Which class of materials can be reliably inspected with magnetic particle testing?
Asnt Ndt Iii Mt Magnetization Principles
Question · Easy
On a B-H curve for a ferromagnetic steel, what does the point labeled Br represent?
Question · Medium
Chapter 1: Magnetization Principles and Physics
1.1 Magnetic Fields, Poles, and Domain Theory
Study guide
What does the coercive force Hc on a hysteresis loop quantify?
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The residual method of magnetic particle testing is generally appropriate for which class of materials?
What is the principal advantage of the continuous method over the residual method?
A circular magnetic field passing direct current axially through a solid cylindrical bar is best suited to detect discontinuities oriented how?
1.2 The Hysteresis Loop and B-H Curve
Longitudinal magnetization established by a coil running along a shaft is most sensitive to which crack orientation?
Why does ASME Section V Article 7 require that each area of a part be examined at least twice with the flux directions roughly perpendicular?
Curie temperature is the point at which a ferromagnetic material:
Question · Hard
What does the term magnetic permeability describe?
1.3 Longitudinal vs. Circular Magnetization Fields
Flux leakage at a tight surface crack is best described by which physical idea?
Which factor most strongly increases the chance of detecting a near-surface discontinuity by MT?
The skin effect on a ferromagnetic bar carrying alternating current means that:
What does Hall-effect probe measurement of tangential field strength on a part surface help confirm?
1.4 Magnetic Flux Leakage Theory and Defect Detectability
Why are MT signals weaker on a tight, subsurface discontinuity than on an identical-size open surface crack?
A part has been over-magnetized so much that flux density is well into saturation. What is the most likely effect on MT indications?
Per ASTM E709, what is the minimum lifting power of a portable AC yoke when measured at the maximum pole spacing?
Asnt Ndt Iii Mt Magnetization Techniques
What is the minimum required lifting power for a DC (electromagnetic) yoke at maximum pole spacing per ASME Section V Article 7?
1.5 Probability of Detection, Reliability, and Technique Validation
Using prods on a 1/2-inch-thick steel plate with 6 inches between prods, what continuous current is generally appropriate per ASTM E709?
What is the typical recommended prod spacing range for prod-method MT?
The prod technique is most commonly avoided on which class of finished product?
A solid round bar with a 2-inch outer diameter is to be circularly magnetized by passing direct current through the bar. What amperage range does ASTM E709 typically recommend?
Chapter 2: Direct Contact and Longitudinal Magnetization Techniques
2.1 Head Shots and Direct Contact Techniques
A hollow cylinder is to be inspected for inner-surface longitudinal cracks. Which technique is generally preferred?
Per ASTM E709, when an offset central conductor is used to inspect a large cylinder, the maximum circumferential length of part inspected on each shot is typically:
For coil-shot magnetization of a part with L/D ≥ 4 (length-to-diameter ratio of 4 or greater), the simplified low-fill coil formula commonly cited is:
When a part's length-to-diameter (L/D) ratio is less than 2, what is normally done before applying a coil-shot formula?
2.2 Prod Techniques and Localized Circular Magnetization
A head shot on a stationary horizontal MT bench means:
What is the main risk when using head-shot magnetization on a finished aerospace part?
Which technique establishes a circular field without passing current through the part itself?
A Level III is reviewing a multidirectional magnetization technique on a large casting. What is the technique's principal advantage?
2.3 Longitudinal Coil Magnetization and Calculations
Why are quick-break circuits typical on stationary half-wave DC MT benches?
A field indicator (pie gauge) with a cracked-and-brazed face is used to verify what?
Dry magnetic particles are best applied:
Asnt Ndt Iii Mt Magnetic Particles
Visible (color-contrast) MT particles work best when used with:
Chapter 3: Central Conductor, Yoke, and Vector Magnetization
3.1 Central Conductor (Induced Current) Techniques
The principal reason fluorescent MT is preferred over visible MT for high-sensitivity aerospace inspection is:
Per ASTM E1444, the typical settled concentration range for fluorescent wet magnetic particles in a centrifuge tube test is:
The typical settled concentration range for visible wet magnetic particles in a 100 mL centrifuge test is:
Particle size matters in MT because:
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