The Significance of the Radiography Technique in the Non-Destructive Evaluation of the Integrity and Reliability of Cast Interconnects
Significant changes in oil and gas drilling have
emphasized the need to verify the integrity and reliability of drill
stem components. Defects are inevitable in cast components,
regardless of application; but if these defects go undetected, any
severe defect could cause down-hole failure.
One such defect is shrinkage porosity. Castings with lower level
shrinkage porosity (CB levels 1 and 2) have scattered pores and do
not occupy large volumes; so pressure testing and helium leak testing
(HLT) are sufficient for qualifying the castings. However, castings
with shrinkage porosity of CB level 3 and higher, behave erratically
under pressure testing and HLT making these techniques insufficient
for evaluating the castings- integrity.
This paper presents a case study to highlight how the radiography
technique is much more effective than pressure testing and HLT.
 International Atomic Energy Agency, "Guidebook on non-destructive
testing of concrete structures", Vienna 2002.
 Kent Carlson, "Analysis of ASTM X-Ray shrinkage rating for steel
castings", Int. J. Cast Metals Res., vol. 14, pp. 169-183, 2001.
 American Society for Testing of Materials, ASTM E446 -10, "Standard
Reference Radiographs for Steel Castings Up to 2 in (50.8mm) in
Thickness", Annual book of ASTM standards 2010 (03.03).
 MIL-STD-2175A, 25th August 1993, "Military standard: Castings,
Classification and Inspection".
 American Society for Testing of Materials ASTM E1742 /E1742M,
"Standard Practice for Radiography Examination", Annual book of
ASTM standards 2011 (03.03).