What is Welding: Definitions, Different Types

One of the essential construction-related activities is welding. While other processes can bind materials together, this is the only one that can do so with metals. Most people are unaware that it now goes beyond that definition, even already capable of binding wood and plastic. Also, not many people know that it comes in different types.

Suppose you’re looking at becoming a welder. The good news is there’s currently a shortage in the industry of those who possess the skills we will describe below.

We’ll take you on an adventure to start learning some of the basics. We’ll also include links and references to other articles we have written that you may be interested in.

flux core welding

Welding Definition

For many, welding is defined as when two metals are joined together using extreme heat. Most people know this definition. They cannot distinguish it from other similar processes, namely soldering or brazing. That pressure alone or combined with heat can also melt materials.

Not many people know that it is limited to bonding the same material only. It means welding metal to metal is doable. Metal to steel or any other combination of varying base materials is impossible. The same material should be used to ensure a strong final product. Not doing so will permanently prevent the two materials from joining together, which is the goal.

Welding produces the strongest joints when the practitioner does it correctly. That is when the alternatives are soldering or brazing.

welder instructing a student

What is it?

In a nutshell, it involves bonding two-parent or base materials together of the same type. You use either heat or pressure, or even both. As a result, the two different parent materials end up becoming one. On the other hand, you can use a plasma cutter when you have a piece of metal you want to cut. We have written about how you can find the best one if you are more interested.

While it usually involves only the base materials, filler materials can also be added. Metal is added to the weld to strengthen the joint formed. Certain gases are used for shielding to prevent oxidation or contamination that can weaken the joint formed.

High heat is applied from a tool or machine, such as a blowtorch. It is used to melt a part or section of the base material to which the other one will be attached. It softens that area or creates a molten pool of material to which the material is attached. This pool or softened material is set to cool down. Once it resolidifies, the two are joined to form one material.

Pressure can also be used to bond them together. This pressure alone may be enough to bond the materials involved successfully. This pressure is used together with the heat generated by the pressure exerted over the base materials that need to be joined together.

welding helmet being put on a student

Different Types

Contrary to what most people think, welding is not just about combining a machine to combine two metals. There are different types present, which are listed below:

StickMetal Inert GasTungsten Inert GasFlux-Cored Arc
SubmergedElectroslagElectrogasAtomic Hydrogen
Carbon ArcEnergy BeamGasResistance
  • Stick – it is known as the Shielded Metal Arc Welding or SMAW. It is named as such because rods or sticks are essential. These rods consist of filler material that binds the metals and flux that aids in the binding process of the molten metals. At the same time, it protects them. Stick is considered the most popular in developing countries despite the weaker bond produced due to its low cost.

Stick is used in various applications and industries, such as construction and aerospace. It’s also used for shipbuilding and marine. You can also find it in petroleum, nuclear, field repair, or mining. It’s even used for structural welding and manufacturing despite its drawbacks.

  • Metal Inert Gas or MIG. It is the second most popular type. The Gas Metal Arc Welding or GMAW technique involves using a stick or gun. An electrode current-connected consumable wire passes through it. It forms an electric arc that produces enough heat to bond the materials while at the same time releasing a shielding gas. It has gained popularity due to its ease of use.

MIG is typically used in manufacturing and construction. It can also be found in automotive and other industrial processes. Check out our section on the various MIG welders you might be interested in.

  • Tungsten Inert Gas or TIG follows the same process as that of wire or MIG. It specifically involves using a non-consumable electrode containing Tungsten to create the required arc. TIG is now the most popular due to its ability to create a clean weld and high purity, which results in a superior result.

TIG is commonly used in doing repairs and creating art in the automotive and aerospace industries.

  • Flux-Cored Arc or FCAW – similar to MIG, but the wire used is a special tubular type containing flux.

FCAW is best for doing general repairs and manufacturing and shipbuilding. It has certain advantages making it favorable for underwater and pipeline projects.

  • Submerged Arc or SAW – while it also uses flux, it differs from the flux-cored arc because it occurs under a blanket of loose or granular flux. It results in fewer fumes and ultraviolet light, making it the safest type.

SAW is commonly used in industrial projects, especially in vessel and structural construction.

  • Electroslag – is typically used on thick metals that are non-ferrous. It involves melting flux to form a molten slag or pool, which an electric arc will pass through. The pool will eventually reach the electrode to extinguish the arc.

Electroslag is also typically used for the following purposes:

  • industrial purposes
  • castings
  • vessels
  • structures
  • ships
  • machinery
  • pressure vessels.
  • Electrogas share the same process as electroslag, but the electric arc present is deliberately left alone. The arc is known to be positioned vertically and allows the process to occur in a single pass.

