MIG Welding: Techniques, Advantages, and Applications

Understanding the Basics of MIG Welding Technique  

MIG welding technique is simple, easy, and economical. In this content, we will walk through the basics of MIG welding, how the technique works, and review the advantages and applications. 

Firstly, below are some technical terms to help you understand the concept better.  

Technical terms: 

MIG welding - Metal Inert Gas welding 

GMAW welding - Gas Metal Arc welding 

MAG welding - Metal Active Gas welding 

Base material – It is the material being welded, soldered, or brazed.  

What Is MIG Welding? 

MIG (Metal Inert Gas) welding also referred to as GMAW (Gas Metal Arc Welding) or MAG (Metal Active Gas) welding is an automatic or semi-automatic arc welding process. The welding process involves feeding a continuous and consumable wire electrode and shielding gas through a welding gun to weld the workpieces.  

MIG Welding Technique 

MIG welding is a versatile technique suitable for thick and thin section components. During the process, an electric arc melts the surface of the base materials (materials or workpieces to be welded) to form a weld pool which then cools to form a strong bond and join the metals.  

During welding, the welder continuously feeds a consumable heated wire electrode and shielding gas through a welding torch. To operate the welding process, the electrode wire is positively charged and connected to an electric power source for delivering a constant voltage. You can also use a constant current system and alternating current. 

To start the welding process, the wire electrode is brought in contact at the area of the workpieces where welding is to be done. This generates an electric arc between the tip of the electrode and the metal surface. The heat from the electric arc melts both the metal surface and the wire electrode to form a weld pool. The molten weld pool cools to form a strong weld joint. A shielding gas from the welding torch nozzle is fed alongside the electrode to protect the molten weld pool from moisture and airborne contaminants. The selection of shielding gas depends on the metal being welded and the application. During the welding process, the welder gradually moves the welding torch along the joint line of the welding area.  

The wire electrode can be solid or cored with its diameter ranging between 0.6 mm to 1.6mm. It serves both as a heat source (via electric arc at the contact tip) and filler metal for the welding joint. The wire melts and is used in the welding process making it a consumable electrode. During welding, the wire is fed through the torch’s contact tip (copper contact tube) which conducts welding current into the wire electrode.  

In semi-automatic MIG/MAG welding, the wire feeding rate and arc length are controlled by the power source. But the welder manually controls the wire position and travel speed. In automatic MIG/MAG welding no manual intervention is required to carry out the process.  

MIG Welding Advantages 

• MIG welding offers high productivity as the wire is continuously fed during the process. 
• When compared to TIG (Tungsten Inert Gas) or SMAW (Shielded Metal Arc Welding), MIG welding produces high-quality welds with faster speed.  
• MIG welding is a versatile process and can be easily used to weld various metals and alloys, including copper, aluminum, nickel, and iron.  
• The process can join dissimilar metals. 
• The shielding gas protects the arc and the metal transfers across the electric arc. As a result, there is only a minor loss of alloying elements.  
• The welding method produces minor weld splatter that can be easily removed.  

MIG Welding Disadvantages 

• High heat input and fluidity of the weld puddle make MIG welding unsuitable for overhead and vertical welding positions. 
• MIG welder equipment is complex in comparison to equipment used for shielded metal-arc welding.  

MIG Welding Application 

MIG welding is a versatile technique. This makes the process suitable across various industries for welding a broad range of structures, materials, and parts. MIG welding finds use in: 

• Sheet metal welding. 
• Home improvement, automobile, and automotive industry. 
• Fabrication work of pressure vessels and steel structures. 
• Heavy constructions such as building materials and bridges. 
• Welding of pipelines.  
• Repair of automotive. 

MIG welding is an automatic or semi-automatic arc welding process used to join pieces of metals together. It produces high-quality welds with faster speed. During welding, the welder uses a welding torch to continuously feed a consumable heated wire electrode and shielding gas. Being a versatile technique, MIG welding is suitable across various industries for welding a broad range of structures.