4 Different Types of Welding Processes & Pro tips

Becoming a steel fabricator or a welder can be an intimidating job role. But, at the same time, it is a very empowering, rewarding, and exciting profession. It needs proper skill and professionalism to be a welder.A welder can convert different types of metals into various forms and shapes using their equipment and material. If you are a good welder, you surely are very enthusiastic about your profession.Apprentices should start from the basics to reach professionalism in this field. Otherwise, the output will not be satisfactory or worth the time spent on the job. Therefore in this article, we will start from the basics. Let us discuss the types of welding process.

What are the types of welding process?​

Before checking on types of welding process, let’s have a quick understanding of ‘Welding‘.

Welding is a process of fusing metals or thermoplastics seamlessly, applying heat and pressure on the fusing materials. Filler materials are also used in the process when needed.

You know what; many items around us have gone through this welding process. Or, many have at least a piece that is welded or made by machines that were welded. Your precious jewelry, your car, the stainless steel pan, all are welded.

What is ‘Weldability,’ then? It is ‘the capacity of being welded into inseparable joints having specified properties such as proper structure, definite weld strength, etc..’ A certain material’s melting point, thermal expansion, thermal conductivity, surface condition, and change in micro-structure can affect its weldability.

Welding types and welding process types are not the same. Do not get confused between the two. There are two major types of welding: Plastic welding/ Pressure welding and Fusion welding/ non-pressure welding.

Plastic welding or pressure welding uses external pressure on the metal pieces, which are heated to a plastic state. In fusion-welding/ non-pressure welding, heat is applied on to material at the welding joint till it is molten and then allowed to solidify.

When it comes to types of welding processes, there are more than 30 subtypes. Among them, only a few are used frequently.

Below are the welding process types seen in the industry.

Welding Process types​

1. Gas Welding Process
   • Oxyacetylene
   • Oxy-hydrogen
   • Air-acetylene
2. Arc Welding Process
   • Carbon Arc
   • Metal Arc
   • Gas Tungsten Arc
   • Gas Metal Arc (MIG)
   • Plasma Arc
   • Atomic-hydrogen Arc
   • Flux-cored Arc
   • Submerged Arc
   • Electro-slag
3. Resistance Welding Process
   • Spot welding
   • Seam welding
   • Butt welding
   • Percussion welding
   • Projection welding
4. Solid-State Welding Process
   • Ultrasonic
   • Friction
   • Explosive
   • Diffusion
5. Thermit Welding Process
6. Other New welding Processes
   • Laser welding
   • Electron beam welding
7. Other related processes to welding
   • Soldering
   • Oxyacetylene cutting
   • Brazing
   • Arc cutting
   • Hard Facing

Common Types of Welding Processes​

With the development of technology, these welding processes have developed to a great extent too.

The advanced tools and equipment make the work more efficient and neat. There are many automatic machines and systems for the welding processes at present. Yet, intelligent manpower is still essential in doing the job right.

A skilled welder knows which process to choose from the different types of welding processes. Understanding the differences and selecting the most appropriate process is crucial to give the needed output.

However, among all the above-mentioned welding processes, only four types of welding processes are commonly used at present. They are,

1. Arc Welding- also known as Shielded Metal Arc Welding (SMAW)
2. Gas Metal Arc Welding (GMAW) – also known as Metal Inert Gas Welding (MIG)
3. Gas Tungsten Arc Welding (GTAW) or tungsten Inert Gas (TIG)
4. Flux-Cored Arc Welding (FCAW)

We will discuss more on these four major welding processes further through this article.

Arc Welding/ Shielded Metal Arc Welding (SMAW)​

Arc welding or Shielded Metal Arc Welding (SMAV) is the most basic welding type among all types.

In the industry, this process is also known as ‘Stick’ in simple terms. A welding stick, or a welding rod, which is the consumable electrode, uses an electric current to melt itself and make the weld.

These consumable electrodes have a chemical cleaner or a flux core, which prevents oxidation of the weld. There, the molten metal stick is shielded from oxides and nitrates in the atmosphere.

If oxidation happens, the weld gets weakened. Because of this, the Shielded Metal Arc welding is suitable in construction, steel erection, pipeline welding, and heavy equipment repair.

Safety precautions during Arc Welding​

• The welder must protect his eyes and ace while using the arc, as there is a high intensity of light and heat rays emitting from it.
• A hand shield or a protective helmet with a colored glass face guard should be worn while working.
• The welder must wear heavy protective gloves.
• The arc should be placed in a covered or screened area, to protect other people from its glare. It is not safe to sight that glare with naked eyes.

