In magnetic particle testing, what is the goal of demagnetization?

In magnetic particle testing (MT), demagnetization is an essential step aimed primarily at preventing false readings that can arise from residual magnetism. When a component has been magnetized, it may retain some magnetic properties even after the inspection process. This residual magnetism can attract magnetic particles that are not indicative of actual defects in the material, potentially leading to misleading results.

By effectively demagnetizing the inspected object, technicians ensure that only the magnetic particles that are attracted to actual defects are visible. This accuracy allows for a better assessment of a component's integrity, facilitating the identification of true discontinuities and preventing unnecessary repairs or misinterpretations of the inspection results.

While enhancing visibility of defects, improving inspection speed, and increasing particle adherence are valuable aspects of the magnetic particle inspection process, they do not specifically address the issue of residual magnetism and its impact on the reliability of defect identification, making them less pertinent to the primary goal of demagnetization.