If you are a beginner and want to know the advantages of MIG welding than first you need to understand the basics of the MIG welding process. This article helps you to understand all the basics of MIG welding. After process understanding, you will be able to understand the pros and cons of MIG welding. Controlling of MIG welding process is easy and convenient to use for a beginner. After recognition of MIG welding, you will be able to decide whether the MIG process fulfills your welding requirements or not.
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Applications of MIG Welding
MIG welding is used in the manufacturing industry like the shipbuilding industry, sheet metal industry, pipeline manufacturing industry, automotive manufacturing industry, construction welding, and many others.
About 50% of all weld metal deposition in the industrial sector is through the MIG process.
You can use MIG welding on all thicknesses of metals like carbon steel, stainless steel, aluminum, magnesium, copper, nickel, silicon bronze, and other alloys.
MIG Welding Process
Before you get to know the advantages of MIG welding you need to understand the process of MIG welding. That’s how you understand the advantages better. MIG stands for metal inert gas welding. The American welding society calls this process gas metal arc welding or GMAW. Sometimes it is also called wire welding. In MIG welding, a thin wire not only works as an electrode to the welding area but is also used as a filler metal. This wire is fed from a spool that is mounted inside the welding machine.
The wire is fed continuously by the spool when the trigger on the welding gun is pulled. When the trigger is pulled it also switches on the current and shielding gas. You just need to pull the trigger of the MIG welding gun to start welding. The trigger on the MIG gun is just an ON-OFF switch.
An electric arc is formed between this wire electrode and workpieces. This electric arc heats both metals (wire metal and workpieces metal) above their melting points. These metals mix together and solidify to join the workpieces into a single piece. The metal pieces you need to join are called base metal and the metal that comes from a melting wire electrode is called filler metal.MIG welder always adds filler metal to the joint because the wire electrode melts and sticks to the joint.
On the MIG welder, there are settings related to wire speed, voltage, and polarity. For most MIG weldings, the current is direct current or DC. In DC MIG welding wire electrode is positive and the workpiece is negative. The term DCEP in polarity setting is used to indicate that the current is DC and the electrode is positive. For reverse polarity, the term DCEN is used which means the current is DC, and the wire electrode is negative.
DCEP polarity is used when less penetration into base metal is required. It increases the filler electrode deposition. Moreover, high productivity and good arc cleaning with less distortion are results of DCEP polarity.
DCEN polarity allows deep penetration into the base metal. Low filler metal deposition, low productivity, poor cleaning, and large distortion are results of DCEN polarity. AC polarity is used for a moderate effect.
Shielding gas is also fed through the MIG welding gun. Gas from the cylinder comes to the gas diffuser and flows out through the nozzle. This gas is usually Argon and CO2. Shielding gas protects the molten metal from oxidation due to reacting with oxygen, water vapor, or other things in the atmosphere. This shielding gas is stored in a high-pressure cylinder. Pressure reduces to usable levels by the regulator on the cylinder.
Advantages of MIG Welding
MIG was originally developed in 1940 for welding aluminum and other non- ferrous materials. After its introduction, the advantages of MIG welding have grown and grown popularly with time. All the advantages that I found while using my MIG welder are listed below.
1. MIG process is easy to understand and convenient to use
MIG is a one-hand operation. You just need to pull the trigger of the MIG welding gun to start welding. Just after pulling the gun trigger wire, feeding, current, and shielding gas start flowing. It means you can ensure safety with ease of operation at the same time. You can fix the speed of filling the electrode wire separately. Auto-feed wire offers the best control over the process. If you are new in the welding field than the MIG welding process is best to learn to weld. You can learn it in one day.
2. Fast electrode wire deposition rate increases productivity
The welder can enjoy a higher productivity rate through the MIG process. One-hand operation improves user control over the welding process as a result welding speed increases. You can also adjust the speed of the wire according to the requirement. If you need to do a taller weld you can increase the speed of the wire to save time. The welder doesn’t need to brush the weld repeatedly which saves time and increases productivity.
You can deposit more filler metal with each pass by increasing wire speed. When you have a long and complex weld you can get the job done with fewer passes which saves time.
