Magnetic Methods of Nondestructive Evaluation

Abstract

The sections in this article are Magnetic Methods For Cracks, Corrosion Pits, or Inclusions MAgnetic Methods For Microstructural Features Magnetic NDE Of Residual Stress Promising New Magnetic Techniques

A Study of Stress – Induced Subtle Magnetic Changes in a Mild Steel using Barkhausen Emission-Aided Analysis Approaches

“…Today, despite extensive and intensive theoretical and experimental investigations, [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], the applied stressinduced micromagnetic effects in ferromagnetic steels are complex and not yet fully understood. In general, the investigation of stress effects on polycrystalline ferromagnetic materials needs a basic reduction to a formulated set of problems solvable by detailed experimental investigations and/or mathematical analysis concerning the dynamics of domain wall motion.…”

“…In general, the investigation of stress effects on polycrystalline ferromagnetic materials needs a basic reduction to a formulated set of problems solvable by detailed experimental investigations and/or mathematical analysis concerning the dynamics of domain wall motion. As such, the application of stress to material results in a modification of strain state and a corresponding change of its elastic energy, [1], [2], [3], [4], [5], [6], [7], [8], [11], [12], [13], [14], [15] as well as in variations of effective strength levels of domain wall pinning sites, [3], [19]. This is related to the general fact that in ferromagnetic materials, the modification of internal stressstrain results in a change in the free energy and consequent changes in the micromagnetic response of the material, [8], [12], [28].…”

Extraction of Flux Leakage and Eddy Current Signals Induced by Submillimeter Backside Slits on Carbon Steel Plate Using a Low-Field AMR Differential Magnetic Probe

“…The flux leakage measurement refers to the study of magnetic flux that simply 'leaks' out of the sample in the vicinity of cracks, whereas the eddy current measurement is the study of eddy currents that are induced when a conductive sample is exposed to an external magnetic field. Some of the techniques that utilize the principle of flux leakage measurement are Magnetic Particle Inspection (MPI) [18], [19] and Magnetic Flux Leakage (MFL) [16], [20]. MFL has been shown to be able to detect deep defects in thick ferromagnetic plates.…”

Microscopic impact of creep damage incipience and development on the magnetic properties of ferromagnetic Cr–Mo steel

“…Since creep damage leads to the modification of defect structure, techniques that measure the local magnetic properties of steel should be useful for the detection of creep damage [2,3]. The Barkhausen effect (BE) [4,5] is very convenient as an NDE technique; however, not in the case of creep damage stage assessment because its intensity does not vary monotonically with creep damage (it at first increases and then decreases) [5,7].…”