Dynamics of Hydrogen Induced Blistering of a Low Carbon Steel Sheet by Lamb Waves Analysis

摘要

With the aim of studying the fracture dynamics ofenvironmentally assisted fractures in thin pates. We developed anew source simulation method of the zeroth-order symmetric (orS0-) Lamb wave using the experimental overall-transfer functionof the system. The transfer function was determined by the time-domain deconvolution of detected S0-Lamb component by theartificial fracture source of a compression-type PZT elementwhose vibration kinetics was previously monitored by a laserinterferometer. The fracture kinetics was estimated by the iterationso that the S0-waveform computed to the assumed fracture kineticsbest represents the S0-waveform detected. Hydrogen inducedblistering was found to be caused by the succession of fast Mode-Ifracture with source rise times from 0.6 to 1.0 μs. The crackvolume estimated by the source simulation corresponded to that offine blistering with an opening displacement of 5μm. As theestimated fracture kinetics of hydrogen blistering coincide withthose of delayed fracture of high tension low alloy steel undertensile loading, the kinetics of first and micro-fractures andblistering induced by hydrogen gas precipitation appears to beindependent on the hydrogen solubility and strength of steels, theapplied stresses and the orientation of cracks.