Manual Metal Arc Welding (MMA) & Gas Metal Arc Welding (GMAW)
Date Submitted: 09/29/2003 04:10:45
Introduction:
Manual metal arc welding was first invented in Russia in 1888. It involved a bare metal rod with no flux coating to give a protective gas shield. The development of coated electrodes did not occur until the early 1900s when the Kjellberg process was invented in Sweden and the Quasi-arc method was invented in the UK. But the coated electrodes used these days were slow to be adopted because of their high cost. But because
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between short circuiting giving hotter welding.
Advantages:
1- Good manual application
2- Capable of a high degree of mechanisation
3- Applicable to most coppers and copper-based alloys
4- Good mechanical joint properties
5- No flux requirements
6- Heat affected zone can be localised
7- Low distortion when properly controlled
8- Low cost filler metals
Disadvantages:
1- Fusion of parent metals may create metallurgical problems and porosity in joint.
2- High degree of manual skill required.
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