This paper presents the results of investigations into the creep behaviour of a high Cr -Ni steel used in the petro-chemical industry. A programme of creep tests was established within a collaborative project, with the testing distributed between the two participating mechanical testing laboratories. Upon initial examination the test data and metallography of the raptured testpieces revealed inconsistencies between the two data sets, in terms of both creep behaviour and fractographic appearance. A detailed review was then initiated in order to identify the cause of this mis-match. Aspects examined included not only assessments of the instrumentation capabilities, calibration traceablility and operational procedures used by each laboratory, but also a thorough review of all of the metallographic evidence generated by the project from ruptured testpieces. Detailed consideration of this information led to the development of a model able to reconcile the two patterns of behaviour. This model, and details of its subsequent validation, are presented herein and conclusions are drawn as to the most appropriate testing practice for these materials.
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