Non-Destructive Testing (NDT) Practice Test

If you suspect a crack after an eddy current inspection but are uncertain, which NDT method should be used for confirmation?

1. Magnetic Particle Testing

2. Ultrasonic Testing

3. Fluorescent Penetrant

4. X-ray Testing

The correct answer is: Fluorescent Penetrant

In cases where a crack is suspected after an eddy current inspection, using fluorescent penetrant testing is a highly effective method for confirmation. Fluorescent penetrant testing works by applying a liquid that seeps into surface cracks and flaws. After a specific dwell time, the excess penetrant is removed and a developer is applied, drawing out the penetrant from any flaws. Under ultraviolet light, these indications fluently reveal the location and extent of any surface-breaking defects, making it easier to confirm the presence of a crack. This method is particularly useful for detecting very fine cracks or surface defects that may not be easily visible to the naked eye, thus providing a clear indication of the state of the material under inspection. It complements findings from eddy current testing by giving a visual confirmation of any potentially problematic areas. Other options, while useful in various contexts, may not be as effective for directly confirming surface cracks detected via eddy current methods. Magnetic particle testing is limited to ferromagnetic materials, ultrasonic testing requires a good coupling medium and is more suited for subsurface defects, and X-ray testing is typically more complex and used for volumetric flaws rather than surface indications. Thus, fluorescent penetrant testing is the most appropriate choice for the scenario presented.