welding play a pivotal role in a wide range of industries, from construction to manufacturing. Understanding the different types of welding processes is crucial to selecting the right technique for a particular application. In this article, we will explore the two most common welding methods: MIG (metal inert gas) welding and TIG (tungsten inert gas) welding, highlighting their characteristics, differences and applications.

MIG welding

What is MIG welding?

MIG welding, also known as gas metal arc welding (GMAW), uses a consumable wire electrode that is continuously fed through the welding torch. The process also uses a shielding gas to protect the weld area from atmospheric contamination. MIG welding is known for its speed and efficiency, making it a popular choice for a wide range of applications.

Key features of MIG welding

1. Electrode: MIG welding uses a consumable metal wire electrode that acts as both the electrode and filler material.
2. Shielding gas: Argon is commonly used, and in some applications is often mixed with carbon dioxide, making it suitable for welding non-ferrous metals and high-strength steels.
3. Applications: MIG welding is ideal for thick metals and is commonly used in manufacturing, construction and automotive repair.

Advantages

1.Speed: Faster than many other welding processes, for greater productivity.
2.Easy to use: MIG welding is relatively easy to learn and operate, and can be used by beginners and professionals alike.
3.Versatile: It can be used on a wide range of metals, including steel, aluminum and copper.

Disadvantages

1. Welding quality: Despite its high strength, MIG welding may not be as aesthetically pleasing as TIG welding.
2. Control: Compared to TIG welding, it has less precise control over the weld, which may affect the welding quality.
3. Fumes: The process produces more fumes, so proper ventilation is required.

Stick (STICK)

welding (SMAW) is a welding method in which an electric arc is established between a coated electrode and the base material to be welded. The electrode is covered with flux, which melts when heated and has the functions of stabilizing the arc, forming slag, deoxidizing and refining.

Welding principle diagram for stick (STICK) welding

The welding power source uses an alternating current welder or direct current arc welder with a falling characteristic. Generally, an alternating current arc welder is used, and a direct current arc welder is used when arc stability is particularly required.

Main features:

Simple welding operation. The welding clamp is light and easy to move, and is suitable for a wide range of applications.

MIG/MAG welding (CO2/MAG/MIG)

Gas Metal Arc Welding (GMAW)
MAG welding: metal Active Gas Welding (Active Gas: active gas)
MIG welding: metal Inert Gas Welding (Inert Gas: inert gas)

They are broadly divided into MAG welding and MIG welding according to the type of shielding gas. MAG welding uses CO2, or CO2 mixed with oxygen in argon (these are called active gases). Welding using only CO2 gas is customarily referred to as CO2 arc welding, to distinguish it from MIG welding. MIG welding uses inert gases such as argon and helium. The principle is as follows: an electric arc is generated between a thin consumable electrode (welding wire) and the base material, and the surrounding area is sealed with a shielding gas. This method of welding melts the base material and the welding wire. It is widely used in semi-automatic welding, where the operator holds the welding torch, as well as in robotic and automatic welding.

Schematic diagram of consumable electrode gas shielded welding

Features of CO2 welding: 

Fast welding speed High ignition efficiency Deep weld pool High deposition efficiency One type of welding wire can be used for a wide range of plate thicknesses Good weld quality Low distortion after welding One type of welding wire can be used for a wide range of base materials.

MIG and MAG welding

It should be noted that MIG welding is often compared with MAG (metal active gas) welding. The main difference between the two is the shielding gas used. MIG mainly uses inert gases such as argon, which is suitable for welding non-ferrous metals; while MAG uses active gases such as carbon dioxide or a mixture of argon and carbon dioxide, which is more suitable for welding high-strength steel.

TIG welding

What is TIG welding?

TIG welding, or gas tungsten arc welding (GTAW), uses a non-consumable tungsten electrode. A separate filler wire is used to add material to the weld, which allows for greater precision and control. This method is particularly suitable for applications where high-quality welds are required.

Key features of TIG welding

1. Electrode: TIG welding uses a non-consumable tungsten electrode.
2. Shielding gas: Argon is the most common shielding gas, but helium or argon-helium mixtures can also be used.
3. Applications: TIG welding is ideal for thin metals and is widely used in industries such as aerospace, automotive and medical device manufacturing.

Advantages:

1. Precision: High precision and control, ideal for complex designs and thin materials.
2. Quality: Cleaner, more aesthetic welds with fewer defects.
3. Versatility: Can weld almost all industrial metals and alloys, including stainless steel and titanium.

Disadvantages:

1. Speed: TIG welding is generally slower than MIG welding, which can increase labour costs on large projects.
2. Skill level: Requires more skill and experience to achieve the best results.
3. Cost: higher equipment and maintenance costs compared to MIG welding.

TIG welding techniques

DC TIG: uses direct current and is suitable for welding materials such as stainless steel and copper.
AC TIG: uses alternating current and is suitable for welding aluminum and magnesium because of its cleaning effect, which removes the oxide layer from the surface.

AC TIG welding schematic diagram

MIG vs TIG welding compared

Electrode and filler material

MIG welding: consumable welding wire electrode that also acts as the filler material.
TIG welding: non-consumable tungsten electrode and separate filler wire.

Welding speed and efficiency

MIG welding: faster and more efficient, suitable for high-volume production environments.
TIG welding: slower but more precise and of higher quality, suitable for delicate and complex work.

Welding quality and aesthetics

MIG welding: high welding strength, but not as aesthetically pleasing as TIG welding.
TIG welding: renowned for its high welding quality, aesthetics and low defect rate.

Application

MIG welding: best for thick metals and large projects, commonly used in construction and manufacturing.
TIG welding: suitable for thin metals and applications requiring high precision, such as aerospace and medical equipment.

Cost and maintenance

MIG welding: generally more cost-effective in terms of equipment and operating costs.
TIG welding: higher equipment and operating costs due to the level of skill required and the precision it provides.

Conclusion

MIG vs TIG welding each have their own unique advantages and are suitable for different applications. MIG welding is fast and easy to use, and is ideal for large projects and thick metals. TIG welding, on the other hand, offers greater precision and quality, and is the preferred method for thin metals and applications that require fine workmanship. Understanding these differences will allow you to make an informed decision based on your project requirements and budget.

In addition to MIG vs TIG, there are other welding methods worth mentioning, such as SMAW and resistance welding, each with their own specific applications and characteristics. Ultimately, the choice of welding technique depends on the materials involved, the strength and appearance required, and the specific requirements of the project at hand.