Electrogas is best for:

  • constructing storage tanks
  • blast and chemical furnaces
  • vertical vessels
  • bridges
  • and ships.
  • Atomic Hydrogen, or AHW – is slowly becoming obsolete. It involves using two metal tungsten electrodes in an atmosphere containing hydrogen. It will cause the hydrogen to break apart and recombine, generating the needed heat.

AHW is suitable for any application where rapid processing is a must.

  • Carbon Arc or CAW is the first type of arc welding. The CAW technique uses a carbon electrode that is non-consumable to heat the metals together, eventually bonding them. It is also becoming obsolete.

CAW is suitable for copper use and repairing cast iron parts with bronze. It’s great for galvanized steel and thinner materials.

  • Energy Beam or EBW – involves placing the parent materials in a total vacuum and shooting a beam of electrons to those materials at high velocity. The electrons fired are converted to the heat needed to melt them and bond them together. It has two specific types available: electron beam and laser beam welding

EBW is used for various industries, including the ones below:

aerospaceresearchpower generation
oil and gasautomative

  • Gas – is best known as oxyacetylene or oxyfuel welding. Fuel gases are mixed with pure oxygen to adjust the temperature of the flame of a torch used for the bonding process. It is considered one of the oldest types of trade.

It is normally used in manufacturing, as well as in the aircraft and automotive industries.

  • Resistance – force is applied to both ends of the metal to be joined. An electric current is applied nearby to create the extreme heat required.

Various techniques of resistance include:

  • seam
  • spot
  • flash
  • upset
  • butt
  • and projection welding

It is best for industrial. It is also used for aerospace and automotive applications.

An arc is the most widely used in various industries among the different types used. Arc is a broad category that covers.

  • stick
  • MIG
  • TIG
  • flux-cored arc
  • submerged arc
  • electro slag
  • electro gas
  • atomic hydrogen
  • and carbon arc welding

It is used in various industries. All these require electricity to generate the arc required for the bonding process.

Not many people know that it can also be done underwater, but only for specific types. Hyperbaric is a specialized option that can be done via either wet or dry welding. Wet welding often uses the stick type, with the bubbles produced by the flux acting. They shield to prevent the electrocution of the craftsman. On the other hand, dry welding involves creating a hyperbaric chamber surrounding the area before following the chosen type.

welder welding inside a building


Aside from choosing what type to use, craftsmen also choose the available processes. They’ll have to determine which one is most suitable for their project. Which process to choose depends on the joint and the material being joined together. There are various welding joints, including edge and corner. Specific joints warrant an article of their own.picture of a welder

Cold pressure Explosive Friction Inertial 
Induction Percussion Ultrasonic  

The processes available are broadly categorized into two: fusion and pressure.

Fusion is the process many are familiar with since it involves heat to bond materials together. The edges of the parent material are heated. They are already joined when they cool down and harden. Using filler material and inert gases is optional, and no pressure is needed to bond them together. The different types mentioned above fall under fusion.

Fusion requires at least one of the parent materials to have a solid-state solubility. It’s what determines their weldability. Suppose the parent material is non-soluble in the solid-state. It will require a soluble material for the process to be possible.

On the other hand, the pressure technique involves using external pressure to join the joints. These joints are produced through solid-state welding. It involves adding pressure at temperatures below the melting points. A fusion state requires doing so at above melting point temperatures.

Unlike fusion, pressure requires that the joints or ends of the material are free of contaminants. Common contaminants are oxides and films that are non-metallic. These joints should be completely clean to ensure that the joint made between the materials is the strongest possible.

Welder at construction site

Pressure welding is used when the materials involved are ductile or whose ductility increases as the temperature increases. Some examples are:

  • Cold pressure – joins materials, specifically for electric components and wires. It’s also used for metal sheets without requiring heat to do so.
  • Explosive – necessary if the parent materials are dissimilar metals whose joints require welding, such as for cladding. This solid-state process involves using explosives to bond materials together. These explosives cause one of the materials to accelerate toward the other and weld them together.
  • Friction – two metals are rubbed together, and the friction between them generates the heat needed. It is also suitable for dissimilar metals, but it can also be used for similar ones.
  • Inertial – similar to the friction technique, but it involves rotating one of the materials to the other. The latter remains stationary. It is ideal for alloys with high strength.
  • Induction is mostly used for pipes and tubes. It involves using an induction coil that electromagnetically produces the heat required. The tube or pipes involved passing through the coil at high speeds. It causes heating on its edges and is squeezed together to form a seam that joins them together.
  • Percussion – involves using quick electrical discharges to form an arc with a high temperature. This discharge causes pressure to be applied to the materials involved, bonding them together. It is also suitable for joining dissimilar metals.
  • Ultrasonic – vibrations are produced through sound waves at high frequency, and these cause the materials to bond together. It is normally used for thin sheets and plastics.

