Many different types of welding technologies are available in the industry right now, each offering a distinct set of advantages and benefits based on the application. So, it is easy to get confused while choosing the perfect option which suits your application the best. While doing so, you need a thorough understanding of the technology and how it differs from its alternative options on the market. You also need to consider the initial cost, running cost, and end result to make a decisive choice, especially for mass production.
The most common welding technologies in the industry are MIG welding and flux core welding. These technologies are always discussed when working with standard metals like steel, aluminum, or cast iron. Today, we are going to compare these 2 welding technologies and try to find out the best option for your job. But before we get to the comparison part, let us try to understand both welding technologies and what they offer in terms of advantages and limitations.
What Is MIG Welding?
Metal Inert Gas welding or MIG welding is one of the most common;y applied welding technologies for metal works. It is also known as Gas Metal Arc welding, which might confuse a beginner about its methodology. In this welding method, a continuous solid welding cable is fed to the welding pool by preheating it through a welding gun. Because of the applied heat, the base material is melted and fused together. The welding gun also feeds a shielding gas which is crucial for this process.
The process was first introduced back in 1949 for working with Aluminum. At that time, MIG welding was carried out using wire electrodes and Helium was used as a shielding gas. Since then, there had been a lot of changes in technology, and a variety of different inert gasses were used as shielding gas such as Argon, Carbon Dioxide, and even a mixture of 2 inert gasses.
Advantages And Limitations
Advantages of MIG Welding
- It is one of the easiest welding technologies
- Resulting weld is clean and free of slag
- Works well with thin metal workpieces
- There are little to no chances of improper wire feed
- Overall cost of the welding wire is lower
- Great results are observed with Aluminum
Limitations of MIG Welding
- Initial setup is a bit difficult
- Overall cost of the initial setup is higher along with higher running costs
- Metal preparation takes time before welding
- Surrounding environment affects the weld
- Not the best option for working with cast Iron
- Portability is compromised due to the gas tanks
What Is Flux Core Welding?
Flux Core welding, on the other hand, is one of the advanced welding technologies that was introduced shortly after MIG welding. This is a semi-automatic welding process that works in a pretty similar fashion to MIG welding. But, there are a few key differences that make the technologies differ from one another. Even the welding kit is quite similar for both technologies since flux core welding also needs a continuous welding wire feeder and a high-voltage power supply.
The key difference between the 2 technologies is the necessity of shielding gas. Though shielding gas is sometimes used in Flux core welding, it is not a crucial factor in the process. In this method, the heat generated by the electric arc is used to heat up the base metal to fuse the joint. Flux core welding requires a hollow and somewhat tube-shaped electrode with flux, unlike a solid metal electrode used in MIG welding.
Advantages And Limitations
Advantages of Flux Core Welding
- The process is easy to get used to, and best for beginners
- Initial setup is simple
- Suitable for outdoor applications
- Works well with thicker metal due to deeper weld penetration
- Comparatively affordable procedure
- Works well even with additional layers of paint of protective coatings
- Comparatively portable welding method
Limitations of Flux Core Welding
- Flux core welding produces slag
- Process take more time, considering the clean-up afterward
- Flux core welding does not work with Aluminum
- Higher penetration levels causes problems with thinner workpieces
Comparing Both Options
Now that you know how the welding technologies work, it should be pretty easy to compare the 2 methods based on their merits and demerits. If you want a quicker approach to that, we are presenting this handy comparison table that you can refer to before selecting the ideal method for your job. Here, we will take some important welding terminologies and compare MIG welding and Flux Core welding based on that.
| MIG Welding | Flux Core Welding | |
| Initial setup and complexity of the process | A bit more complex | Comparatively easier to learn |
| Cost of welding wire | Comparatively cheaper | Expensive welding rods |
| Gas tank | Required | Not necessary |
| Running costs | Higher running costs | Comparatively cheaper running costs |
| Surface preparation | Extensive care is needed | Works with impurities like dust, dirt, and even layer of paint |
| Effect of environment | Surrounding wind should be slower than 5 MPH | Up to 35 MPH wind speed has no effect on the process |
| Weld appearance | Clean and slag-free welding surface | Process creates slag and welding spatter |
| Post welding clean-up | Little to no clean-up is needed | Clean-up is needed |
| Compatibility with thin metal | Even 1/40-inch workpiece is weldable | Minimum required thickness is ⅛-inch |
| Compatibility with thick metal | Possible with higher power requirement | Up to ⅜-inch metal is weldable |
Similarities In Welding Technologies
Now that you know how the 2 technologies differ, let us try to understand the factors that make them appear similar to many. There are considerable similarities between MIG and Flux core welding that you should know before choosing either of the ones for your job.