Gas Metal Arc Welding (GMAW)/ Metal Inert Gas Welding (MIG​

Gas Metal Arc welding or MIG is the welding process that uses a wire connected to an electrode current when combining two metal pieces together.

The consumable electrode is continuously fed using the welding gun. GMAW is a high deposition rate welding process which is most common among all types of welding processes. It is also considered as a semi-automatic welding method.

This process needs a direct current and a constant voltage. Gasless MIG is known as flux core. We will discuss Flux Core welding on another topic.

Gas Metal Arc welding is less costly as the wires used are not very expensive, and also, the final output of Gas MIG is much cleaner and neat.

This welding process is very commonly seen in the automotive industry as this weld is much stronger to withstand large forces. It is easy to learn this welding type making it the highly preferable welding process among beginners for DIY projects.

The power given during the welding should be adjusted to match the thickness of the metals to be welded.

Welding speed also matters in making a perfect weld. This speed affects the penetration of the weld. Therefore choosing the appropriate settings is essential in MIG.

Apart from the automotive industry, robotics, maritime industry, and constructions, etc. use this welding process in their work. Gas Metal Arc Welding offers functional versatility and strength and is commonly used on Steel, magnesium, and aluminum metals.

Safety Precautions during Metal Inert Gas Welding​

As shielding gas and wire feeders are used during the GMAW process, welders should take all the safety precautions to avoid accidents.

A droplet of molten metal from the hot electrode can penetrate through a glove to touch the hand. Inhaling excess shielding gas can easily suffocate the welder and make him pass out.

Many deadly accidents have happened due to shielding gases. Let’s check the safety measures for MIG.

• The welder must wear a safety helmet with a shade to protect eyes from UV radiation. The shade should match with the welding voltage to avoid accidents.
• To save your eyesight and eyes from welding sparks, welders must wear safety glasses or goggles.
• Welding gloves with the reflective coating will protect the welder’s hands from burns and electric shock.
• Wear leather boots to keep your feet protected from sparks and molten metal pieces
• Welding should be done in a well-ventilated space while not spreading the gas away from the welding area.
• Protective overalls or long-sleeved tops and long pants made using fire retardant material should be worn during the welding job.
• Protective helmets must avoid welding fumes and shielding gases entering your breathing system. Stainless steel and aluminum welding fumes are extremely bad for our health, which can lead to cancer in the long run.
• Wear protective earplugs or earmuffs to avoid sparks entering your ears.

Gas Tungsten Arc Welding (GTAW)/ Tungsten Inert Gas (TIG)​

Gas Tungsten Arc Welding uses a non-consumable tungsten electrode in its welding process. Heliarc welding is another name to call GTAW.

This is a difficult welding procedure to learn, but it is very versatile to work with. Here, an arc is formed between the base metal/metals and the tungsten electrode. The electrode should not melt, but the arc creates a weld pool by contacting itself.

A thin wire, which is the filler metal, is then fed manually towards the weld pool to melt to form the weld. Welds can also be made without the filler weld material.

Shielding gas is required in the process of making an oxygen-free space. This is because of the sensitivity of tungsten to oxygen.

The inert shielding gas is fed using the torch, and it shields both the weld pool and the electrode. The welding output is free of slags and contaminants, creating excellent quality, precision welding.

The welder needs good skills and expertise to perform TIG welding. Steel, steel alloys, magnesium, nickel, titanium, brass, copper, and aluminum are some of the materials that use this welding technique.

The final work does not need an extra finishing job even most of the time. However, it is quite a slow process, yet, worth the time spent on the job.

Out of all the other welding processes, it is TIG that makes the strongest and finest welds. This welding process is typical to see in the industry as it delivers a finished job.

Industries like vehicle manufacturing, metal tool repairing, and tubing manufacturing get the use of TIG welding in their work.

Safety Precautions during Tungsten Inert Gas Welding​

Same as MIG welding, TIG welding too must be done with necessary safety precautions to do your job safely.

Welding arc emits UV and IR rays, which are harmful to eyesight and also can damage the welder’s skin. Shield gases can create breathing problems as they displace oxygen.

Unexpected electric shock can happen during the welding process. Molten metals emit toxic fumes, which also can create respiratory problems.

