Experience with Small Punch (SP) Creep Testing at the JRC since the launch of the CEN Code of Practice

This paper first describes the key aspects of the European Code of Practice for SP creep testing and then illustrates its application to the testing of a wide range of steels. The precursor testing which actually led to the launch of the Code, concentrated on 1CrMoV rotor steel and a round robin testing programme was shared between four cooperating laboratories. The results served in the formulation of the Code itself including the first analytical relationships concerning the stresses operating in the SP test. The next alloy to be studied at JRC was the 2¼Cr1MoV modified steel, widely used in petro-refinery components to resist hydrogen attack. Indeed the strong resistance to hydrogen damage caused the study to concentrate on thermal ageing effects. Subsequently testing concentrated on the power plant alloy, 9Cr1Mo, and in particular the zones of its weldments, known for their susceptibility to cracking in service. After remanent lifetime estimation and special location studies, a third application of the SP creep test would be for studying materials as they are being developed when only available in limited quantities. Finally an ODS steel, exhibiting particularly anisotropic creep properties was selected as a forerunner in demonstrating the effectiveness of SP testing for more exotic development alloys. The use of different alloys in the programme facilitates a better understanding of the crucially important relationship between the load in the SP creep test and the equivalent stress in a uniaxial creep test.

HURST Roger Christopher;  TURBA Krystof;  BLAGOEVA Darina;  HAEHNER Peter; 

2013-02-28

The Japan Institute of Metals

JRC72984

978-4-88903-407-3,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC72984,