First and foremost, both welding technologies need an automatic feed of welding wire fed to the welding zone. It makes the process quite simple since you don’t need to change the electrode every 5 minutes and you can perform long and continuous welds without affecting the integrity of the weld.
In both cases, the fed welding wire performs the function of an electrode. The wire carries current in both cases and also works as a filler material for the weld. So, it is crucial to avoid direct contact with the welding wire, whether you are performing MIG welding or flux core welding.
Another similarity in both cases is the equipment and the setup. A lot of manufacturers offer combined machines that can be used for either process by changing a few parameters such as polarity and voltage level.
Differences In Welding Technologies
When we are discussing the differences between MIG welding and flux core welding, we need to take a look at a few factors individually and see how and why they are different in both cases. This will allow you to thoroughly analyze the process and choose the one that seems like an ideal candidate for the process. Here, we will discuss the differences in both welding technologies based on some important aspects such as the need for shielding gas, polarity difference, welding strength, and much more.
1. Need For Shielding Gas
The only factor that creates a noticeable difference in both technologies apart from polarity is the necessity of shielding gas. In a MIG welder, a gas tank is always included since it is crucial for the process. Along with the welding wire, the shielding gas is also fed to the weld zone to protect it from the impact of the surrounding environment.
On the other hand, flux core welding allows the use of shielding gas, but it might as well be performed without it, and you won’t notice much difference. It is because of the flux used alongside the welding wire, which acts like a protective shield to minimize the impact of the surrounding air. The flux reacts with the hot weld pool and turns into the protective gas, eliminating the need for an external gas supply.
2. Type Of Welding Wire
Another difference between the two technologies lies in the type of wire used for the welding. In MIG welding, a solid wire is used since the wire itself does not contain flux. It also reduces the types of wire used for the process, making the choice of wire simple and straightforward based on the type of job.
The story is a bit different when it comes to flux-core welding. Basically, the core of the flux core welding wire is hollow, which is later filled with a core wire of alloying metal and flux. Therefore, you need to carefully check which welding wire you are buying and whether it is suitable for the job or not in the case of flux core welding.
3. Difference Of Polarity
Polarity is a major difference between the two welding choices, and it can completely change the welding process if you are using a kit that allows both technologies simultaneously. In the MIG welding setup, the electrodes are set as positive, whereas the workpiece is a negative pole. Therefore, more heat is concentrated on the workpiece instead of the electrode.
In Flux core welding, the electrode is usually set as the negative pole, and the workpiece is kept positive. In this condition, more heat is concentrated in the electrode instead of the workpiece. But with that being set, choosing the MIG welding polarity, or DCEP polarity settings sometimes favors flux core welding. So, keep that in mind and select the best polarity settings based on the job.
4. Type Of Filler Material
Since the MIG welding method uses a solid wire which is made up of the same metal or alloy that you are welding, it is a more forgiving process and allows multiple torches to pass without any problem. The quality of the filler material is also somewhat pure in this case, given that you are using a premium option for the welding wire.
In a flux core welding wire, there are additives in the core of the wire, as we observed before. So, the addition of flux alongside the metal changes the composition of the filler material upon heating. It also makes the wire suited for a single pass. Therefore, a lot of welding wires designed for flux core welding are rated for a single pass only.
5. Welding Strength
Even though the composition of the filler material is somewhat compromised in flux core welding, both technologies create a strong welding bead that can be used for mass production industry and heavy-duty applications. However, one thing that is the same for both cases is that the welding parameters should be correct, and the right welding technique should be used.
The only time you will notice a difference in welding strength between flux core and MIG welding is when you are working with cast iron. Due to the added benefit of material penetration, it creates a stronger weld with cast iron and MIG welding lacks a little in this case.
