Non-destructive testing on creep degraded 12% Cr-Mo-W-V ferritic test samples using Barkhausen noise

Abstract

Micro-magnetic non-destructive testing helps in evaluating the mechanical and structural integrity of ferromagnetic components (mostly steel) via local magnetic characterization. As a means of revealing the magnetic domain wall movements, the Barkhausen noise measurement method is a micro-magnetic non-destructive testing method of considerable potential and interest. The Magnetic Barkhausen Noise Energy (MBNenergy) method can be used to reconstruct local hysteresis cycles from Barkhausen noise measurements. These cycles constitute good indicators for understanding the magnetization process and the influence of microstructural and mechanical properties. In this article, the MBNenergy method is employed for evaluating the microstructural changes induced by creep/ageing of high chromium steel subjected to different creep test conditions as stress and temperature. The corresponding magnetic parameters are investigated in relation to precipitations and dislocations. After the experimental analysis, simulations are performed based on the Jiles-Atherton theory for the quasi-static magnetic behavior. This simulation approach yields physically meaningful model parameters that can be analyzed and linked to the sample microstructural characteristics, thereby enabling physical interpretation.