Understanding Different Welding Types and Applications

Welding is a crucial process in various industries, from manufacturing to construction, automotive, and even aerospace. With its diverse applications, understanding the different types of welding methods and their uses can help determine the best approach for a specific project. Whether you're a beginner looking to explore welding or an experienced professional refining your skills, it's essential to recognize how each welding technique differs in terms of materials, equipment, and end results. In this article, we'll dive into the most common welding types, their unique characteristics, and where each method excels.

1. Gas Metal Arc Welding (GMAW/MIG)

Gas Metal Arc Welding (GMAW) is commonly known as Metal Insert Gas (MIG) welding. It is an incredibly popular welding method because of its versatility, speed, and weld quality.MIG welding is a type of arc welding process. It uses a MIG gun that contains the metal wire electrode fed through a motor. A spool of suitable wire is used, which is available in different diameters or thicknesses and chosen according to the application.

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Working Principle and Process

The arc is produced between the metal wire electrode and the working pieces. The temperature of the material increases, and a molten pool is created. The metal wire is also consumed to fill the gap between the pieces and create a perfect weld.

A shielding gas is also used in MIG welding. The hose is connected to the MIG gun. It could be a 75% Argon & 25% CO2 mixture, 100% CO2, or any other suitable inert gas or mixture. Its job is to protect the molten pool from contaminants in the air.

The wire or MIG gun is usually made the “+” terminal, while the working piece or welding table is made the negative terminal. When these two terminals connect together, they create an arc, which is capable of increasing the temperature of the metal quickly and turning it into liquid.

While doing MIG welding, two core variables are controlled, Voltage and Wire Feeding Speed (WFS). The welder has to set the appropriate values for these according to the material, thickness, wire size, and some other factors. Usually, there is a chart given by the MIG welding machine manufacturers to make the process easier.

When and Why Choose MIG Welding?

MIG welding is one of the easiest types of welding and is a good choice for beginners. It requires one hand, the wire is automatically fed, and the control is extremely simple. Welders need to master the work distance, gun angle, drag angle, and speed to achieve excellent welds, and all of these come with experience.

It is an ideal option to join a variety of materials, including stainless steel, carbon steel, mild steel, aluminum, copper, nickel, titanium, bronze, and magnesium.

The speed of MIG welding is incredible. That’s why it is used in industrial manufacturing to enhance productivity. It saves time without compromising the weld quality. It can also be automated through robotic hands.

The weld quality is amazing. It is suitable for welding thin sheets and objects. It joins metals very well, and minimal post-processing is required. Some common use cases of MIG welding are joining metal sheets, making car bodies, metal fabrication, construction, shipbuilding, repairs, etc.

Limitations

If you want to join thick metals, MIG isn’t the right option. Secondly, you can’t do MIG welding outdoors due to wind. The wind blows out the gas and affects the weld quality.

You can weld flat surfaces really well, but when it comes to vertical or overhead welding, MIG can’t work because of the molten pool.

Last but not least is the gas cost, which makes the process a bit expensive.

2. Shielded Metal Arc Welding (SMAW)

Shielded Metal Arc Welding (SMAW), which is commonly known as Stick Welding. It’s also a type of arc welding, specifically manual arc welding. It is the most commonly used welding method because it’s cheap, simple, and portable. It’s an excellent option for DIY tasks, outdoor welding, and simple jobs.

There is a simple SMAW machine that is compact and easy to carry. A welding stinger is used to hold the consumable electrode. The stick or electrode has a covering called flux, which assists in the welding process.

It is called manual arc welding because it is a completely manual process. The welder is responsible for controlling the welding speed, arc length, and electrode angle.

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Working Principle and Process

The welding stinger is connected to one terminal of the welding machine, either negative, positive, or AC, depending on the type of electrode, welding material, etc. The second terminal is connected to the workpiece.

The stinger holds the electrode or stick, so it can also conduct electricity. When the stick comes in contact with the working piece, an arc is created. This arc is enough to increase the temperature of the metal to the melting point and create a molten pool.

The stick is also consumed in the welding process. It acts as a filler material and helps fill the gap created. The coating or covering of the stick is also consumed. Some of it is converted into gases that shield and stabilize the article. While the rest of it is converted into a layer of slag that rests over the molten pool. It protects the weld from contaminants and shapes the weld.

