Impression creep test of a P91 steel: a round robin programme

Abstract

The process of standardisation of small specimen creep testing techniques, specifically the impression creep test requires the repeatability of the test method. In this study it is accomplished through a round robin programme involving four different labs which have slightly different test set-ups adhering to predefined recommendations stated in previous work. The labs all conducted the same stepped stress test on a reference heat of grade 91 power plant steel and the displacement traces of the tests are analysed to outline the effects of different test set-ups and their efficacies. Main differences are in temperature control and loading application and control.

Keywords:

• Impression creep test
• P91
• round robin programme

Acknowledgments

The impression creep tests results reported here were produced by the four collaborating Laboratories: University of Nottingham, UK, Electric Power Research Institute, USA, VTT Technical Research Centre, Finland, and AMEC FW, UK. C. N. C. Dyson and W. Sun would like to acknowledge the support of BF2RA and EPRI, and S. J. Brett would like to acknowledge the support of EPRI via Agreement 10007317.