Below mentioned precautions are essential when performing TIG welding.​

• Use a welding helmet with the dark tinted window/ lens shade to protect eyes from harmful UV and IR. A good quality helmet will also protect the skin of the face and neck area from these harmful rays.
• Skin burns are possible due to the heat and rays emitted during the TIG welding. Too much UV rays on skin lead to skin cancer. To protect your skin, welding gloves, and long pants with long-sleeved shirts made of inflammable material are essential.
• Should NEVER do TIG welding during rain, and high-humidity surrounding. Sweating can also be dangerous. Water or wet skin can make an electric conductor that will give electric shocks. That is why; it is necessary to keep the clothing, boots, and gloves dry during the welding process.
• TIG emits welding fumes like ozone, nano-particles, and molten metal fumes. These can go through the respiratory system, creating serious respiratory diseases. The welding must be done in a well-ventilated area to protect yourself from this hazard.
• High levels of exposure to shield gases can displace oxygen, which will give headaches, dizziness, and nausea. This can even lead to unconscious deaths. Personal oxygen safety monitors or oxygen level depletion safety alarms will keep the welders and people around alarmed of this risk. It is also essential to use exhaust ventilation systems inside TIG welding factories.

Flux-Cored Arc Welding (FCAW)​

Flux-cored Arc Welding has been in the industry since the 1950s. It is developed as an alternative to stick or shield welding.

This welding process is quite similar to Gas Metal Arc Welding (GMAW) and Metal Inert Gas welding (MIG), yet different.

This FCAW process needs a tubular wire filled in flux. And, also depending on the filler, a shielding gas is not always needed for this welding process. It is a very cheap method and very easy to learn, as well.

Though it is cheap, there are some limitations to this method. The outcome of this method is not very pleasing or neat.

However, the equipment used for Flux-cored arc welding is portable, making it more convenient for different large scale projects. The welding process is fast too.

Ferrous metal welding commonly uses this type of welding process as it suits when high deposition rates are needed. The flux-cored arc is more manageable at high welding currents than other welding types.

The good visibility of the weld pool and the arc makes it easy for the welder to do his job fast and efficiently.

After finishing the weld, the slag coating on the weld bead must be removed to finish the work properly. The process emits some smoke and spatters as the filler material goes through the arc.

More about the FCAW process…​

This process can be either automatic or semi-automatic. The FCAW process, which does not use a shielding gas, is possible to use even during windy conditions, making it more attractive.

But, at the same time, that process creates more noxious smoke, which makes it inconvenient for the welder. It also requires more skill compared to the FCAW, which uses shielding gas.

The FCAW process, which uses shielding gas, is also known as dual shield welding among the welders.

Welders use an external supply to get the shielding gas. Welding structural steel is a major occasion where they use this process. It is also preferable in welding out-of-position metals and thicker metals.

This method, too, creates slag and is not very difficult to remove compared to the previously mentioned FCAW process. In a closed well-ventilated space, this process creates welds that have more consistent mechanical properties.

The welds have fewer defects compared to GMAW or SMAW, and the process is efficient too. However, the use of shielding gas creates some limitations at the same time.

Safety Precautions during Flux-Cored Arc Welding​

• Use a well-ventilated area to perform welding. Same as GSAW, the FCAW process also creates carbon dioxide and ozone when using shielding gas. Wear proper welding helmets to avoid inhaling toxic gases.
• Protective helmets should have auto-darkening lens shade to save eyesight from arc glare, UV rays, and sparks.
• Wear dark colored protective clothing to protect your skin from radiation and hot metal. Leather clothing provides excellent protection against burns.
• Base metals used for welding must be free from dirt and any chemicals. Chemicals make hazardous reactions when exposed to heat.
• Welding guns should be handled carefully. Touching it with wet or bare hands can give an electric shock. Always wear dry welding gloves throughout the welding process.
• As FCAW uses external shielding gas sources, handle them with extreme care. High-pressure gas cylinders can be deadly if handled carelessly.
• As FCAW creates lots of sparks, it is best to keep other people too away from those sparks. Use
• FCAW also creates lots of smoke. Therefore, keeping an effective fire extinguisher close by is always a good idea.

Summary​

Throughout this article, we get a proper understanding of the types of welding process. Though there are several dozens of welding processes, we can see only four types are in general.

They are as follows:

1. Arc Welding/ Shielded Metal Arc Welding (SMAW)
2. Gas Metal Arc Welding (GMAW)/ Metal Inert Gas Welding (MIG)
3. Gas Tungsten Arc Welding (GTAW)/ Tungsten Inert Gas (TIG)
4. Flux-Cored Arc Welding (FCAW)

All these processes have their own characteristics, advantages, and disadvantages. It is also crucial to follow relevant safety precautions while performing any type of welding.

Many deadly hazards can happen if welders ignore the proper protocol while doing their job. Learning welding from the basics is essential to become a skilled professional in the field.

Selecting the most appropriate welding process to suit the requirement is a must to achieve a job well done. Otherwise, there can be unnecessary extra costs, defects in the welds, and many disappointments from both welder’s and client’s ends.

Recommended reading:​

• Types of Welding Joints – 05 basic types and welding positions
• Best TIG welder for beginner | Top 11 Best Tig Welders Review 2020