What is Tungsten Electrodes? Explain in details different types of Tungsten Electrodes with examples.
Tungsten electrodes are a type of non-consumable electrode used in tungsten inert gas (TIG) welding and plasma arc welding. Tungsten is a refractory metal known for its high melting point, excellent heat resistance, and low thermal expansion. Tungsten electrodes are used to create an electric arc that generates the heat necessary to melt and join metals without being consumed during the welding process.
Different types of tungsten electrodes are available, each with specific properties and applications. Here are some common types:
- Pure Tungsten (WP): Pure tungsten electrodes, designated as WP, are made of 99.5% pure tungsten. They have a green color code and are primarily used for welding aluminum and magnesium alloys. Pure tungsten electrodes have excellent arc stability, low burn-off rate, and good resistance to contamination. However, they have a lower current-carrying capacity compared to alloyed tungsten electrodes.
- Thoriated Tungsten (WT/WTh): Thoriated tungsten electrodes, designated as WT or WTh, are alloyed with a small percentage of thorium oxide. They have a red color code and are commonly used for both AC and DC welding applications. Thoriated tungsten electrodes offer high current-carrying capacity, good arc stability, and excellent resistance to thermal shock. They are widely used for welding carbon steel, stainless steel, nickel alloys, and titanium. However, due to thorium’s radioactive properties, thoriated tungsten electrodes have safety concerns and are being phased out in some regions.
- Ceriated Tungsten (WC/WCe): Ceriated tungsten electrodes, designated as WC or WCe, are alloyed with cerium oxide. They have a gray color code and are suitable for both AC and DC welding applications. Ceriated tungsten electrodes offer good arc stability, easy starting, and excellent re-ignition properties. They are commonly used for welding carbon steel, stainless steel, nickel alloys, and titanium. Ceriated tungsten electrodes are considered a safer alternative to thoriated electrodes due to their lower radioactivity.
- Lanthanated Tungsten (WL/WLa): Lanthanated tungsten electrodes, designated as WL or WLa, are alloyed with lanthanum oxide. They have a gold color code and are suitable for both AC and DC welding applications. Lanthanated tungsten electrodes offer good arc stability, easy starting, and long service life. They provide reliable performance across various welding currents and are commonly used for welding carbon steel, stainless steel, nickel alloys, and titanium. Lanthanated tungsten electrodes are considered a safe and popular alternative to thoriated electrodes.
- Zirconiated Tungsten (WZr/WZr): Zirconiated tungsten electrodes, designated as WZr or WZr, are alloyed with zirconium oxide. They have a brown color code and are primarily used for AC welding applications. Zirconiated tungsten electrodes offer good resistance to contamination, excellent heat resistance, and stable arc characteristics. They are commonly used for welding aluminum and magnesium alloys, as well as for other AC applications.
It’s important to choose the appropriate tungsten electrode based on the specific welding application, the type of base metal, the welding current, and the desired properties of the weld joint. The diameter of the tungsten electrode is also important and should be selected based on the welding current and the thickness of the material being welded. Consulting the electrode manufacturer’s guidelines and considering the specific welding parameters is crucial for achieving high-quality TIG welds.