Welding Quality in Kenya: Application of Radiography

Welding Quality in Kenya: Application of Radiography

Michael M. GATARI1, John K. BIRIR1, David M. MAINA1, Stephen M. MUTULI2, Wilson M. KAIRU1.

1 Institute of Nuclear Science and Technology, College of Architecture and Engineering, University of Nairobi, P. O. Box 30197, Nairobi, Kenya, Phone: +254 20 318262, Fax: +254 (020) 2245566

Email: gatarimj@gmail.com, jbirir@gmail.com, dmaina@uonbi.ac.ke, kairuhwilson@yahoo.com

2Department of Mechanical and Manufacturing Engineering, College of Architecture and Engineering, University of Nairobi, Kenya.

E-mail: mutulis1@gmail.com

Introduction Methodology

Conclusion

Discussion

Results

References

• In this study radiography was used to assess the

quality of industrial welds and evaluation of

skills and competency of welders.

• Applications of welding include areas such as;

the construction industry, fabrication of

domestic products, repairs of machinery and in

transport industry.

The following samples were analyzed;

• 64 plate samples (3 mm thick) from the

informal sector across the country

• 92 plates (10 mm thick) and 18 pipes (8 mm

thick) from the formal sector.

• For all the acquired samples the field

investigators witnessed the welding processes

on site and performed visual inspection

before, during and after the welding process.

• The sizes of imperfections permitted by ASME

codes [2,3] were compared with the

dimensions of indications revealed by

radiographs.

• The type of discontinuities obtained were as

shown in the table and chart below;

• The percentage of samples with defects was

unacceptably high in both sectors investigated.

• Welders in the formal sector produced better

quality of welds as compared to informal sector

welders.

• This difference was attributed to the fact that

welders in the formal sector are subjected to

annual assessment, re-trainings, and make use of

welding procedures.

• Radiography was successfully used in

inspecting the quality of welding services in

Kenya.

• It revealed the wide deficiencies in the

quality of welds services given by the both

formal and informal sectors.

• Re-training of welders and annual assessment

through testing and licensing was found to be

an important aspect in the two sectors.

• The study also affirmed the importance of

radiography as an important tool in industrial

services/products inspection.

Acknowledgement• International Science Programme (ISP), University

of Uppsala, Sweden

• International Atomic Energy Agency (IAEA)

• University of Nairobi, Kenya

1. GOK Government of Kenya, “Economic survey,

2012”, Government press, 2012.

2. ASME Boiler and Pressure Vessel Code, “Section

VIII: Rules for Construction of Pressure Vessels”,

ASME press, USA, 2010.

3. ASME Boiler and Pressure Vessel Code, “Section

IX: Qualification standard for welding and

Brazing Procedures, Welders, Brazers, and

Welding and Brazing Operators”, ASME press,

USA, 2010.

• In Kenya, welding services are extensively

employed in both the formal and informal

sectors.

• Welding needs continue to increase with

increasing population, infrastructure and

vehicle fleet, and economic development.

• The Informal sector is an important sector as it

employs over 80 % of the working population

[1].

• The samples were subjected to further

examination by radiography.

0

20

40

60

80

100

Informal

Sector Plate

Welds

Formal Sector

Plate Welds

Formal Sector

Pipe Welds

Welds Type of Discontinuity Total

DiscontinuitiesUndercut Porosity Cracks (C) Lack of Fusion

(LOF)

Incomplete

Penetration (IP)

Informal

Sector Plate

Welds

16 % 6 % 3 % 34 % 33 % 92 %

Formal

Sector Plate

Welds

5 % 15 % 0 % 8 % 10 % 38 %

Formal

Sector Pipe

Welds

0 % 0 % 0 % 0 % 6 % 6 %

Note: The % indicated represents the percentage of total samples tested

having the given defect.

11th European Conference on Non-Destructive Testing (ECNDT 2014), October 6-10, 2014, Prague, Czech Republic