MIG Welding
MIG Welding: The Most Renowned Welding Technique
If you need reliability in welding, choose MIG welding!
MIG, or Metal Inert Gas welding, is called Gas Metal Arc Welding or GMAW in the American Welding Society. For some, it is also known as wire welding. MIG welding is a popular way to join two or more metals using a constantly fed wire electrode. This wire melts along with the metal during the welding process, which creates a strong bond. A gas is produced to prevent the molten metal from being contaminated, which assembles a clean and high-quality weld.
MIG welding is fast, versatile, relatively simple, and easy to understand and comprehend when compared to other welding techniques. MIG welding is often used in industries because of how versatile it is and how easy it is to use. Not only that, but you can use any metal with a different thickness’ and MIG welding will do the work. This is why when it comes to working with automotive, construction, or manufacturing applications, the safest option is to use the MIG welding technique.
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How it Works
MIG welding works by producing an electrical arc between a metal wire electrode and the parts that you are welding by heating it at a very high temperature. This melts the base metal, allowing it to join together. A thin wire acts as the electrode.
A spool mounts on a gun or inside the welding machine, which feeds the wire, which is a similar material. That spool then comes out through the nozzle of the welding gun.
When the welding trigger is pulled, the wire is fed continuously. As this trigger is pulled, the welding current and the shielding gas are switched on. An electric arc forms between the wires and the workpiece and heats both metals above their melting points.
These metals mix or coalesce, solidify, and join the workpieces into a single piece. The joining metal in these parts is called the base metal. The metal that comes out of the metal wire electrode is called the filler metal. Which means that it adds filler metal to the joint. Because the wire electrode melts as it is being used, it is called a consumable electrode process.
The MIG wire goes through the wire feeder and into a flexible tube or conduit liner. The liner is pushed through the hose or welding lead toward the torch nozzle. The contact tip feeds the nozzle wire, which comes out at the point of the weld.
Welding lead also feeds the shielding gas. It goes through a gas diffuser and flows out through the nozzle. The shielding gas, often made from a mix of argon or CO2, is used to prevent the reaction of the molten metal with oxygen, water vapors, and other atmospheric things. To ensure that the arc function is accurate, the gas is really important.
What Can Gas Metal Arc Welding (GMAW) be Used on
If you are looking for a welding technique that is best for a broad range of applications across various industries, then MIG welding is your best option because it is highly versatile. MIG welding excels at joining various types of steel. That means that you can weld mild steel and stainless steel without a doubt. But its most common use is fabricating building components, repairing car frames, and creating furniture or lighting fixtures.
When we look at the industries where the MIG welding technique is used, the automotive and aerospace industries are also included. And for them, aluminum is often the material that is used. MIG welding can also be used to weld copper, however it is more difficult. We recommend using a TIG machine for this.
Pros vs Cons Overview
- Easy to Learn
- Ability to Weld Thin Materials
- Fast Welding Process
- Higher Weld Quality
- Equipment Cost
- Shielding Gas Required
- Limited to Indoor Use
- Not Ideal for Dirty Materials
Pros of MIG Welding
There are a lot of advantages when it comes to using the MIG welding technique, which is why it is often preferred. For one, it doesn’t need the user to pause continuously and change the electrodes, which automatically increases production rates and makes this technique quicker when welding.
MIG welding produces minimal slag compared to other techniques, which reduces its cleaning time and effort.
If you’re a beginner, then MIG welding gives you a straightforward set-up and operation as compared to other arc welding techniques. The constant feeding of the wire and the open arc results in clear visibility of the weld pool. This allows you to control the weld quality.
If you want to weld steel, aluminum, stainless steel, or any other metal, MIG welding can give you a clean, strong, and aesthetically pleasing result if used properly. This is why MIG welding is a highly chosen welding technique for direct application.
Not only that, but the constant wire feed allows for quicker speeds compared to alternate arc welding processes available in the market. The improved and increased productivity and the minimal post-weld cleaning often make MIG welding cost-effective in the long run, which is something an inspiring welding startup should look to achieve.
Cons of MIG Welding
While MIG welding has many advantages under its belt, it also has some limitations that you need to consider. MIG welding setups typically involve a welding machine, gas cylinder(s), hoses, regulators, and consumables like wire electrodes. This can lead to higher initial startup costs compared to more straightforward arc welding methods, like stick welding.
MIG welding needs to have continuous wire feeding, shielding gas agents, and the occasional replacement of nozzles and contact tips, which only adds up to the operational costs of MIG welding.
The hardest part is setting the wire speed and voltage on your machine, which may require a few test welds and a little practice to dial in. Some higher-budget machines can do this automatically.
MIG welding equipment, such as gas cylinders, is less portable than the other available methods. Due to this, it’s not a suitable solution for outdoor work or scenarios where movement is continuous.
Shielding gas can be easily disrupted by the wind, which can compromise the weld quality, which in turn makes it less ideal for outdoor welding in windy conditions. MIG welding is the ideal choice when welding thin to medium-thickness metals. However, it should be noted that it may not be the right choice for very thick materials due to the limitations of heat penetration and the potential for burn-through.
The fluidity of the molten metal pool in MIG welding makes it hard for vertical or overhead welding positions when compared to other techniques. MIG welding often requires more surface preparation, which means you should ensure cleanliness and proper fit-up of the metal pieces. Like any arc welding process, MIG welding involves high heat, sparks, and fumes. It requires adequate safety precautions and personal protective equipment, which, if not followed, can lead to Worker Safety Laws.
Shielding Gas & Gasless Flux
MIG welding uses shielding gas to cover the molten metal as it’s deposited before it solidifies and fills the weld puddle. The reason the gas is needed when you are welding is to protect the weld from the effects of any air contamination, which could make it less robust and more fragile. The most common choice is pure argon when welding non-ferrous metals, and it creates a low-clearance arc for a tidy, spatter-free weld. Argon/CO2 mix is an ideal gas blend for many different types of steel as it keeps the arc stable and the welds high. However, it should be noted that various metals will need different gas mixes.
You can rent a bottle and purchase the gas from many welding suppliers. You must always remember, that choosing a suitable gas is crucial for achieving high-quality MIG welds. Another option is to use gasless flux core wire, which generates gas from the flux as you weld. The downside is that flux core is only suitable for carbon steel, and getting a clean and tidy-looking weld will be more challenging.