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 !!