MIG welding, also known as gas metal arc welding, is a semiautomatic welding process where a continuous wire electrode is fed through a gun and melts upon contact with the base metal. Shielding gas protects the weld from atmospheric contamination. MIG welding is commonly used in manufacturing applications like automotive repair and pipe welding due to its high deposition rate, ability to produce quality welds quickly, and versatility in welding many metal alloys. However, it is limited to flat and horizontal welding positions due to issues with high heat input and weld puddle fluidity in vertical and overhead positions.

1. Metal Inert Gas (MIG) Welding

2. Contents
• What is MIG welding?
• MIG Welding process
• Schematic Representation of MIG Welding
• Applications of MIG Welding in Manufacturing
• Advantages of MIG Welding
• Disadvantages of MIG Welding

3. What is MIG Welding ?
• It is also known as Gas Metal Arc Welding.
• It is a high- deposition rate welding process.
• The metal wire is fed from a spool.
• This is a semiautomatic welding process.

4. MIG Welding Process
• Consists of a handle with trigger control to wire feed the spool to the weld
joint.
• MIG basically requires:
- Electricity to produce heat.
- An electrode to fill the joint.
-Shielding gas to protect the weld.

5. MIG Process contd..

6. Schematic Representation of MIG Welding

7. Welding Variables and Parameters
• Electrode extension
• Wire feed speed - amperage. Controls fusion and penetration.
• Travel speed - controls depth of penetration.
• Gas flow rate - protects weld from atmosphere.
• Voltage - set on the welding machine and controls the arc length.
• Tilt angle - back or fore hand should be not greater than 15° from the
perpendicular.

9. Applications of MIG in Manufacturing
• Automotive repair
• Overlay of resistant coating
• Welding pipes
• Rebuilding equipment
• Reinforce the surface of worn out railroad track.

10. Advantages of MIG Welding
• High quality welds can be produced much faster
• Since a flux is not used, there is no chance for the entrapment of slag in the
weld metal resulting in high quality welds
• The gas shield protects the arc so that there is very little loss of alloying
elements. Only minor weld spatter is produced
• MIG welding is versatile and can be used with a wide variety of metals and
alloys
• The MIG process can be operated several ways, including semi and fully
automatic

11. Disadvantages of MIG Welding
• Cannot be used in the vertical or overhead welding positions because of the
high heat input and the fluidity of the weld puddle
• The equipment is complex