What is the difference between argon arc tungsten electrode wt 20 and wc20 wp
Thorium tungsten electrodes contain thorium oxide (Th02 or thorium oxide), which is the most commonly used tungsten electrode in the United States and has become a standard for judging the quality of other tungsten electrodes. However, due to the low-level radioactive hazards of this tungsten electrode, many users have switched to other options. In general, a 2% thorium tungsten electrode is a better tungsten electrode, with the lowest electron work function, and it performs well even under overload voltage. The performance of thorium tungsten electrode is better than pure tungsten electrode in many aspects. Thorium oxide provides a current-carrying capacity that is about 20% higher than that of pure tungsten, generally has a longer service life, and helps prevent pollution during welding. Using thorium tungsten electrodes, arc starting is easier, and the arc is more stable than pure tungsten electrodes or zirconium tungsten electrodes. Both thorium tungsten electrode 1% (EWTh – 1) and thorium tungsten electrode 2% (EWTh – 2) can be used for DCEN. They keep the tip sharpened during the welding process, which can be used to weld steel pipes, usually without direct current, because it is difficult to keep the tip of the welding ball without cracking, which is necessary for direct current.
Cerium tungsten electrode (EWCe-2 orange stripes)
Cerium tungsten electrode was introduced to the United States in the early 1980s as a non-radioactive tungsten electrode to replace thorium tungsten. Usually the cerium tungsten electrode contains 2% cerium oxide, which is currently common. As we all know, cerium tungsten electrode is suitable for DC welding at low voltage, because it is easy to start arc at low voltage, and it is 10% lower than thorium tungsten at work. For pipeline welding, cerium tungsten electrode is the most popular, and it is also commonly used to weld small parts. Compared with pure tungsten electrode, cerium tungsten electrode has lower burning rate or evaporation rate. As the content of cerium oxide increases, these advantages also increase. Cerium has the highest mobility, so at the beginning of welding, the welding performance is very good. Over time, as the grains grow, the mobility will decrease significantly. However, under low voltage, the lifetime is longer than thorium tungsten electrode. It is because of these characteristics that it is usually beneficial to short-cycle welding or specific welding volume before the electrode can be replaced. It is best to use thorium tungsten electrode or lanthanum tungsten electrode for high current and voltage welding. Cerium tungsten electrode (EWCe-2) is successfully used for DC or AC, but it is mainly used for DC welding because it is easy to split during AC welding.
Pure tungsten electrode (EWP: green stripes)
The pure tungsten electrode contains a minimum of 99.5% tungsten and no alloying elements. Pure tungsten has a very high electron work function. Therefore, compared with other alloy tungsten electrodes, pure tungsten electrodes are more difficult to start and maintain the stability of the arc beam. In addition, due to the high electron work function, the temperature of the electrode tip is high and the grain growth is prone to occur, which will cause the arc beam to be unstable, the arc starting is more difficult, and the service life is shorter. Pure tungsten is only used for AC welding, however, a good DC can also be selected.
