In high-precision welding processes such as tungsten inert gas welding (TIG) and plasma welding, the cleanliness and anti-contamination ability of the electrode has a direct impact on the arc quality, weld consistency and equipment stability.
Once the electrode is contaminated, such as contamination with welding metal, oxides or impurities, it will not only cause arc instability and difficulty in starting the arc, but may also cause welding defects and even equipment damage. Therefore, choosing an electrode material with good anti-contamination ability is crucial to improving the reliability of the welding process.
As one of the most widely used non-radioactive tungsten-based materials, lanthanum tungsten electrode not only has good arc starting performance, long life, and high thermal stability, but also has excellent anti-pollution capabilities, making them a reliable choice in various welding scenarios.
1. The core of anti-pollution comes from the stability of material structure
Lanthanide tungsten electrodes are made by sintering high-purity tungsten powder with 1.0 % to 2.0% lanthanum oxide (La?O?). Lanthanum oxide is distributed at the tungsten grain boundaries, contributing to grain refinement, structural stability, and ablation resistance under high-temperature welding conditions. This structure not only improves thermal stability but also reduces the electrode's tendency to adsorb and react with external metallic elements. Even when exposed to molten droplets of materials such as copper, aluminum, and nickel during welding, the tip of the lanthanum- doped electrode is less susceptible to adhesion, melting, or chemical reactions.
In contrast, traditional pure tungsten electrodes or materials with lower melting points and looser structures are more susceptible to contamination. Once the tip contacts the molten pool, impurities can quickly adhere to the electrode surface, leading to unstable ignition, arc deviation, and even black spots and spatter.
2. More stable performance in responding to pollution
In actual use, lanthanide tungsten electrodes show good self-cleaning ability. When the welding process is briefly contaminated (such as fluctuations in the flow of protective gas, the tip contacting the molten pool, etc.), by appropriately increasing the current or adjusting the electrode angle, the contaminated layer can be quickly "burned off" and restored to normal working state. This self-recovery ability is particularly suitable for complex position welding, intermittent welding or automated equipment that requires frequent arc starting.
At the same time, this type of electrode has a low adhesion to oxides and residues. Even if there is slight contamination on the surface of the electrode tip, it will not seriously affect the electron emission efficiency and arc stability, which is conducive to ensuring the efficiency and quality of continuous operation.
3. Use habits to further enhance anti-pollution effects
Although lanthanum tungsten products have excellent anti-pollution performance, good operating habits are still the key to extending their service life in daily welding practice:
Maintain argon purity and stable flow: prevent air from mixing in and causing oxidation;
Correctly polish the electrode tip: avoid cracks or grooves and reduce points for contamination to attach;
Avoid excessive contact of the electrode with the molten pool: reduce the chance of contamination by molten metal;
Check and clean the electrodes regularly: if any abnormal color or arc drift is found, they should be polished or replaced in time.
4. Suitable for occasions with high cleanliness requirements
Due to its excellent anti-pollution ability and non-radioactive properties, lanthanum tungsten electrodes are widely used in industries with strict control of metal impurities, such as medical device manufacturing, aerospace, electronic component welding, and food equipment manufacturing. In these high-standard occasions, even in the face of continuous production or high-precision welding tasks, they can maintain stable performance and avoid quality risks caused by electrode contamination.
