Why is pure tungsten rarely used in argon tungsten arc welding?
Tungsten plate argon soldering (TIG) is gas shielded welding with a tungsten needle as one pole of an arc.As a non-melting electrode, tungsten electrode has high melting point, less volatile and high strength at high temperature. Tungsten has a melting point of 3690K, a boiling point of 5900K and a high red-heat intensity. 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), lanthanum tungsten (W-La), etc., which are widely used in the market, have better current carrying capacity, arc starting performance and service life than pure tungsten. It is mainly because their escape work is lower than pure tungsten, so that they have ① high durability, long life, so that the burn loss rate is reduced, the number of tungsten electrode grinding is reduced.② The allowable current is large and the current carrying capacity is enhanced.(3) good technology, tungsten electrode electron emission ability is strong, reliable arc, arc stability, low no-load current.
It is worth noting that ① thorium and tungsten contain trace amount of thorium is a radioactive element, harmful to health, try to use cerium tungsten, lanthanum tungsten instead.② pure tungsten is a good choice when welding aluminum.
In short, pure tungsten is rarely used in practical applications due to the above reasons.
