Welding is a manufacturing process that is usually used to join two metal parts together. This process is done by melting the two workpieces and adding filler material. When this molten material cools down, it becomes a strong joint. Different energy sources can be used, but the most common one is the electric arc. An electric current is passed through an electrode and creates an arc when it is close to the base material. This arc is created because of the differences between the electrode and the base material. This arc generates heat and melts the material. Arc welding is the most common type of welding used by manufacturers because it can be manual, semi-automatic or even, fully automated.
Two kinds of electrodes can be used in arc welding. They can be consumable or non-consumable. Let’s take a look at the different welding methods using these kinds of electrodes.
The consumable electrode will act as both the filler material and the electrode during the weld, so no supplementary material is needed. There are 4 common types of welding that use these electrodes.
Shielded Metal Arc Welding (SMAW)
This welding method is also known as Manual Metal Arc Welding (MMAW) and it is one of the most common types of arc welding. The consumable rod is often covered by a flux that creates vapor when it is melted. This gas will protect the weld from external contamination. Moreover, the flux will cover the weld with a layer of slag. This slag must be removed afterwards. Even if this welding type is simple, requires little training and inexpensive equipment, it is still a slow process, because the electrode has to be replace frequently and the slag removed. Also, different electrodes are needed to weld different materials. This method is often used for construction.
Gas Metal Arc Welding (GMAW)
Also known as Metal/Inert-Gas (MIG), this welding method is a semi-automatic or automatic process. The electrode still acts as filler material and it is fed continuously through the welding gun. Since this electrode does not have flux around it, an inert or semi-inert gas is sprayed around the wire to protect the welding environment. This method offers high welding speed, but requires more complicated equipment. Because of its versatility, quality and speed, it is often used in the automotive industry.
Flux-cored Arc Welding (FCAW)
This welding type is similar to shielded metal arc welding, but the flux is located inside the consumable electrode. It is also often used for construction.
Submerged Arc Welding (SAW)
With this method of welding, the flux is in a granular form that covers the joint being welded. So that the electrode produces an arc underneath the flux. This process produces high quality welds since the flux protects it from contaminants. The slag usually comes off by itself. Since the arc can not be seen, this process is typically automated.
This kind of welding generally needs a separate filler material.
Gas Tungsten Arc Welding (GTAW)
This manual welding method is also known as Tungsten/Inert-Gas (TIG). The electrode is made out of tungsten and an inert or semi-inert gas is needed. Moreover, a filler material is also needed since the electrode is non-consumable. It creates a stable arc and produces high quality welds. However, this technique needs significant operator skill and is relatively slow. It is the preferred method when it comes to thin materials, light metals and stainless steel.
Spot welding is a very common process in the automotive industry. It generally consist of two copper alloy electrodes that are located on each side of the parts to weld. A strong current passes through the two layers of material, from one electrode to the other and melts the zone between them. This creates a spot that firmly joins the two parts.
In conclusion, each welding process has their pros and cons, but you will always be able to find the required method for your welding needs. Moreover, since welding is a very common manufacturing process, automation is a great solution to make high quality and consistent welds, even though not all welding methods can be used for automation. Robotic welding will soon be discussed in another article, so stay tuned to our blog.
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