Using pure tungsten or activated tungsten (thorium tungsten, cerium tungsten, zirconium tungsten, lanthanum tungsten) as inert gas shielded arc welding of non melting electrode. The metal is melted by the arc between the tungsten electrode and the workpiece to form a weld. Tungsten electrode is not melted in the welding process, only plays the role of the electrode. At the same time, the nozzle of the welding torch sends argon or helium into electrode for protection, and other metals can be added as needed. (It is commonly referred to as TIG welding in the world, Tungsten Inert Gas is abbreviated TIG.) Its literal translation is Tungsten inert gas welding, which is commonly known as non melting gas shielded welding. Whether manual welding or automatic welding 0.5 ~ 4.0mm thick stainless steel, the most commonly used is TIG welding. TIG welding is also used for the welding of thick section. TIG welding heat source is DC arc, the working voltage is 10 to 15 volts, but the current can reach up to 300 ampere, the workpiece can be as a positive electrode, the tungsten electrode in the torch can be as a negative electrode. Inert gases are generally argon.
 
Several common electrodes:
Cerium tungsten electrode: non radioactive material. The electron emission ability is higher than the thorium tungsten, the arc voltage is low, the arc is stable. When the cathode is positive, the allowable current density is 5%-8% higher than that of the thorium tungsten, the AC current density is high, the service life is long, and the utility model is suitable for the direct current or alternating current welding, and the use time is longer than that of the thorium tungsten in the same amount. It is usually used for the welding of carbon steel, stainless steel, titanium and other metals.
 
Thoriated tungsten electrode: Now the most commonly used tungsten electrode products have arc easy, stable arc, long electrode life, good anti pollution characteristics, which is usually used for direct current, welding carbon steel, stainless steel, nickel and titanium and other metals.
 
Lanthanum tungsten electrode: the performance is great in the AC welding. At the same time, because the end of the electrode in the welding process is spherical, and has strong anti pollution ability, which is very suitable for the welding seam.
 
Zirconium tungsten electrode: In the alternating current environment, the welding performance is good, especially in the case of high load current, it shows the superior performance, which is the other electrode can not be replaced. In the welding, the end of the zirconium tungsten electrode can be kept in a round shape, which can reduce the phenomenon of tungstenizing and it has good corrosion resistance.
 
Pure tungsten electrode: Tungsten content is greater than or equal to 99.5%, it has excellent performance in AC welding. It can also be used for direct current welding, but it is not as good as cerium tungsten and thorium tungsten. It is usually applied to the welding of aluminum and magnesium (in the case of current generation).
 
Yttrium tungsten and composite electrode: In the process of welding, the arc beam of yttrium tungsten electrode is long and slender, and the degree of compression is large. It is used in military industry and aerospace industry. The composite multielement tungsten electrode is that adding two or more rare earth oxides in the tungsten base, and various additives are complementary to each other to supplement each other.