6. Weld Penetration
As we mentioned earlier, material penetration is one of the important benefits of flux core welding, which makes it a suitable choice for many jobs. The main reason behind that is a concentration of heat, which is higher in flux core welding compared to MIG welding. For the same welding amperage, the penetration levels are better with flux core welding.
This certainly creates a difference when you are working with these metals, granting an edge to flux core welding. But, it also causes incompatibility when you are working with relatively thinner workpieces. The concentrated heat causes excessive penetration of the material that does not bode well with thin metals.
Which Welding Technology Is Better?
It is not possible to grant one welding technology an edge over the other since both of these options offer a wide range of benefits. Also, both options come with a set of limitations that can be a dealbreaker in your case. So, the best way to determine the compatible option for your task is by checking the differences between both options based on some important factors that we are mentioning here.
1. Need For Surface Preparation
If you have worked with MIG welding before, you know the importance of surface preparation in this technology and how it can result in a variety of welding defects if proper surface preparation is not maintained. While working with MIG welding, the welding surface needs to be completely free of the outer layer, including the layers like protective coatings, oils, paint, and even rust.
On the other hand, the need for surface preparation is not that crucial in the case of flux core welding. In fact, the flux used in flux core welding reacts with the surrounding area and cleans the metal oxides and impurities. Therefore, it can easily weld the surface without the need of surface preparation.
2. Looks And Appearance
One of the disadvantages of flux core welding is the formation of slugs and splatter, which decreases the aesthetic appearance of the weld and also comprises the composition of the workpiece. Thus, considerable cleanup is needed after performing flux core welding to improve the appearance of the welded surface.
MIG welding, if performed correctly, causes minimal welding defects. Most of these defects are not even visible to the naked eye, offering a clean and polished welded surface. So for aesthetic products and decorative objects, MIG welding is definitely a good choice.
3. Outdoor Applications
Another important factor to consider before choosing the right welding method for your job is the job location. If you are going to perform welding outdoors, then flux core welding is going to offer you much better results than its alternative. MIG welding, as you already know, needs a shielding gas that can get affected by the surrounding air. In the comparison table, you can see that the surrounding wind speed has to be less than 5 MPH for efficient MIG welding performance.
Flux core welding, on the other hand, allows up to 35 MPH surrounding wind speed without any noticeable effect on the welding results. Thus, flux core welding is the right choice for outdoor applications, especially when the welding job is to be performed at a height such as a construction site or a rather windy location.
4. Welding Cost
Another thing that creates differences in the applicability of the process is the welding cost. In comparison, the welding wire used for flux core welding is definitely more expensive than the one used for MIG welding. However, it only indicates the running cost of the process which can vary from application to application based on the need for welding wire.
The more important factor, in this case, is the initial cost of setup and the cost of the equipment that you need to have. Here, MIG welding definitely appears to be more expensive than flux core welding. There is an added cost of the gas tank in MIG welding along with the added cost of the welder. The best option would be choosing a welder that allows both welding operations to save future expenses.
5. Best Option For Cast Iron, Steel, and Aluminum
a. Cast Iron
As we mentioned before, the best option to weld cast iron is flux core welding. It will offer efficient penetration of the workpiece so that the weld strength will be suitable for heavy-duty applications. Also, you can easily find a flux core welding wire that has a cast iron core along with the flux material at an affordable price range.
b. Steel
The situation is a bit different in the case of steel and it depends upon the type of steel you are using for the job. For example, for galvanized steel, surface preparation becomes important for MIG welding since it cannot penetrate through the galvanized layer without causing welding defects. On the other hand, flux core welding can very well weld through the layer just like any other layer of impurity.
c. Aluminum
Aluminum is best welded by MIG welding since you can expect a good quality finish which is to be expected on Aluminum objects. Also, it can be quite difficult to find a welding feed wire for Aluminum for flux core welding that can ensure good results. But, you can easily find solid Aluminum wires, offering an edge to MIG welding in the comparison.
Conclusion
MIG welding and flux core welding might appear identical to beginners due to the similarities in the process and equipment used in both methods. But, it is definitely not the case as the end results are quite different with both welding methods for various metals. So today, we have brought you an in-depth comparison of flux core and MIG welding along with the factors that you need to know to understand the differences between both options. So, make sure you go through our guide completely and check the parameters carefully before selecting a method for your job.
