Metal inert gas (mig) welding

One of the welding processes that used in Engineering field is the metal inert gas welding. There are several types of welding processes similar to this, but MIG welding has its unique features.
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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.

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

9. 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

10. 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