McqMate
Chapters
201. |
Magnetic particles testing is most likely to find subsurface discontinuities in: |
A. | Soft steels with high permeability |
B. | Soft steels with low permeability |
C. | Hardened steels with low permeability |
D. | Hardened steels with high permeability |
Answer» A. Soft steels with high permeability |
202. |
Which of the following is not an advantage of magnetic particles testing? |
A. | Fast and simple to perform |
B. | Can detect discontinuities filled with foreign material |
C. | Most reliable for finding surface cracks in all types of material |
D. | Works well through a thin coat of paint |
Answer» C. Most reliable for finding surface cracks in all types of material |
203. |
Which of the following does not represent a limitation of magnetic particle testing? |
A. | The type of materials which may be effectively tested |
B. | The directionality of the magnetic field |
C. | The need for demagnetization |
D. | The ability to detect discontinuities filled with foreign material |
Answer» D. The ability to detect discontinuities filled with foreign material |
204. |
The most effective NDT method for locating surface cracks in ferromagnetic materials is: |
A. | Ultrasonic testing |
B. | Radiographic testing |
C. | Magnetic particle testing |
D. | Liquid penetrant testing |
Answer» C. Magnetic particle testing |
205. |
Which of the following may cause magnetic particle test indications? |
A. | A joint between two ferromagnetic materials of different permeability |
B. | A shrink fit joint in ferromagnetic materials |
C. | A brazed joint in ferromagnetic materials |
D. | All of the above |
Answer» D. All of the above |
206. |
A discontinuity which is produced during solidification of the molten metal is called: |
A. | Inherent |
B. | Processing |
C. | Service |
D. | None of the above |
Answer» A. Inherent |
207. |
Pipe would be classified as what type of discontinuity? |
A. | Inherent |
B. | Processing |
C. | Service |
D. | None of the above |
Answer» A. Inherent |
208. |
A seam would be classified as what type of discontinuity? |
A. | Inherent |
B. | Processing |
C. | Service |
D. | None of the above |
Answer» B. Processing |
209. |
A lamination in steel plate would be classified as what type of discontinuity? |
A. | Inherent |
B. | Processing |
C. | Service |
D. | None of the above |
Answer» B. Processing |
210. |
An internal rupture caused by working steel at improper temperatures is called a: |
A. | Lap |
B. | Cold shut |
C. | Forging burst |
D. | Slag inclusion |
Answer» C. Forging burst |
211. |
Cracks which are caused by alternating stresses above a critical level are called: |
A. | Stress corrosion cracks |
B. | Cycling cracks |
C. | Critical cracks |
D. | Fatigue cracks |
Answer» D. Fatigue cracks |
212. |
Cracks which are caused by a combination of tensile stress and corrosion are called: |
A. | Stress corrosion cracks |
B. | Cycling cracks |
C. | Critical cracks |
D. | Fatigue cracks |
Answer» A. Stress corrosion cracks |
213. |
Which of the following are ferromagnetic materials? |
A. | Aluminium, iron, copper |
B. | Iron, copper, nickel |
C. | Copper, aluminium, silver |
D. | Iron, cobalt, nickel |
Answer» D. Iron, cobalt, nickel |
214. |
The reverse magnetising force necessary to remove a residual magnetic field from a test piece after it has been magnetically saturated is called: |
A. | Hysteresis |
B. | Coercive force |
C. | Demagnetising flux |
D. | Reverse saturation |
Answer» B. Coercive force |
215. |
Magnetic lines of force enter and leave a magnet at: |
A. | Saturation |
B. | L/D ratios of greater than 4 to 1 |
C. | Flux concentration points |
D. | Poles |
Answer» D. Poles |
216. |
The ease with which a magnetic field can be established in a test piece is called: |
A. | Reluctance |
B. | Retentivity |
C. | Permeability |
D. | Electromagnetism |
Answer» C. Permeability |
217. |
Opposition to establishment of a magnetic field is called: |
A. | Reluctance |
B. | Retentivity |
C. | Permeability |
D. | Electromagnetism |
Answer» A. Reluctance |
218. |
The ability of a material to remain magnetic after the magnetising force is removed is called: |
A. | Reluctance |
B. | Retentivity |
C. | Permeability |
D. | Electromagnetism |
Answer» B. Retentivity |
219. |
A magnetic field which is contained completely within the test piece is called a: |
A. | Confined field |
B. | Longitudinal field |
C. | Circular field |
D. | Saturated field |
Answer» C. Circular field |
220. |
Which of the following produces a circular field? |
A. | Coil |
B. | Head shot |
C. | Yoke |
D. | All of the above |
Answer» B. Head shot |
221. |
A technique used to find transverse discontinuities at the ends of longitudinally magnetised bars by the use of transient currents is called: |
A. | A coil technique |
B. | A fast break technique |
C. | A yoke technique |
D. | A head shot |
Answer» B. A fast break technique |
