GMAW vs FCAW – What is The Main Difference Between Both

You might know that welding is not of a single type only. There are multiple types of welding, each having its own set of perks and drawbacks. Among these types, gas metal arc welding (GMAW) and flux-cored arc welding (FCAW) are quite famous. These two types come under the category of arc welding.

So, what is the main difference between the two? Well, when you talk about GMAW vs FCAW, the main difference is their electrodes. They basically have different electrodes from one another, whereas many other features and properties are the same.

Here, we will discuss the difference between GMAW vs FCAW, GMAW vs SMAW welding, SMAW vs FCAW, and the advantages of all these welding types.

What is GMAW?

Gas metal arc welding (GMAW)

You might have seen gas metal arc welding GMAW in your nearby workshop since it’s very common. There are numerous applications of this welding type because it is easy and fast, and the welding machine is quite affordable. The process is adaptable and can be adjusted based on the project requirements. GMAW is perfect for steel and alloys.

It was developed in 1940 to weld aluminum and some non-ferous materials, but then its use shifted to steel materials. In the beginning, only inert gas was used, so the cost was high.

Later, the introduction of active gases like carbon dioxide and a mixture of argon and carbon dioxide became more common and that’s why it has become common to use for steel materials.

GMAW Process

It is famously known as metal inert gas (MIG) welding, where a constant wire electrode is fed through a welding gun shielded by inert gas, applied separately. This technique involves:

• Electric power supply
• Wire electrode
• Shielding gas

You feed the wire and shielding gas through a welding torch. You need a uniform voltage to maintain the arc length. It should be compatible with the wire feed speed.

There are number of ways you use GMAW. You can make it automated, semi-automated or keep it manual.

If you are performing manually, you need to hire a welder who is experienced and knows about the technique. It is operated by either DC or AC.

This technique is particularly important when you need the weld joint to be very strong. It transfers metal through four methods: globular, pulse-sprayed, short-circuiting, and spray. The following are some of the materials you can weld through GMAW:

• Stainless steel
• Aluminum
• Magnesium
• Silicon bronze
• Carbon steel
• Nickel alloys
• Copper alloys
• Tubular metal-cored surfacing alloys

GMAW Advantages and Disadvantages

GMAW offers a range of advantages, from low cost to high welding quality. There are several industries that make use of this amazing technique since it is affordable and effective for long term projects. Below are some of the main GMAW advantages:

• Cost-Effective Process

One of the benefits of gas metal arc welding is its efficiency at higher speed. Though many people argue about the pros and cons of bare wire GMAW, but still, the initial setup cost of GMAW is far less compared to other types of welding processes.

It allows the use of different gas mixtures and not just argon, which is very expensive. Many welding techniques are costly because they use only argon. And if you use those on a high-end busy site, the cost adds up a lot.

Because of the presence of a continuous electrode feed, performing GMAW is much easier for the welders.

When you automatize the process, it becomes more easy for the welder to put in less effort but get a greater output. It can handle not only smaller tasks but bigger ones too, and can easily replace processes like resistance welding, riveting, silver soldering, and brazing.

• Efficiency

GMAW is more efficient than other types of welding for the operator. He can set the equipment very easily. It’s equipment is controlled and is not complex. The welders only need to take care of the torch angle, and electrode stick-out, manage the weld pool, and control travel speed.

• Accuracy

There is a minimum amount of distortion in GMAW. Since it uses solid wire electrodes, there is less spatter and slag compared to others. This makes it easy to clean and manage. Less spatter and slag means the finishing is smooth and even.

Because of this, the cost is reduced even more as you don’t have to put in extra money for surface finishing. Moreover, the rate of fumes and heat production is less in GMAW than in the other welding types.

• Flexibility

It is not limited to only one position or material. You can use it for any position and employ on multiple materials, whether light or heavy. If you are working with a heavy material, keep the groove angle narrow and the root face should be thick. It reduces filler buildup and hence, decreases preparation time. GMAW allows higher current concentration than others, leading to better penetrations.

There are some GMAW disadvantages too. We have mentioned the most important ones below:

• If you don’t set and control the welding parameters before and during GMAW, it can leads to lack of fusion.
• The welding gun is difficult to use in confined spaces.
• You can do GMAW in windy outdoor sites since the shielding gas blows away with the wind.
• Since there is no slag system, doing GMAW for difficult positions is not as effective as other techniques.

What is FCAW?

Flux-cored arc welding (FCAW)

You can also call it dual shield welding and it has similar advantages and features of gas metal arc welding. It uses the same equipment as GMAW. It’s history goes back to the 1950s when it was started in place of the manual metal arc welding (MMAW).

Why? Because it was reported that this technique is more efficient and produces defect-less welds. It is more successful than MMAW since it uses a constant wire fed electrode like GMAW.

Though it uses a shielding gas to operate. Unlike GMAW, FCAW can operate without shielding gas.

FCAW Process

FCAW uses heat produced by an electric arc for fusion, and the welding process is similar to that of gas metal arc welding.

The electrode used in FCAW is a hollow and tubular flux-filled electrode instead of a solid wire electrode in GMAW.

Flux-cored welding can be performed through two methods. You can either use an external shielding gas for performing the welding or do it without the shielding gas where the flux-filled electrode itself produces its own shielding gas.

