Magnetic Particle Testing Methods Flashcards
7 cards from real NDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Magnetic Particle Testing Methods flashcards as text
Which magnetization technique is most effective for detecting longitudinal discontinuities in a cylindrical bar?
Answer: Circular magnetization using a central conductor
Circular magnetization creates a magnetic field circumferentially around the part, which is perpendicular to longitudinal discontinuities and maximizes their detection.
What is the purpose of the 'residual method' in magnetic particle testing?
Answer: Applying particles after the magnetizing current is turned off
The residual method applies particles to a part after magnetization is complete, relying on the retained residual magnetic field to hold particles at discontinuity locations.
When using the continuous method of magnetic particle testing, particles are applied:
Answer: While the magnetizing current is flowing
In the continuous method, magnetic particles are applied while the magnetizing current is actively flowing, taking advantage of the stronger applied field rather than only residual magnetism.
A head shot (contact shot) in magnetic particle testing produces which type of magnetization?
Answer: Circular
Passing current directly through the part between head contacts creates circular (circumferential) magnetization around the part's cross-section.
What is the primary advantage of multidirectional magnetization in magnetic particle testing?
Answer: Detection of discontinuities in multiple orientations in one operation
Multidirectional magnetization sequences through different field directions rapidly, allowing detection of variously oriented discontinuities without repositioning the part.
When using prod magnetization, what is the recommended current range per inch of prod spacing according to ASTM E1444?
Answer: 100–125 amperes per inch
ASTM E1444 specifies 100–125 amperes per inch of prod spacing as the standard current range for prod magnetization of most materials.
Which of the following best describes 'swinging field' magnetization?
Answer: Rapidly switching between two or more directional fields to detect all orientations
Swinging field (multidirectional) magnetization rapidly cycles the field through multiple directions so that all discontinuity orientations are detectable in a single inspection step.