Which of the following is a characteristic of Grade A magnetic particles?

Grade A magnetic particles are characterized as ultra-fine particles specifically designed for sensitive inspections. This fine size allows them to conform easily to small discontinuities and surface irregularities, which is essential in detecting minor flaws in materials. The increased sensitivity of ultra-fine particles enhances the ability to identify smaller defects that might otherwise go unnoticed with larger particles.

The choice of magnetic particle size is critical in ensuring effective inspection results; while medium-sized and coarse particles are suitable for larger defects, ultra-fine particles are specifically tailored for applications where precision and sensitivity are paramount. The usage of Grade A particles typically aligns with more stringent testing requirements, particularly in critical applications where safety and reliability are essential.