Shielding Gas Method

The shielding gas method is the one which uses an external high pressure shielding gas like GMAW to offer protection against contamination. It also prevents the slag formation of weld metal from flux electrode material.

That is why this technique is called dual shield welding. It’s most common application is to weld structural steel. The primary shielding gas used is carbon dioxide. It is also very common to use a CO2 (25%) and argon (75%) blend as shielding gas.

You can use this ideally for thick materials, particularly the ones with difficult welding positions. Instead of GMAW for similar setup and conditions, this process has much smoother results and welds with less defects.

The use of continuous hollow tubular flux electrode gives a better production rate compared to MMAW and GMAW.

However, you cannot use the shielding gas method in outdoor windy conditions like GMAW. The wind blows the shielding gas away from the workpiece and the welding will not be possible.

Non-Shielding Gas Method

This method doesn’t use external shielding gas and provides protection through the flux-filled electrode itself.

It not only offers gaseous protection but also forms slag covering and protecting the molten metal. Since you are not using any external gas, it can be used outdoors in windy conditions, making it versatile and portable.

The following are some of the materials that are compatible with FCAW:

• Cast iron
• Carbon steel
• Hard facing
• Surfacing alloys
• Stainless steel

Advantages of FCAW

There are dozens of advantages of FCAW. Let’s see the most common benefits offered by flux-cored arc welding process.

• High Speed

Compared to stick welding, FCAW enables the welder to do faster welding, which is perfect for high production applications where efficiency is important.

• Exceptional for Thick Materials

Since it produces deeper penetrations, this welding technique is excellent for thicker materials, and hence, it decreases the need for repeated passes.

• Position Versatility

You can use FCAW for complex applications and repairs because it caters to different welding positions including vertical and overhead positions.

• Perfect for Outdoor

The flux-filled self-shielding electrode makes FCAW ideal for outdoor projects as there is no external shielding gas involved in the process.

• Less Preparation Required

There is minimal need for welding preparation as the self-shielding flux electrode protects from contamination.

Disadvantages of Flux-Cored Arc Welding

Though there are many advantages of FCAW, it has different limitations as well. Some of the disadvantages are listed down below:

• Requires Slag Removal

Slag is produced as a result of FCAW, and you need to remove it after the welding process to make sure the finish is smooth and clean. It needs extra effort and time from the welder.

• Additional Equipment Cost

FCAW welding gun and wire feeder are considerably more expensive than the stick welding (shielded metal arc welding) technique.

• Limitations for Thin Materials

This welding process is not the best for thin materials because it causes burn-through and warping of material because of the excessive heat production.

• Emission of Fumes

Flux-core arc welding produces more sparks and fumes as compared to the other types of arc welding, so increases safety concerns for the welder. You need proper ventilation for the process.

GMAW vs FCAW: A Comparative Analysis

GMAW and FCAW are two welding processes that have advantages and disadvantages of their own. We have made a table highlighting the important differences between GMAW vs FCAW.

GMAW vs SMAW Welding

We have talked about GMAW already in the above section. In this section, let’s see if GMAW and SMAW are alike. How they are different through a detailed comparison table.

Shielded Metal Arc Welding (SMAW)

Shielded metal arc welding has good versatility and you can use the techniques in several applications and industries. Like flux-cored arc welding, SMAW also has a consumable electrode that is flux-coated to produce its own shielding gas and provide protection against environmental gasses. Therefore, the welds produced by SMAW are likely very smooth and precise. It’s a simple, affordable, and versatile welding technique. Besides, it is effective for outdoor applications and repair projects.

So, what is the difference between SMAW and GMAW? Let’s see a comparison between GMAW vs SMAW welding.

SMAW vs FCAW

Shielded metal arc welding (SMAW)

Flux-cored arc welding (FCAW) and shielded metal arc welding (SMAW) are two very popular arc welding techniques due to their effectiveness in outdoor conditions where the environment is harsh. Both of these techniques use a flux that produces shielding gas of its own. Hence, you can use them in a windy atmosphere too.

Despite these similarities, there are some differences between SMAW vs FCAW based on their applications, efficiency, and versatility. SMAW is very cost-effective and movable. That’s why it is perfect for repairs and construction site usage.

The welding speed of FCAW is much higher and, hence, suitable for industrial scale applications. Below is a comparison table between SMAW vs FCAW:

Conclusion

The welding process is very important for construction, repair, aerospace, automotive, pipeline production, tank fabrication, and so many other industries.

Among different welding types, arc welding is a famous one. Three very common, efficient, and versatile welding techniques are: Gas metal arc welding (GMAW), flux-cored arc welding (FCAW), and shielded metal arc welding (SMAW).

Though their features, characteristics, and benefits are different from one another, they have so many similarities among them.

The difference between GMAW vs FCAW is their electrode. GMAW has a solid wire electrode, whereas FCAW has a flux-coated wire fed electrode. There is another type we mentioned in the guide which is SMAW.

Their weld pool is protected by flux-coated electrodes so they also don’t need additional shielding gas. Only gas metal arc welding (GMAW) uses an external shielding gas to protect the weld pool from contamination.

So, it’s important to know the differences between welding techniques to practice every technique with the right knowledge and improve it accordingly.