Evaluation of Wires and Testing Methodology for MAG Welding
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Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Publicerad
2012
Författare
Salama, Ahmad
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
In this project a methodology for testing MAG wires was conducted. The method involves the use of some advanced technologies like a high speed camera and a high frequency data logging devise to capture the welding starting properties, in which six wires both copper and bare were selected for the tests, while setting most parameters such as work piece material, power source, voltage, current and wire feed speed as constants. The main purpose is to evaluate the High Speed Camera usage as a non-real-time sensor for the suggested method. At the mean time a comparison was established between the selected wires, entailing their coating, type of arc used, welder’s opinions on performance, integrity of solidified weld among others. This project was divided into 3 tasks, the first task was recording welding tests using the high speed camera, the second task involved testing the wires manually with experienced welders to compare their subjective opinion to the data collected from the first task, and finally the third task was a comparison of the filet weld size of the same six wires, thus reflecting weld integrity. Using the method of high speed camera and data logger shed some light on several features and introduced fresh new aspects that were not possible to attain otherwise such as the time to establish a stable arc for each wire and its dependence on wire cuts and type of arc used, while comparisons between wires showed how wire composition, coating type and arc applied affect welding starting properties and voltage/current trends. It was concluded that the unstable arc duration is prolonged in case of the presence of wire-cuts or solidified droplets on wire tips and that copper-coated wires have fewer spatter and non-spherical shaped droplets compared to bare wires. Finally, it was also proven that weld bead integrity and flatness increases with increasing applied voltage.
Beskrivning
Ämne/nyckelord
Övrig bearbetning/sammanfogning , Konstruktionsmaterial , Materialvetenskap , Produktion , Other processing/assembly , Construction materials , Materials Science , Production