The main differences between thoriated tungsten electrode and lanthanum tungsten electrode are as follows:
1. Different ingredients
Thorium tungsten electrode: The main ingredients are tungsten (W) and thorium oxide (ThO₂). The content of thorium oxide is usually between 1.0%-4.0%. As a radioactive substance, the radioactivity of thorium oxide can improve the electron emission ability to a certain extent.
Lanthanum tungsten electrode: It is mainly composed of tungsten (W) and lanthanum oxide (La₂O₃). The content of lanthanum oxide is about 1.3% - 2.0%. It is a rare earth oxide and is not radioactive.
2. Performance characteristics：
Electron emission performance
Thorium tungsten electrode: Due to the radioactive decay of thorium element, some free electrons will be generated on the surface of the electrode. These electrons help to reduce the work function of the electrode, thereby making the electron emission ability stronger. It can also emit electrons more stably at lower temperatures, which makes it perform better in some occasions such as AC welding where frequent arc initiation is required.
Lanthanum tungsten electrode: The electron emission performance is also relatively good. Although there is no radioactive auxiliary electron emission, lanthanum oxide can refine the grain structure of tungsten and keep the electrode at a good electron emission stability at high temperature. In the DC welding process, it can provide a stable arc and make the welding quality more uniform.
Burning resistance
Thorium tungsten electrode: In a high temperature environment, due to the presence of thorium oxide, the electrode's burn resistance can be improved to a certain extent. However, with the increase of use time and the increase of welding current, the electrode head will still burn to a certain extent.
Lanthanum tungsten electrode: It has good burn resistance. Lanthanum oxide can form a protective film on the electrode surface at high temperature to prevent further oxidation and burning of tungsten. During high current welding or long-term welding operations, the end shape of the lanthanum tungsten electrode can remain relatively stable, reducing the number of frequent electrode replacements.
Arc starting performance
Thorium tungsten electrode: It is relatively easy to start the arc, because its lower work function allows a conductive channel to be established between the electrode and the weldment relatively quickly during the arc starting stage, and the arc can be ignited relatively smoothly.
Lanthanum tungsten electrode: The arc starting performance is slightly inferior to that of thorium tungsten electrode, but under the appropriate welding equipment parameter settings, it can still achieve a good arc starting effect. And it performs well in arc stability after arc starting.
3. Application scenarios
Thorium tungsten electrode
Because of its good electron emission performance and arc starting performance, it is often used in AC argon arc welding, especially when welding aluminum, magnesium and its alloys and other materials with high arc starting requirements. However, due to the presence of radioactivity, its use is restricted in some occasions with strict radiation protection requirements, such as medical equipment manufacturing, food industry equipment welding and other fields.
Lanthanum tungsten electrode
Because there is no radioactive hazard, its application range is wider. It can be used in DC argon arc welding and some AC argon arc welding scenarios. When welding materials such as stainless steel, carbon steel, copper alloy, etc., it can exert its stable arc performance and good burning resistance to ensure welding quality.
4. Safety
Thorium tungsten electrode: Because it contains thorium oxide, a radioactive substance, it will produce certain radioactive hazards during use. If exposed for a long time, it may have adverse effects on the health of operators, including increasing the risk of diseases such as cancer. Therefore, when using thoriated tungsten electrodes, strict radiation protection measures need to be taken, such as wearing protective clothing and using radiation monitoring equipment.
Lanthanum tungsten electrodes: do not contain radioactive substances, are relatively safe, and do not need to worry about radioactive contamination during use, meeting environmental protection and health and safety requirements.
Post time: Dec-19-2024