Most of us know that bright, bluish and crackling light that appears during thunderstorms is called lightning. That same bluish light sometimes forms momentarily on the railroad between the pantograph and catenary. It’s called an arc. When it comes to welding, welders use an arc to fuse metals together.
But how does it really work? Without delving too deep into metallurgy, there has to be electric potential between two points to form an arc.
It’s important to understand the basic concept of arc welding, especially if you are planning to become a professional welder. Not everyone realizes that there are various processes of arc welding, and even fewer comprehend the basic principle behind it. To learn more about welding, check out Welding Maniac’s guides. In the meantime, let’s discuss what arc welding is.
What to Know About Arc Welding
Basically, arc welding is one of the many welding processes. It uses an arc that creates intense heat to fuse metal pieces together. The arc is generated continuously by an electric current, which is either AC or DC.
Arc welding is also the simplest and most common form of welding, so you most likely have seen it somewhere, from manufacturing and construction to automotive, aerospace, and many other industries.
How Does Arc Welding Work?
Arc welding has five components: an electrode and electrode cable, ground cable and clamp, metal workpieces, a power supply and an arc.
The arc is created and sustained by the power supply that provides alternating current (AC) or direct current (DC). The electrode is moved through the joint to form the weld.
Now that we know what the components are, it’s time to answer one important question: how hot should a welding arc be in order to melt and fuse metals together?
Well, more or less 6,500 degrees Fahrenheit. Although this does the job of melting and then fusing metal pieces together, high temperatures can also result in molten metals reacting with gasses in the air. This may lead to excessive spatter, porous and weak welds, and low productivity.
These are welding defects, and there are two ways to prevent them from occurring, both of which employ the use of shielding gas. One is to flood the hot weld with a special shielding gas, and the second is to use flux, which generates its own shielding gas and slag when exposed to high temperature. The inert gas and slag work by encapsulating the weld, protecting it from the gasses in the air.
What Are the Types of Arc Welding?
There are four types of arc welding that are commonly used: MIG, TIG, Stick, and Flux-cored welding. They all use an electric arc to weld. Although some people refer to stick welding when they talk about arc welding, it should not be confused with it being the only one. So, one might say, stick welders are arc welders; but not all arc welders are stick welders.
This process is also called Gas Metal Arc Welding. A roll of wire acts as an electrode and is fed to the welding gun. The wire is consumed in the process, and also acts as a filler for the weld. Therefore, the wire alloy is often matched to the type of metal being welded.
TIG welding is sometimes referred to as Gas Tungsten Arc Welding. While MIG uses a consumable electrode which is the wire, TIG makes use of tungsten, a non-consumable electrode to create an arc. The method is ideal for welding aluminum because the arc also serves as a shielding gas that protects the weld from the air, which causes oxidation.
Another name for Stick welding is Shielded Metal Arc Welding. It uses a flux-coated stick as an electrode. With the high heat of the weld, the flux acts as a shield on the molten pool. Similar to MIG, the stick is also consumed in the welding process, and acts as a filler material to the weld.
This arc welding process is similar to MIG welding in that they both use wire as an electrode. However, the core of the wire electrode is filled with flux in this case. In this aspect, flux-cored welding is also similar to stick welding, as they both use flux to create shielding gas and slag that protect the weld. Thus, you don’t have to use external or bottled gas like in MIG welding.
Pros and Cons of Arc Welding
Arc welding actually has more pros compared to other welding processes. The cost of the equipment is relatively low, which should allow you to save more. Additionally, arc welding would require fewer pieces of equipment because of the lack of gas, which should result in even more savings.
Portability is another advantage of arc welding. Most of the materials you would need for the process are easy to carry. Then, there’s versatility, as the process lets you perform on different metals, including dirty metals, in any environment. Not to mention, the resulting welds would be strong and high quality.
As for the cons, you will need proper ventilation to reduce the fumes created by arc welding. While cost is listed as an advantage, it can also be a disadvantage when it comes to metal waste production, as the method tends to produce more waste than others. as it generates more metal waste. Arc welding is also not friendly to thin materials and requires a lot of practice to achieve high-level skill.
We hope this article has provided some helpful insights into the basic concept of arc welding as well as its pros and cons.
Remember, you can choose either AC or DC to generate the arc when welding. Naturally, you must first understand the advantages and disadvantages of each electric current and when to use each to make the best possible decision.