A weld is a useful and practical machine tool that has been around for many decades in one form or another. In our last blog, we spoke about what welding is and some interesting facts about the art. Today, we’re going to have a look at some of the welding techniques that are used in the industry and what makes them so unique.
Metal inert gas welding (MIG) or gas metal arc welding (GMAW)
Considered one of the easier types and common introductory technique for beginners, metal inert gas welding (MIG) – also known as gas metal arc welding (GMAW) – is suited for welding stainless-steel, mild steel and aluminium.
The process is fairly simple – a wire that is being constantly charged by an electrode current is fed through your weld to the two pieces of metal you wish to fuse. A shielded gas then runs along the wire to heat up the two metals, fusing them into one.
Shielded metal arc welding (SMAW)
This technique is a very basic and common technique. Whilst it is still considered a little trickier than MIG welding, it is a much smaller welding machine and can be picked up for use in a home environment – provided the proper precautions and safety measures are taken.
SMAW is alternatively known as stick welding. The stick uses electric current to form an electric arc that joins the two pieces of metal together. This technique is great for welding iron and steel sheet metal together, as well as general repair, construction and manufacturing purposes.
Tungsten inert gas (TIG) or Gas tungsten arc welding (GTAW)
Sometimes referred to as micro or precision welding, tungsten inert gas (TIG) is the process of melting the base sheet metal using the welding machine, and then fusing it together with the second piece of metal. This is done by superheating a very precise area using a tungsten electrode.
Most common metals can be welded together using this technique, but it is worth noting that this is probably the most difficult and time-consuming technique. This is a fairly new technique and is used for small-scale tasks predominantly. One of the notable features of this technique is that because it is so precise it usually does not require any extra clean-up –such as sanding – because it is not meant to leave any mess or residue.
Plasma arc welding (PAW)
Just like TIG, Plasma arc welding utilises a tungsten electrode, which is held inside the nozzle and acts as a constrictor. Plasma gas is then ionised within the nozzle and – due to the constrictions from the electrode – exits the nozzle at high speeds. Plasma arc welding has a high heat input, meaning the affected weld zone is quite wide – which may be considered an advantage or disadvantage depending on what you’re going for.
Electron beam welding (EBW)
This technique is quite a bit different from the more traditional ones we’ve been looking at. A high-speed stream of highly focused electrons from the welding machine bombards the sheet metal and superheats it via kinetic energy, allowing you to fuse the two desired pieces together.
This ultra-high energy beam allows for both a widely affected area as well as a small one for great precision. A vacuum setup is required to remove any possible gas related contaminations as well as to control the diameter and flow of the electron beams accurately.
Laser beam welding (LBW)
LBW is a very fast technique where the base metal is continuously blasted by a focused beam of photons. Because the concentrated photon beam can bring the sheet metal to its liquid state rapidly, the beam itself does not need to be sustained for very long and also has a smaller affected zone.
There are a few different output methods that LBW uses such as continuous waves and pulsing waves. The continuous wave – as mentioned before – can heat sheet metal very quickly and therefore doesn’t need to be used for very long. The pulsing wave does take a little longer but allow the metal to cool in between pulses – which can be useful if you’re fusing together a heat-sensitive metal.
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