The weld pool is solidified when the stinger moves forward. Once it is completely cooled down, the slag is removed.

When and Why Choose Stick Welding?

You can weld all ferrous materials using stick welding. You can use it for cast iron, stainless steel, and carbon steel. It can also be used for non-ferrous metals, such as nickel, copper, and aluminum.

Stick welding is a straightforward process. Welders choose the right voltage and welding current according to the working piece. Its quality greatly depends on the skill of the welder.

It is used for a wide range of applications. You can do stick welding almost anywhere. It is not affected by wind, so you can use it outdoors. It can do welding in any position, be it horizontal, vertical, or overhead.

Welders prefer stick welding for common tasks. It is portable and can be carried anywhere. It is mostly used for household jobs and repairs. The best part—it does not require an exceptionally clean piece as it can even weld on rust pieces.

Some of its use cases are in construction, shipbuilding, maintenance & repair, etc.

Limitations

Stick welding is a slow process. The welder has to go slowly and change the electrode frequently, and even after, welding excessive post-processing is required. The slag on the weld is chipped off with hammers, wire brushes, and other mechanical means.

The weld quality is not as good as other welding processes. It isn’t smooth, and there are holes and cracks. Secondly, the weld is less durable. It’s not suitable for heavy-duty applications.

Stick welding is not suitable for thin materials. It can pass directly through and make holes. The materials it can weld are also limited.

Another challenge of stick welding is that it can’t be used in confined spaces due to the length of the electrode. And the fumes and spatter it produces require extra care.

3. Gas Tungsten Arc Welding (GTAW/TIG)

Tungsten Inert Gas (TIG) welding or GTAW is a type of arc welding that uses a non-consumable tungsten electrode. It is preferred for its versatility and incredible weld quality.

The equipment includes a TIG welding machine, a TIG torch, and a filler material. The torch contains a long piece of tungsten that can be adjusted as required.

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Working Principle and Process

The tungsten is the non-consumable electrode. When it comes near the base material, the circuit is completed. It creates a spark that is capable of generating immense heat. It quickly turns the material into liquid. The heat can be controlled by the welding through the torch or foot pedal, and it is adjusted according to the base metal.

The filler material can be used to fill the gaps. It is not needed in all cases. The welder has to hold the torch with one hand and the filler material with the other. Therefore, two hands are required for this welding type.

A shielding gas is also needed to protect the weld pool. It prevents oxidations and protects from the atmospheric contaminants.

When and Why Choose TIG Welding?

TIG welding offers incredible weld quality. It can precisely weld materials, which is why it is an ideal choice where aesthetics is important. Not only does the weld look clean but it is also quite strong.

It can weld a wide range of metals, including steel, aluminum, copper, cast iron, bronze, brass, magnesium, nickel, and various alloys. Undoubtedly, it is the most versatile welding type.

It is an excellent option for thin metals. You can join metal sheets and intricate pieces. The welder can control the heat to a great extent, which makes it a perfect choice for delicate items.

TIG welding is used for welding aircraft components, car chassis, art sculptures, and even things and intricate materials.

Limitations

TIG welding is a relatively slow process. The welder has to weld slowly while using both his hands. It also requires a high level of skill to weld with perfection.

It’s a complex welding process suitable for expert and educated welders. It is not suitable for DIY and common jobs. The welding equipment is also very expensive.

Another issue with TIG welding is that it’s prone to contamination. It can easily get contaminated with dust particles and grease on the surface. Therefore, proper cleaning is essential for a clean weld.

4. Flux Cored Arc Welding (FCAW)

Flux Cored Arc Welding is a bit similar to MIG welding in some aspects. It also uses a consumable wire electrode; however, it’s tubular, which means it has a flux-filled inner core. It also has a wired feed unit that drives the wire electrode into the FCAW gun.

Flux Cored Arc Welding can be divided into two types. One is called the Self Shielded or FCAW-S, and the other is called Gas Shielded (FCAW-G). The first one does not require a shielding gas and the wire is more than enough, while the second one requires a shielding gas for the process.

However, when welders refer to FCAW, they generally refer to the Self Shielded method.

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Working Principle and Process

In FCAW-S (Self Shielded), the wire electrode comes into contact with the base and creates a spark. The heat generated in the process melts the metal and creates a pool.

