• Holdsworth, S. R.
• Auerkari, Pertti
• Hurst, R. C.
• Rantala, Juhani

Abstract

The prediction of long-term high-temperature materialproperties isdifficult when the prediction is based onnormal short to medium-termuniaxial creep test results.The test acceleration achieved by increasingeither testtemperature or stress or both, easily leads todeformationmechanism changes, which makes the predictionunreliable. In a short-termuniaxial laboratory test itis impossible to produce the same type of creepdamage asobserved in power plant components which have been inoperationfor more than 100 000 hours.An alternative method has been proposed based onusingmultiaxial test specimens. This concept was tested in theLICONproject (BE95-3019, 1996-2001), where thetheoretical basis of the method wasdeveloped andverified experimentally for three steels in base materialandwelded condition by using several differentmultiaxial laboratory specimensand full-size testcomponents. A typical test campaigne required to applythe methodology is a series of creep crack growth testson standard CTspecimens to 0.5 mm crack extension andtest durations between 1.000 and10.000 hours. Acomprehensive Code of Practice document was produced intheproject, and this will be published later in 2007.

Topics

• impedance spectroscopy
• crack
• steel
• deformation mechanism
• creep
• creep test