Manual Metal Arc Welding (MMA) & Gas Metal Arc Welding (GMAW)

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 …showed first 75 words of 2419 total…

…showed last 75 words of 2419 total…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.