Choosing the right piece of equipment

Welder working inside

It’s a wild world out there. Maybe you’re at the early stages of choosing the welder that will get done you are hoping for. We want to start preparing you for the process.

You may not necessarily have an initial need for an engine-driven welder. There is a chance you may want one of those days. If you are just getting started, it may be hard to justify going out and spending $4,000 to $6,000. They are also a lot of power for most businesses.

Engine-driven welders have a time and a place. Some craftsmen are making extremely impressive metalwork with some of these machines. It’s like saying that you need to go out and spend more than $10,000 to buy a portable sawmill because you have a couple of trees in the backyard.

Is that really what you want to do? Would you rather find the piece of equipment that may be appropriate to your level?

There’s a bunch of different equipment available on our platform. Take a look at other platforms and figure out your needs. You need to feel confident starting the process. You may already have a price point that you don’t want to go over. If that is the case, we can recommend a piece of equipment that works for that price point!

If you are trying to stay cost-conscious, don’t just go online and find the cheapest piece of equipment. It will be a nightmare to work with. We encourage you to buy something that has been mildly used before.

Welder in the middle of a weld

What to start looking for

There are different processes you can choose from. Each welding technique has its advantages and disadvantages to consider. You need to figure out which technique you want to get started with. The first piece of equipment you buy will likely be tailored only to provide that one type of process.

If you are just getting started and want something relatively easy to learn without a big need, all the welds must be perfect. Of the highest quality, we’d probably recommend that you get started with MIG. If you are more ambitious, skip that step and go straight to TIG.


You will need to know the type of work you need to do. It will guide the welding equipment you are looking for and the process you should be doing. There are better and worse processes for each type. The auto body repair work is the thinnest type of metal you will likely be working on. In contrast, hunting stands and utility trailers require significantly more power.

Look for equipment that can provide you with the power level to weld the surfaces you are looking to work on. You don’t want to have great aspirations for doing some really serious work. You are left with a welder who does not have the chance to provide you with the power you need. The thicker the type of surface you’ll be working with, the higher the current will also need to be.

Be sure to check out the machine’s duty cycle. It indicates whether you are currently looking at a cheap piece of machinery or not. Suppose you are looking to do body repair work occasionally. You probably don’t need an extravagant machine with a high-duty cycle. You will still want something that won’t drive you crazy to use.

worker at construction site


What is welding in simple words?

Welding is fusing two or more parts together. It’s done either by applying heat, pressure or sometimes even both. Typically, parts of the same material are bound together.

What do welders do?

Welders help build or mend products using a combination of heat and pressure to fuse materials.

What are the 7 basic types of welding?

Some of the most basic types of welding include:
1- MIG, also known as Gas Metal Arc Welding (GMAW)
2- Energy Beam Welding (EBW)
3- Stick, also known as Shielded Metal Arch Welding (SMAW)
4- Flux, also known as Cored Arc Welding (FCAW)
5- TIG, also known as Gas Tungsten Arc Welding (GTAW)
6- Plasma Arc
7- Atomic Hydrogen Welding (AHW)

What is happening when you weld?

If two pieces are welded together using heat, a section of each piece is warmed up. As the sections melt, they’re attached to each other and allowed to cool down.

Pressure is used for welding the pieces together. The materials are laid on top of each other when they’re to be joined. The welder then applies mechanical strain, which forces the pieces together.

What is the strongest weld pattern?

TIG Welding is the strongest type. It’s also referred to as Gas Tungsten Arc Welding (GTAW).

Time needed: 15 minutes.

how to choose what kind of welder you need

  1. Figure out the type of metal you will be welding.

  2. Determine the current range that works for your material’s thickness.

  3. Establish the power supply that your setup offers.

  4. Take into account any environmental factors that may interfere with your setup.

Final note

Did this article on the topic help give you a better understanding of the process? Do you still have questions regarding the various types? We have also written an article on using a plasma cutter on metalwork. Maybe you don’t know where to continue from here. Consider reading about the differences between the two most common types with our MIG vs. TIG article.

We’re on a mission to provide users with the best content for professional services like welding. That’s why we are continuously expanding our offering. Are you curious to learn more? You can dive into our article on the best plasma cutters. Take a closer look at some of the popular options on the market. Suppose you save this platform somewhere convenient and visit again next month. We’ll probably also have posted many new articles that might interest you, like this one on low-maintenance dwarf shrubs.