The document summarizes the development of gas metal arc welding (GMAW). It discusses how GMAW was developed in the 1940s using an aluminum electrode and argon gas shielding. In the 1950s, carbon dioxide was used as a welding atmosphere. The short-arc variation of GMAW was developed in the late 1950s, which increased versatility and allowed welding of thinner materials. The document also covers GMAW equipment, variables that affect weld quality like current and wire feed speed, and safety precautions for GMAW.

1. MIG/MAG WELDING
Shivank Shah

2. Development of GMAW
Humphry Davis discovered the electric arc in 1800s
Metal electrodes invented by N.G. Slavianoff and C. L. Coffin late 1800’s
In 1920 early predecessor of GMAW was invented by P. O. Nobel of General Electric with no shielding gas
GMAW was developed by the Batelle Memorial Institute in 1948.
smaller diameter electrode developed by H. E. Kennedy.
The process relied on an aluminum continuous fed electrode.
Shielding was with argon gas.
Advantages: Good deposition rate ,Disadvantage:High cost of inert gas
In 1953, the use of carbon dioxide as a welding atmosphere was developed by Novoshilov and Lyubavshkii
In 1958 and 1959, the short-arc variation of GMAW was released, which increased welding versatility and made
the welding of thin materials possible while relying on smaller electrode wires and more advanced power
supplies. It quickly became the most popular GMAW variation.

3. Types of GMAW Welding

4. Advantages of 100% CO2 Welding
• Easily Available
• Least expensive
• Deep weld penetration.
• Fast deposition rates.
• Can be easily adopted for semi-automatic and automatic use.
Disadvantages of 100% CO2 Welding
• Less stable arc.
• More spatter.
• Limited to short –circuit mode of metal transfer.

5. GMAW EQUIPMENT AND SETUP

6. Mechanism of Spray Transfer

7. Variables affecting Quality of weld
• Weld Current and wire feed speed

8. Variables affecting Quality of weld (cont.)
• Electrode Extension and Contact Tip to Work Distance

9. Variables affecting Quality of weld (cont.)
• Welding Voltage
• Travel Speed

10. Variables affecting Quality of weld (cont.)
• Properties of Wire : (Geometrical and Chemical) : In Mahindra :ER70S-G (Uniweld)
Suitable for welding steels with moderate rust and contamination
• Gas flow rate

11. GMAW Troubleshooting
• POROSITY :
• Reasons: Inadequate shielding gas, moisture,spatter in nozzle

12. GMAW Troubleshooting
• Incomplete Joint Penetration (Lack of Penetration)
• Burn Through

13. Welding Safety Measures : PPE
• Some safety equipment such as leather apron, UV shielding helmet, goggles and welding gloves.

14. Sources:
• http://www.gowelding.org
• http://www.bernardwelds.com/mig-welding-shielding- gas-basics-p152080#.VlQ31fmqqko
• http://www.weldersuniverse.com/MIG_wire.html
• www.weldguru.com
• www.weldability.com
• www.lincolnelectric.com

15. THANK YOU !!