that of pure tungsten, ①so that they have high durability, long service life, lower burning loss rate and wear times of tungsten electrode The number decreased. ② The allowable current is large and the current carrying capacity is enhanced. ③ It has good processability, strong electron emission ability of tungsten electrode, reliable arc starting, stable arc and low no-load voltage.
It should be noted that there are ①trace thorium in thorium and tungsten, which is a radioactive element, which is harmful to human health. Cerium tungsten and lanthanum tungsten should be used instead. ② Pure tungsten is a good choice when welding aluminum.
In short, due to the above reasons, pure tungsten is rarely used in practical application.
