Why is the correct magnetic field strength important during testing?

The importance of the correct magnetic field strength during magnetic particle testing lies in its primary function to attract a sufficient quantity of magnetic particles to the surface being inspected. An appropriately calibrated magnetic field is essential for revealing surface and near-surface discontinuities, such as cracks or voids, that could compromise the integrity of the material being tested.

When the magnetic field strength is too weak, it may not adequately attract the particles, leading to insufficient indication of defects. Conversely, if the magnetic field is too strong, it could result in excessive noise and non-relevant indications, complicating the interpretation of the results. Therefore, achieving the right magnetic field strength is crucial to ensure the effectiveness and reliability of the testing process, enabling accurate defect identification while avoiding false indications.

In summary, the correct magnetic field strength plays a vital role in effectively attracting the magnetic particles where needed, directly influencing the success of the testing procedure and the quality of inspection results.