ASNT NDT II

Which discontinuity is most likely to produce a clear relevant indication during magnetic particle testing?

• AA surface-breaking crack in ferromagnetic steel that lies roughly perpendicular to the ma…
• BA deep internal void in aluminum
• CA smooth thickness change in nonmagnetic stainless steel
• DA lamination in brass far below the surface

Why is magnetic particle testing generally not used on aluminum parts?

• AAluminum has too much electrical resistance for inspection current
• BAluminum is not ferromagnetic and cannot hold the required magnetic flux for MT
• CAluminum surfaces are always too rough for particle mobility
• DAluminum cannot be cleaned well enough for nondestructive testing

When current is passed directly through a round bar between head stocks, what field is primarily produced and which discontinuities are best detected?

• AA longitudinal field that best reveals circumferential cracks
• BAn alternating field that best reveals surface porosity only
• CA circular field that best reveals longitudinal discontinuities
• DA residual field that best reveals transverse cracks

A shaft is magnetized with a coil shot. Which field and discontinuity orientation are most associated with that setup?

• AA longitudinal field that best reveals longitudinal seams
• BA circular field that best reveals circumferential cracks
• CNo useful field unless dry powder is used
• DA longitudinal field that best reveals circumferential cracks

Why are two magnetization directions commonly required in magnetic particle testing?

• ABecause a single field direction may miss discontinuities that run nearly parallel to tha…
• BBecause two directions are needed to make visible particles fluorescent
• CBecause the first shot only cleans the surface and the second does the inspection
• DBecause residual magnetism cannot form after only one shot

Wet fluorescent magnetic particles are often preferred for very fine fatigue cracking because they:

• AAre intended only for residual method inspections
• BMove more freely and usually provide higher sensitivity under UV-A
• CEliminate the need to control magnetic field direction
• DWork equally well on nonferromagnetic alloys

Which situation most strongly favors dry visible powder instead of wet fluorescent particles?

• AA polished bearing race inspected in a dark booth for fine grinding cracks
• BA smooth aerospace part where maximum sensitivity is the top priority
• CA rough weldment inspected outdoors where wet media is impractical
• DA nonferromagnetic casting with internal shrinkage

An indication repeatedly forms at a sharp change in section, and follow-up checks show no cracking. How is that indication most likely classified?

• AA relevant crack indication
• BA subsurface inclusion
• CA false indication caused only by lack of magnetization
• DA nonrelevant indication caused by geometry or section change

Residual magnetization method is least effective when the part material has which property?

• ALow retentivity and a tendency to lose most magnetism after current stops
• BHigh permeability and good particle mobility
• CA smooth machined surface
• DDiscontinuities open to the surface

What is a central conductor commonly used for in magnetic particle testing?

• AProducing longitudinal magnetization in a flat plate
• BProducing circular magnetization in a hollow part without sending current through the par…
• CMeasuring UV-A intensity at the inspection surface
• DDemagnetizing small hand tools after inspection

For a tight discontinuity slightly below the surface, which current type is generally more effective than AC?

• AAC because it concentrates only at the surface
• BVisible particles because they penetrate deeper than current
• CRectified DC because it generally provides deeper field penetration than AC
• DPermanent magnets because they eliminate orientation effects

Which observed particle pattern is most suggestive of a relevant crack indication?

• ARandom particles trapped in grease
• BBroad background buildup over the whole surface
• CSymmetrical buildup at both ends of a fillet radius
• DA sharp, well-defined linear accumulation of particles

A field indicator such as a pie gauge or QQI is primarily used to:

• AShow whether field direction and approximate surface field strength are adequate
• BReplace a gauss meter for precise residual field measurement
• CDetermine bath particle size distribution
• DIdentify the metallurgy of the part

Why is demagnetization often required after magnetic particle inspection?

• AIt makes fluorescent particles brighter during inspection
• BResidual magnetism can attract chips or interfere with later processing and service
• CIt converts all nonrelevant indications into false indications
• DVisible particles work only on demagnetized parts

Which demagnetization approach is commonly effective for many parts?

• AHold the part in a steady DC field for an extended time
• BRemagnetize once at a higher current in the same direction
• CApply an alternating field and gradually reduce it toward zero
• DQuench the part immediately after the final shot

What is the primary risk if prod tips make poor contact during prod magnetization?

• AConversion of a circular field into a longitudinal field
• BAutomatic demagnetization of the part
• CInability to create any field at all between the prods
• DArc burns and local surface damage at the contact points

When using visible magnetic particles on a dark part, what common step improves contrast and interpretation?

• AApply a thin white contrast coating
• BUse a stronger coil shot only
• CSkip surface cleaning before application
• DSwitch immediately to residual method

Why must a wet magnetic particle bath be adequately agitated before and during use?

