Magnetic Particle Inspection A practical guide

During the years since this book was first published in 1993 there have very few developments in the technology of magnetic particle inspection apart from improvements in instrumentation which has made the measurement of peak values of time varying currents practicable. The major changes have arisen from health and safety and environmental concerns. These involve chemicals and exposure of personnel to air-borne electromagnetic fields and long wave ultraviolet (UY.A). The changes in the acceptability of certain volatile halogenated hydrocar­ bons which led to the banning of 1, 1, 1 thichloroethane in 1995 were evident in 1993. The present discussions concerning the emissions of volatile organic compounds (VOCs) in general was also current and has now reached a stage where the effects of these deliberations will become evident over the next few years. Concerns over the exposure of personnel to airborne electromagnetic fields has been current for some years as has discussions to the effects of long wave ultraviolet (UY.A) on human skin. Recommendations as to maximum permit­ ted exposures over periods of time to both of these phenomena have been put forward and will doubtless form the basis of future legislation on the matter. A number of new specifications have appeared notably EN (European) and ISO specifications and some of these are still in preparation. Generally their impact will be minimal since these specifications are largely derived from existing documentation.

Preface. The history and basis of the magnetic particle testing method. Origins of defects in ferromagnetic materials. Essential magnetic characteristics for magnetic particle inspection. Methods of magnetizing components and materials for magnetic particle inspection. Sources of magnetic fields for magnetic particle inspection. Magnetic particles, their characteristics and application. Demagnetization. Procedures, specifications and documentation. Choosing a magnetic particle inspection method. Equipment for magnetic particle inspection. Quality control. Magnetism and magnetic properties of materials. Basic electromagnetic field theory. Analysis and measurement of magnetic fields. Health and safety in magnetic particle inspection. Environmental impact of magnetic particle inspection.