222. |
A leakage field is strongest when a discontinuity interrupts the magnetic flux lines at an angle of: |
A. | Zero degrees |
B. | 45 degrees |
C. | 90 degrees |
D. | 180 degrees |
Answer» C. 90 degrees |
223. |
The best method of inducing a circular field in a tube is by a: |
A. | Central conductor |
B. | Head shot |
C. | Coil |
D. | Prod technique |
Answer» A. Central conductor |
224. |
Magnetic flux density is zero at: |
A. | The inside surface of a tube magnetised with a central conductor |
B. | The outside surface of a tube magnetised with a central conductor |
C. | The outside surface of a bar magnetised with a head shot |
D. | The centre of a bar magnetised with a head shot |
Answer» D. The centre of a bar magnetised with a head shot |
225. |
Magnetic flux density is highest at: |
A. | The outside surface of a non-ferromagnetic tube magnetised with a central conductor |
B. | The inside surface of a non-ferromagnetic tube magnetised with a central conductor |
C. | The outside surface of a ferromagnetic tube magnetised with a central conductor |
D. | The inside surface of a ferromagnetic tube magnetised with a central conductor |
Answer» D. The inside surface of a ferromagnetic tube magnetised with a central conductor |
226. |
An important consideration when using a direct contact method is: |
A. | Lifting power of the yoke |
B. | Coil diameter |
C. | Preventing arc burns |
D. | Field strength adjacent to the coil inside diameter |
Answer» C. Preventing arc burns |
227. |
A prod method would be most sensitive to cracks: |
A. | Parallel to a line connecting the prod contact points |
B. | Tangential to a radius from each prod contact point |
C. | Perpendicular to a line connecting the prod contact points |
D. | Perpendicular to the long axis of the coil |
Answer» A. Parallel to a line connecting the prod contact points |
228. |
When using prods, arc burns may be caused by which of the following? |
A. | Dirty contact tips |
B. | Inadequate pressure |
C. | Too large a magnetic current |
D. | All of the above |
Answer» D. All of the above |
229. |
The important difference between AC and DC current for magnetic particle testing purposes is: |
A. | The skin effect caused by DC adds mobility to the magnetic particles |
B. | The resulting AC magnetic fields are more difficult to demagnetize |
C. | The DC magnetic fields are more penetrating |
D. | The AC magnetic fields are stronger |
Answer» C. The DC magnetic fields are more penetrating |
230. |
The ‘skin’ effect would be most noticeable in which of the following? |
A. | A magnetic conductor carrying a DC current |
B. | A nonmagnetic conductor carrying a DC current |
C. | A magnetic conductor carrying a 50 Hz AC current |
D. | A nonmagnetic conductor carrying a 50 Hz AC current |
Answer» D. A nonmagnetic conductor carrying a 50 Hz AC current |
231. |
The most common source of DC current for magnetic particle testing is: |
A. | Motor generators |
B. | Rectified AC |
C. | Storage batteries |
D. | None of the above |
Answer» B. Rectified AC |
232. |
Fields generated in ferromagnetic material with AC current are useful for locating: |
A. | All discontinuities |
B. | Surface cracks |
C. | Subsurface discontinuities |
D. | Internal porosity |
Answer» B. Surface cracks |
233. |
A common rule of thumb to use for current required in circular magnetisation: |
A. | 1000 amps/25mm of diameter |
B. | 1000 ampere turns/25mm of diameter |
C. | 1000 amps/25mm of prod spacing |
D. | None of the above |
Answer» B. 1000 ampere turns/25mm of diameter |
234. |
The formula, NI = 45000/(L/D), is used to calculate the proper magnetising current for: |
A. | Prod magnetization |
B. | A head shot |
C. | A central conductor |
D. | Coil magnetisation |
Answer» D. Coil magnetisation |
235. |
The formula, NI = 45000/(L/D), gives proper magnetising current for a coil, regardless of coil size as long as: |
A. | The test piece is not larger than 1/10 the cross sectional area of the coil |
B. | AC current only is used |
C. | The test piece essentially fills the coil |
D. | The test piece is held tightly against the coil |
Answer» A. The test piece is not larger than 1/10 the cross sectional area of the coil |
236. |
For direct contact magnetising methods, the magnetic field is oriented in what direction relative to the current direction? |
A. | Parallel |
B. | At 45 degrees |
C. | At 90 degrees |
D. | At 180 degrees |
Answer» C. At 90 degrees |
237. |
For direct contact magnetising methods, current should be flowing in what direction relative to expected discontinuities? |
A. | Parallel |
B. | At 45 degrees |
C. | At 90 degrees |
D. | At 180 degrees |
Answer» A. Parallel |
238. |
What is the magnetic field strength at the surface of a 100 mm diameter bar as compared to that at the surface of a 50 mm diameter bar, each carrying 1000 amps of current? |
A. | Twice |
B. | One half |
