| dc.description.abstract | Welding is a joining method extensively used in fabrications and repairs of most metallic
items. In Kenya most of the repairs are done in the unregulated “Juakali” industry by the
manual shielded-metal-arc-welding technique. There is however a growing concern over the
safety of the “Juakali” works. Failures of many products such vehicle parts is blamed on
poor quality of weld joints and such failures may lead to fatal accidents and losses. In
general these kinds of failures have created a negative image of “Juakali” products/services
and hindered the growth of this vibrant informal industry. In this study, welding work by
various “Juakali” enterprises was sampled and analyzed. A total of 92 samples comprising
of repaired components and test coupons were collected from eight different locations across
Kenya namely Ngong, Dagoretti, Mlolongo, City-stadium, Kitale, Kisumu, Mombasa and
Meru. The welded joints were subjected to visual inspection, radiographic tests and tensile
tests to identify the kind of flaws present and their mode of failure. It was found that the
defects most prevalent in the 92 “Juakali” welds analyzed by visual and radiographic tests
were: Incomplete Penetration (41 % of the samples); Lack of Fusion (29 % of the samples);
Undercuts (12 % of the samples); Porosity (8 % of the samples) and Cracks (2 % of the
samples). From 124 samples subjected to tensile tests, 60 % of them fractured in the welds.
Additionally a total of 110 samples comprising of plate and pipe test coupons from the more
established SMEs were also subjected to visual and radiographic tests for purpose of
comparison. Defects found in SME samples were: Porosity (13 % of the samples);
Incomplete Penetration (9 % of the samples), Lack of Fusion (6 % of the samples), and
Undercuts (5 % of the samples). From this study it was concluded that the quality of welding
is very poor in Kenya especially in the “Juakali” Sector. This was observed to be a result of
incompetency and weak skills of artisans and technicians in the sector. Retraining was
therefore recommended to improve the knowledge and hands-on skills of the artisans and
technicians. Additional studies also need to be taken to determine other variables that may
have an impact on the quality of welding such as type of equipment, materials used experience of artisans and level of education. | en_US |
