Magnetic Barkhausen noise analysis of residual stress and carburization

Magnetic Barkhausen noise analysis is an effective non-destructive testing technique for determining both residual stress and carburization, with potential for improving the accuracy of remaining-life estimates of critical components in operational plant such as that used in thermal power stations and the petrochemical industry. We have measured Barkhausen noise in magnetic Durehete 1055 samples under stress and in carburized ethylene pyrolysis tubes. The Barkhausen power as a function of applied field is modeled using Sablik's function for Barkhausen power as a function of irreversible differential permeability (mu (irr)); the Jiles-Atherton model of hysteresis is used to determine gi as a function of applied field.