Based on the main oxide that is utilised and how much of the entire electrode mass it makes up, tungsten electrodes are categorised according to their chemical compositions. To make things easier, each distinct tungsten electrod has been given a unique code and colour. When welding with alternating current (AC), pure offer exceptional stability; however, they can also be utilised with direct current (DC) and argon or helium shielding gas. They are often less expensive, have a smaller current carrying capability, and are less resistant to contamination from welds. Due to its ability to keep a neat, balled end, EWP electrodes are typically employed to weld magnesium and aluminium. They are often utilised in less important applications, nevertheless, where a small amount of tungsten contamination in the weld pool is acceptable. When plasma welding or using the arc welding technique known as tungsten inert gas (TIG), tungsten electrodes are employed. An inert gas is used in both procedures to shield the electrode, arc, and weld pool from ambient pollution.
These non-consumable electrodes are made of either pure tungsten or an alloy of tungsten and other rare-earth elements and oxides, and they are available in a variety of diameters and lengths. Depending on the base material type, thickness, and whether you’re using alternating current (AC) or direct current to weld, you can choose an electrode for GTAW (DC). The three end preparations—balled, pointed, or truncated—must be chosen carefully if you want to achieve the best results and avoid contamination and rework. Each electrode is color-coded to make it clear what type it is. At the electrode’s tip, the colour is visible.
The maximum consumption rate of any electrode is achieved by pure tungsten electrodes (AWS classification EWP), which are often less expensive than their alloyed counterparts. They also contain 99.50 percent tungsten.
When heated, these electrodes produce a tidy, balled tip and offer excellent arc stability for AC welding with a balanced wave. For AC sine wave welding, pure tungsten also offers good arc stability, particularly when welding aluminium and magnesium. Due to the fact that it cannot produce the powerful arc beginnings associated with thoriated or ceriated electrodes, it is not frequently utilised for DC welding.AWS classification EWG rare-earth tungsten electrodes may contain unspecified rare-earth oxide additions or hybrid mixtures of various oxides, but producers are required to list each additive and its percentage on the packaging. Desired outcomes can include a stable arc in both AC and DC processes, longer lifetime than thoriated tungsten, the ability to use a smaller-diameter electrode for the same job, use of a higher current for a similar-sized electrode, and less tungsten spitting. These outcomes can vary depending on the additives.
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