• ATo increase the part temperature before magnetization
• BTo keep particles uniformly suspended so sensitivity remains consistent
• CTo convert fluorescent particles into visible particles
• DTo avoid the need for bath concentration checks

If particle concentration in a wet bath is too high, what is a likely result?

• AGreater field penetration into the part
• BAutomatic improvement in flaw discrimination
• CExcessive background that can mask fine indications
• DElimination of nonrelevant indications from geometry

What is the main advantage of multidirectional magnetization equipment?

• AIt works only with residual magnetization
• BIt removes the need for demagnetization after inspection
• CIt is limited to noncylindrical parts with flat surfaces
• DIt can reveal differently oriented discontinuities during one particle application

Why do magnetic particles collect at a crack during inspection?

• AFlux leakage creates local magnetic poles that attract the particles
• BGravity pulls particles into any surface depression
• CThe crack becomes electrically conductive during inspection
• DThe yoke legs physically push particles into the opening

To maximize the chance of detecting a suspected crack with a yoke, the magnetic field between the poles should be:

• AParallel to the crack as closely as possible
• BAs nearly perpendicular to the crack as practical
• CConfined only beneath one pole leg
• DWeaker than the earth's magnetic field

A hardened steel part strongly retains magnetism after inspection and is difficult to demagnetize. Which magnetic property best explains that behavior?

• ALow permeability only
• BLow electrical resistance
• CHigh retentivity and coercivity
• DHigh thermal conductivity

Which statement correctly distinguishes a false indication from a nonrelevant indication in magnetic particle testing?

• AA false indication is always a crack, while a nonrelevant indication is always porosity
• BFalse indications appear only with fluorescent particles, while nonrelevant ones appear o…
• CNonrelevant indications can occur only after demagnetization
• DA false indication comes from the inspection process itself, while a nonrelevant indicati…

After demagnetizing a part, which tool is most appropriate for checking whether residual magnetism is low enough for release or further processing?

• AA gauss meter or other instrument intended for residual field checks
• BA central conductor
• CA settling tube
• DA prod set

Liquid penetrant testing can reveal which type of discontinuity?

• AA void completely enclosed deep inside the material
• BA crack that is open to the surface
• CAn inclusion with no surface opening
• DA grain structure change below the surface

Why must paint, oil, and heavy oxide be removed before penetrant inspection?

• AThey make developer dry too quickly
• BThey increase bleedout so much that crack size is overstated
• CThey can block penetrant from entering surface openings
• DThey magnetize the surface and attract contaminants

During removal of excess water-washable penetrant, what is a common Level II concern?

• AAny rinsing improves sensitivity because surface dye is removed
• BWarmer rinse water always produces sharper indications
• CDeveloper fully restores any penetrant lost during rinsing
• DOver-washing can remove penetrant from discontinuities and weaken indications

What is the main purpose of developer in penetrant testing?

• ATo draw penetrant back out of discontinuities and improve indication visibility
• BTo chemically etch the part surface for better contrast
• CTo neutralize all residual cleaner on the part
• DTo make any surface stain disappear before evaluation

In penetrant interpretation, a linear indication is generally treated more seriously than a rounded indication because it is:

• AAlways deeper than a rounded indication
• BMore often associated with crack-like discontinuities
• CProduced only by fluorescent systems
• DImpossible to create by poor cleaning

Why is an emulsifier used in a post-emulsifiable penetrant system?

• ATo replace the developer step entirely
• BTo magnetize the part before inspection
• CTo make the excess penetrant water-removable after controlled contact time
• DTo seal discontinuities so they do not bleed out too early

Why can grit blasting alone be a poor final preparation method before penetrant inspection of crack-like discontinuities?

• AIt makes the surface too clean for penetrant to wet it
• BIt permanently changes the penetrant color response
• CIt removes the need for developer on machined surfaces
• DIt can smear metal over flaw openings and reduce penetrant entry

If penetrant dwell time is too short, what is the most likely effect?

• ATight discontinuities may not fill sufficiently, reducing sensitivity
• BIndications become brighter because less background remains
• CDevelopers will always correct the problem later
• DSurface roughness becomes irrelevant

In a post-emulsifiable penetrant process, excessive emulsifier contact time most likely causes:

• ADeeper penetrant penetration into the flaw
• BLoss of penetrant from discontinuities and weak indications
• CImproved discrimination on rough cast surfaces
• DAutomatic formation of a more uniform developer film

A cluster of many small rounded penetrant indications on a casting is most commonly associated with:

• AOne long fatigue crack
• BInsufficient UV-A intensity only
• CPorosity or multiple pinhole-type openings
• DMagnetic permeability changes

Fluorescent penetrant inspection requires what viewing condition for reliable evaluation?

• ABright sunlight to activate the dye
• BA heated booth above the penetrant flash point
• CTotal darkness with no UV-A source
• DAdequate UV-A intensity with controlled low ambient white light