Welding Processes and Types: MIG, TIG, and Spot Welding


Welding Processes – An Overview

Welding is a fabrication process that joins materials, usually metals and thermoplastics, into one. It is different from gluing, brazing, and soldering as these processes only sticks two separate pieces of materials, while in welding two or more separate pieces of materials are actually turned into a single piece.

Welding jobs are done either by fusion welding in which materials are first made liquid and then solidify together, or by solid-state welding in which materials are joined together by forcing them together with a lot of pressure and sometimes heat.

Fusion Welding Processes and Arc Welding

The most popular type of welding is fusion welding. It relies on melting to join materials of similar compositions and melting points. The most obvious way to get a material into liquid state is to heat it up and melt it but you can also use solvents such as acetylene and mix it with oxygen to produce an intense amount of energy required for melting the metals. Using oxygen and acetylene to weld in this way is called the Oxy-Gas Welding or OFW method.

Using electricity is another way to melt a metal. The most common type of welding that uses electricity for melting is called Arc Welding. Arc welding uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. With arc welding, there is a flexibility of using either direct current (DC), or alternate current (AC), and they can also be done using consumable or non-consumable electrodes.

The two most popular types of arc welding are Gas Metal Arc Welding (GMAW), usually called MIG, and Gas Tungsten Arc Welding (GTAW), usually called TIG.

The Most Popular Types of Welding Processes – Their Advantages and Disadvantages

Melting metals can be done in many different ways but in order to make an educated decision, it comes down to picking the right welding technique for the welding job. Today, many welding processes can be done by automated equipment; however some projects require a manual touch to give the material the right shape and strength.

Here is a list of the most popular welding methods that belong to the family of fusion/arc welding processes with their set of advantages and disadvantages to help you pick the right one to get your job done:

Gas Metal Arc Welding (GMAW) or MIG: Gas Metal Arc Welding, also known as metal inert gas or MIG welding, is an automatic or semi-automatic process that uses a continuous wire feed as an electrode and an inert or semi-inert gas mixture to protect the weld from contamination. Because a wire electrode melts as it’s being used, MIG is called a consumable electrode process.


  • The continuously fed wire electrode keeps both hands free, which improves the welding speed, quality of weld, and the overall control.

  • Provides better weld pool visibility.

  • Using a shielding gas protects the arc by allowing a very little loss of alloying elements as the metal transfers across the arc.

  • Can weld a wide variety of metals and alloys, while operating at a variety of semi and fully automatic ways.


  • They are complex and costly. Shielding gas, electrodes, and replacement tips and nozzles can add to the expense.

  • Using them outside can expose the shielding gas to the havoc of the wind that can harm the purity of the weld.

  • The bottle of shielding gas can take time to replace and can get in the way while welding.

Gas Tungsten Arc Welding (GTAW) or TIG: Gas Tungsten Arc Welding (GTAW), also known as tungsten inert gas (TIG) welding, uses non-consumable tungsten as electrode. The inert or semi-inert gas mixture along with a separate filler material makes use the heat produced by the tungsten electrode to melt the base metal. As this method requires stable arc and high quality welds, they are especially useful for welding thin materials.


  • It offers a solution for welding critical joints or for situations where small or exceptional precision is required.

  • Can be done with wide variety of metals that produce a high-quality and high-purity weld.

  • The price is comparatively reasonable.


  • Can be performed on only clean metals. Welding dirty metals will result in a weaker weld quality.

  • It has a low deposition rate which means you can’t TIG weld things quickly.

  • It’s difficult with TIG welding to take apart two products that have been welded together without destroying each component.

  • Generally restricted to flat or horizontal welding.

Production Spot Welding: Production spot welding is a popular resistance welding method used to join overlapping metal sheets of up to 3 mm thick. In this process, metal sheets to be welded are held together under pressure by electrodes. When a current is applied, the resistance at the interface of sheets causes coalescence only at the contact point (spot) and affects a weld. Its applications are extensive in automotive industry.


  • It consumes very less energy when compared to other welding methods.

  • Limited work piece of deformation.

  • High production rates.

  • Easy automation.

  • No requirement of filler materials.


  • Weld strength is significantly lower.
  • The size and shapes of the electrodes determines the size and strength of the weld.
  • If the current isn’t hot and strong enough, or the metal is not held together with strong force, the spot weld may become weak.
  • The appearance of the join is often rather ugly, and there can be cracks.

Continental Industries based in Anaheim is a prominent name in MIG, TIG, and production spot welding. For more information about our services, call us at (714) 632-9190.

Continental Industries is a precision sheet metal fabrication company. We have more than three decades of experience in providing world class design, engineering, prototyping and fabrication services to customers in Southern California. Our constant and sincere effort has been to provide excellent support & satisfaction to our customers. We promise quality and our versatile experience speaks through the perfection in our work.

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