3. You have excellent control over weld setting to manipulate your task
On MIG welder there is a setting related to wire speed, polarity, and amperage. If you need to weld on thinner material than you simply lower the arc amperage and use DCEP polarity. This setting allows you less penetration with increases in filler electrode deposition. Moreover, high productivity and good arc cleaning are achieved with less distortion.
If you need to do weld on thick metal than increase arc amperage lower your wire speed and use DCEN polarity. This setting allows deep penetration into the base metal with low filler metal deposition. There is a better chance of recovery from mistakes due to lower deposition rates.
You can also use AC polarity for a moderate effect. After getting the expertise you can use any combination of these setting to fulfill your task.
4. MIG welding does not need the metal to be perfectly clean
The best weld comes from pure clean metal to metal contact; any contamination in the welding area can cause welding imperfection. Even brand new metal has a coating to protect from oxidation during the shipping process. Be mindful, you need to remove this coating before welding.
The type of welding you are going to do will determine how well you need to prepare the metal. As compare to TIG welding you do not need the metal to be perfectly clean in MIG welding. So, less metal clean-up time requires in MIG welding.
5. MIG welding is clean you don’t need to remove slag and spatter after welding
When it’s come to electric arc welding, TIG is the king of cleaning but MIG is not that far behind.
Unlike stick welding, MIG uses a shielding gas to protect the arc. So, there is no flux involvement and slag generation to protect the weld. There is no slag clean job requirement in MIG welding.
MIG welder always adds filler metal to the joint because the wire electrode melts and sticks to the joint. So, there is a minimum spatter production in MIG weld. After MIG welding there is no requirement of a spatter cleaning job.
Spatter in MIG welding produces only when you set the excessive speed of feed wire with extreme heat due to high amperage arc. To avoid spatter set your machine parameters according to your job requirements. Moreover, adjust wire speed according to set amperage to minimize spatter problem.
6. MIG welding is versatile can work with many metals
In 1940 MIG was originally developed for aluminum and magnesium alloys but with time MIG welding became versatile and can weld a wide variety of materials. A wide range of filler wire electrode material and excellent control over weld setting make this process useful for the following metals: nickel, aluminum, stainless steel, magnesium, mild steel, copper, iron, and many other alloys.
Have a glance at the Advantages of Tig Welding it will help in comparison and selection as per your requirements.
Disadvantages of MIG
Nothing is perfect in this world. So every product has some drawbacks. As a wise man, our choice must be such products which suit us well and their disadvantages do not affect our work. Now, it’s time to describe some of the disadvantages of MIG welding.
1. Vertical up position welding with MIG is most difficult
You can use MIG welding in vertical or overhead welding positions. Vertical down position welding with MIG is pretty easy but vertical up position welding is difficult. Hint (you can build a shelf of weld to work upward on)
2. You need a special arrangement for the outdoor MIG welding process
MIG welder is not designed to use as a portable machine. A power supply source and shielding gas cylinder are required with the MIG welding machine. You can manage all these arrangements in your garage. But for outdoor welding, you need the generator for power supply and cylinder storage for shielding gas supply.
MIG uses a shielding gas to protect the arc. Shielding gas needs a stable atmospheric condition to protect the arc. Shielding gas can easily blow away by wind drafts. Without shielding gas the quality of the weld decreases due to porosity. You need to isolate the workplace by using a welding screen.
3. Relatively high initial cost and need for proper maintenance
The MIG welding machine is complex and needs proper maintenance for safety and quality reasons. You want to do the cleaning of weld nozzle, tips, diffuser, and liners regularly and replace them with new ones when needed.
A good MIG welding machine has a relatively high initial cost but it is designed for repair and maintenance. So, there is no need to replace the whole machine after a few years.
4. Not suitable for thin metal
There is a risk of burn-through if your workpiece is less than 5mm. If you’re a skilled person, you can get around this with MIG welding. But it’s generally accepted that TIG welding is more suitable for thin metal than MIG welding.
Conclusion
After my experience and research, I have described all the advantages and disadvantages of the MIG welding process. This detailed description helps to decide whether the MIG process is suitable for your weld or not. If you are never into welding than this article will also help you to understand the basics of MIG welding and all the Advantages of MIG Welding.
