What are the criteria for evaluating indications in Magnetic Particle Testing?

The criteria for evaluating indications in Magnetic Particle Testing focus primarily on size, shape, and response to magnetic fields. In this method, indications arise when magnetic particles accumulate at the discontinuities or flaws in a material, such as cracks or voids.

The size of an indication can provide insight into the significance of the flaw; larger indications may suggest more serious defects requiring further investigation. The shape of the indication can help to identify the type of discontinuity, such as long, linear indications suggesting cracks versus rounded shapes that may indicate voids. Additionally, the response to magnetic fields is crucial because the indications must be contrasted against the applied magnetic field to effectively reveal the relevance and severity of the detected flaws.

Other criteria, such as color and texture, while they may be relevant to certain conditions or types of tests, do not form the core basis for determining the significance of indications. Similarly, aspects like surface finish and alignment, or the material type and service history can influence the inspection process but are secondary to directly assessing the characteristics of the indication itself during Magnetic Particle Testing. Understanding these criteria allows inspectors to accurately evaluate and interpret the findings of the test, ensuring reliability in the assessment of structural integrity.