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Shielded metal arc welding is a manual fusion welding process that widely used technique for
joining ferrous and nonferrous metals. The quality of this welding process determined by the
welding parameters includes electrode diameter, welding current, welding speed, arc length,
electrode angle, and welding positions. This type of welding machine is often used to weld low
carbon steel 0.01-0.034%of carbon contain up to 0.30%.This research was aimed to assess which
types of defects frequently occurred in small and medium enterprises understand how to control
the defects, how to improve welding skill and what identify reason or causes of those defects.
The objective of this thesis was determining the parameter affecting the Shielded metal Arc
welding and to identify the effect of welding defects to assess shielded metal arc welding defects
by Analyses the factor affecting or causing the SMAW defect on low alloy steel in small and
medium enter pries in the case of ADDIS ABABA city. About 180 target sample at one
enterprises total 900 sample were selected in 5 enterprise as random sample methods. Both
qualitative and quantitative research approach was used and prepared 50 questionnaires
distributed and collected. Data collection methods like observations, questionnaires,
photographic, interviews were presented. The collected data also analyzed and presented through
cause and effect or fish bone diagram, Pareto diagram and Control charts. Those were used to
determine which causes of a problem occur most frequently in each enterprise. Different causes
were introduced for those defects like lack of skill, using inappropriate welding, welding
environment. Due to this reason the main defects were Surface Porosity, Excessive Spatter and
Undercut were the main defect occurred in the SME‗s and maximum defects were happens
around 34.8%, 17.7% and 14% respectively and almost greater than 65% of the problems of
welding engaged in those defects.
Keywords: - SMAW, low carbon steel, SME‗s, defects, fish bone diagram, Pareto Chart |
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