LITERATURE REVIEW-4A

The cross - correlation of eddy current images for detection of fatigue crack propagation by MOORE and others (2001), directs that there is a need within the NDE industry to calculate the growth of damage such as fatigue cracking and corrosion over the life of a structure. Charpy impact testing was performed to determine impact test and properties as a function of temperature,in one case to verify the compliance with requirement and in other case,as part of a temper embitterment assessment. Fracture toughness crack tip opening displacement (CTOD) testing was performed to obtain the fracture toughness required in the assessment. In the remaining cases the small samples were used to obtained tensile testing specimens and to perform direct metallographic evaluation to determine the nature and extent of the degradation that the steel suffered during service.A total of twelve half size Charpy specimens were machine from the samples that were extracted. Since these samples were small to carryout the Charpy impact tests, extension taps were welded to the end of the test materials where the v-notch was machined. The absorbed energy and the transmission temperature depend on the size of the Charpy specimen and since half size specimen were used, the correlation by API RP 579 was used. For half size specimen for the absorbed energy conversion of full size was achieved by multiplying by two. The procedure is to determined the transmission temperature and then add 11oC
(12oF) to account for the temperature shift in using half size specimens. The impact results at -12oC and -1oC (10oF and 30oF) are shown in figure 2.