The Difference Between the Different Types of Welding Electrodes
Welders have to make important buying decisions every time they purchase new equipment and consumables, as each and every choice they make will greatly impact their welds. While beginners typically need to consider just a couple of basic factors, more experienced welders need to understand the more in-depth aspects of their gear. Take electrodes, for example. There are a couple of different types, all of which have their own strengths, uses and weaknesses. Picking the right electrode will have a huge impact on the quality and the strength of your welds.
But with so many different types of welding electrodes, how do you pick the right one? Well, if you’re a beginner, you need to know what the electrode is, and what it does. It’s basically a piece of wire that’s connected to the welder. A current is fed through the electrode, and that’s how two metal pieces are joined firmly together. In the case of stick and SMAW welders, the electrode melts and becomes a part of the weld. These electrodes are referred to as consumable electrodes. TIG welding electrodes, on the other hand, don’t melt, and are called, you guessed it, non-consumable electrodes. Regardless, there are many different types and variations within these two groups, which I’ll talk about shortly.
Welding electrodes are typically coated, and the material they’re coated with can greatly vary. Bare electrodes (electrodes without coating) also exist, although they’re usually used for specific welding tasks, like welding manganese steel. That being said, picking the right electrode for your welding job is essential for creating strong welds with great bead quality.
As aforementioned, stick welders typically use consumable electrodes, which can be lightly coated and shielded arc or heavy coated. As their name implies, light coated electrodes feature a thin coating that’s been applied by spraying or brushing. The coating is usually made of materials similar to the metals you’re welding. The arc stream created when using bare electrodes can be difficult to manage, so using a light coated electrode significantly increases the arc’s stability. Furthermore, light coated electrodes reduce or completely eliminate impurities like sulfur and oxides, and they allow for neater and smoother welds.
Shielded arc or heavy coated electrodes, on the other hand, are used for welding metals like cast iron. There are three different type of shielded arc coatings – those that contain cellulose, those that contain mineral substances and a combination of the two. The coatings containing cellulose use a layer of gas to shield the weld zone, while the coatings containing minerals leave a layer of slag. The cellulose type is the ideal one as they provide a very effective shielding that results in strong welds.
Non-consumable electrodes include carbon and tungsten electrodes. Carbon electrodes are used in arc welding and they’re made of graphites that can be coated with copper or left bare. Tungsten electrodes, on the other hand, are made from pure tungsten, or tungsten combined with a different percentage of thorium or zirconium. Pure tungsten electrodes are used for lighter applications, while the types containing zirconium and thorium are used for heavy-duty applications as they last longer and are more resistant.