Change of nonlinear acoustics in ASME grade 122 steel welded joint during creep

Abstract

Pipe inspection system by guide wave using a long distance waveguide AIP Conference Proceedings 1706, 140002 (2016) Abstract. In this paper, we described the changes of two nonlinear acoustic characterizations; resonant frequency shift and three-wave interaction, with electromagnetic acoustic resonance (EMAR) throughout the creep life in the welded joints of ASME Grade 122, one of high Cr ferritic heat resisting steels. EMAR was a combination of the resonant acoustic technique with a non-contact electromagnetic acoustic transducer (EMAT). These nonlinear acoustic parameters decreased from the start to 50% of creep life. After slightly increased, they rapidly increased from 80% of creep life to rupture. We interpreted these phenomena in terms of dislocation recovery, recrystallization, and restructuring related to the initiation and growth of creep void, with support from the SEM and TEM observation.

Detection of heterogeneous deposits on the surface of metal structures using nonlinear acoustic resonance technology

“…The microdamage and heterogeneous material can be considered an imperfect bond system that can cause the distortion of elastic waves. This distortion is responsible for the change in the observed resonance frequency in NAR tests, which can be described by the macroscopic nonlinear hysteretic behavior of the material [21,22].…”