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MIG/MAG WELDING
Shivank Shah
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.
Types of GMAW Welding
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.
GMAW EQUIPMENT AND SETUP
Mechanism of Spray Transfer
Variables affecting Quality of weld
• Weld Current and wire feed speed
Variables affecting Quality of weld (cont.)
• Electrode Extension and Contact Tip to Work Distance
Variables affecting Quality of weld (cont.)
• Welding Voltage• Travel Speed
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
GMAW Troubleshooting
• POROSITY :
• Reasons: Inadequate shielding gas, moisture,spatter in nozzle
GMAW Troubleshooting
• Incomplete Joint Penetration (Lack of Penetration)• Burn Through
Welding Safety Measures : PPE
• Some safety equipment such as leather apron, UV shielding helmet, goggles and welding gloves.
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
THANK YOU !!
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