The wire electrode serves as the filler material. It fills the gap and makes the weld stronger. The inner core of the wire contains flux, which also goes into the pool. It also creates a slag that floats over the molten pool and protects it.

Once the pool solidifies, it’s time to clean it. Hammering or wire brushing is used to remove the flux and reveal the weld beads.

During the welding process, the welder has to slightly oscillate the torch to achieve perfection. It also makes the weld bead wider, which translates to increased deposition.

When and Why Choose FCAW Welding?

FCAW is a great choice when a strong weld is needed. Its deposition rate is extremely high, which means it deposits a lot of filler material in the weld pool, making the final weld stronger. For the same reason, the speed of the welding is also faster.

You can use FCAW-S even in windy conditions. There is no gas needed, so you can weld outdoors with perfection.

It can weld various metals, including cast iron, stainless steel, carbon steel, and nickel alloys. It is generally used for thick materials. Common use cases include steel structure fabrication, construction, pipeline welding, heavy equipment manufacturing, chassis welding, etc.

Limitations

If you need seamless welds, you shouldn’t go with FCAW. It has a high deposition, which is clearly visible. So, the aesthetics are compromised. It’s also not suitable for thin and intricate items.

A major issue with FCAW welding is heavy smoke formation. It requires proper ventilation. Otherwise, it could affect the health of the welder.

Last but not least is the high operational cost. The electrode wire is expensive, even more than the one used in MIG. It requires exceptional skills to create perfect welds and prevent porosity. Moreover, it can weld fewer materials compared to MIG.

5. Laser Welding

Laser welding is a bit different from the other welding methods we have discussed. It’s a contactless welding process in which a laser source is used to weld metals and thermoplastics.

It uses a powerful laser source that emits a highly focused laser beam. It joins materials with excellent precision and accuracy and offers aesthetic welds.

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Working Principle and Process

The laser beam is focused on the welding area. It increases the temperature of the area in no time as the beam is concentrated on a tiny spot and the energy density is extremely high. It releases excessive heat and creates a molten pool of the metal.

As the laser moves forward, the molten pool behind starts to solidify. After cooling, a strong metallurgical bond is created.

When and Why Choose Laser Welding?

Laser welding is the most accurate and precise welding method of all. The reason is its highly focused laser beam. It can even target a tiny area, which is why it can deal with intricate welds.

It welds materials at an incredible speed. It requires almost no time to melt the material. Therefore, it increases productivity and helps in meeting customer demands. In some industries, laser welding is controlled by robots.

It is possible to control the power, speed, frequency, and other factors to make perfect welds that are aesthetically pleasing. It does not require any post-processing, which also saves time. You always get a clean and smooth weld.

The best part is that laser welding only targets the welding area. The surrounding area is not affected. The heat-affected zone is minimal. Therefore, there is no chance of material deformation or damage to the surrounding elements.

The operation cost of laser machines is also low. They do not require any consumable electrodes, filler material, etc. It uses less energy as it targets a small area and welds the material in less time. However, the upfront cost is high.

Laser welding can be used for a wide range of metals, including steel, aluminum, copper, nickel, magnesium, titanium, gold, and silver. It can also weld plastics, such as acrylic, nylon, polycarbonate (PC), polyethylene, and thermoplastic polyurethane (TPU). Almost any material that can be melted and solidified can be laser welded. Therefore, it is an extremely versatile welding method and has no comparison.

Some common use cases are welding of aircraft & spacecraft, car bodies, medical instruments & equipment, electronic components, jewelry items, etc.

Limitations

The upfront cost of laser machines and other accessories is quite high. However, it is becoming affordable over time.

The penetration of the laser beam is limited, and the reasons could be power, reflection, plasma, etc. Generally, it can’t produce very deep welds. It’s not suitable for thick materials.

Mastering laser welding requires enough knowledge. Extreme skills and experience are needed for perfect welds. Finding people with the right skills is difficult.

The major problem of laser welding is safety. It must be handled with extreme care. If it is reflected, it can harm the operator and objects nearby, and even start fire. It must be properly enclosed and proper gear is needed for operation.

Conlusion

We can categorize welding into more than a dozen types and sub-types. However, these five are the primary welding methods and are widely used in various industries. Each welding method has its own characteristics, benefits, and limitations. It is necessary to select the right welding method for the job to get excellent weld quality. We have discussed all these welding methods in detail and hope the guide can help you understand different welding types and applications.