C. | One quarter |
D. | Four times |
Answer» B. One half |
239. |
What is the magnetic field strength at the surface of a 25mm diameter bar as compared to that at the surface of a 50mm diameter bar, each carrying 1000 amps of current? |
A. | Twice |
B. | One half |
C. | One quarter |
D. | Four times |
Answer» A. Twice |
240. |
The magnetic field outside a conductor decreases: |
A. | Exponentially |
B. | In a linear manner |
C. | Inversely with distance |
D. | Inversely with the square of distance |
Answer» B. In a linear manner |
241. |
How is the magnetic field strength at the surface of a magnetic conductor having permeability, µ, related to the magnetic field strength, F, at the surface of a nonmagnetic conductor carrying the same current? |
A. | F × µ |
B. | Same |
C. | F/µ |
D. | Not related |
Answer» B. Same |
242. |
Compared to the magnetic field strength at the outer surface, the magnetic field strength, at the centre of a hollow, nonmagnetic conductor carrying DC current is: |
A. | I/D |
B. | The same |
C. | Zero |
D. | Need more information to determine |
Answer» C. Zero |
243. |
How is the magnetic field strength, F, just outside a magnetic conductor having permeability, µ, related to that just outside a nonmagnetic conductor of the same size, carrying the same current? |
A. | F × µ |
B. | Same |
C. | (F)/µ |
D. | Not related |
Answer» B. Same |
244. |
Which of the following describes the shape of particles used for dry magnetic particle testing? |
A. | Spherical |
B. | Angular |
C. | Elongated |
D. | Mixture of elongated and globular |
Answer» D. Mixture of elongated and globular |
245. |
Which of the following particles would be most sensitive? |
A. | Wet |
B. | Dry |
C. | Depends on the test piece permeability |
D. | None of the above |
Answer» B. Dry |
246. |
Which of the following colours is readily available for magnetic particle test powder? |
A. | Red |
B. | Gray |
C. | Black |
D. | All of the above |
Answer» D. All of the above |
247. |
A magnetic particle testing technique in which the test piece is magnetised and magnetic particles applied after the magnetising force has been removed is called the: |
A. | Magnetic method |
B. | Continuous method |
C. | Residual method |
D. | Discontinuous method |
Answer» C. Residual method |
248. |
Which of the following characteristics would be most important in a test piece which is to be tested using the residual method? |
A. | High rententivity |
B. | High permeability |
C. | Low reluctance |
D. | Low permeability |
Answer» A. High rententivity |
249. |
The wet method is superior to dry particles for detecting: |
A. | Subsurface discontinuities |
B. | Fine surface cracks |
C. | Open surface cracks |
D. | None of the above |
Answer» B. Fine surface cracks |
250. |
Selection of magnetic particle colour is based on: |
A. | Optimum performance of magnetic particle/developer |
B. | Colour of inspection light available |
C. | Obtaining maximum contrast with the test piece background |
D. | Optimum colour response of the human eye |
Answer» C. Obtaining maximum contrast with the test piece background |
251. |
The residual method is applicable to: |
A. | Surface discontinuities only |
B. | Subsurface discontinuities only |
C. | Either surface or subsurface discontinuities |
D. | All but tight surface cracks |
Answer» A. Surface discontinuities only |
252. |
Highest sensitivity to fine surface cracks would be obtained by which of the following techniques? |
A. | Residual field, wet method |
B. | Residual field, dry method |
C. | Continuous field, wet method |
D. | Continuous field, dry method |
Answer» C. Continuous field, wet method |
253. |
A residual field is always less than a continuous field because? |
A. | The magnetic field, as shown by a hysteresis curve, is zero when there is no magnetising force |
B. | The magnetic field, as shown by a hysteresis curve, is less when there is no magnetising force |
C. | The magnetic field, as shown by a hysteresis curve, is greater when there is no magnetising force |
D. | None of the above |
Answer» B. The magnetic field, as shown by a hysteresis curve, is less when there is no magnetising force |
254. |
Where possible, circular magnetisation is preferable to longitudinal magnetization because: |
A. | Less current is required |
B. | Stronger fields are obtained |
C. | Fewer confusing secondary poles are produced |
D. | None of the above is true |
Answer» D. None of the above is true |
255. |
Which of the following is a disadvantage of the dry method? |
A. | Ease of application with portable equipment |
B. | Superior sensitivity for fine surface cracks |
C. | Good particle mobility with AC and HWDC |
D. | Good sensitivity for subsurface discontinuities |
Answer» B. Superior sensitivity for fine surface cracks |
256. |
Which of the following is an advantage of the dry method |
A. | Good sensitivity for subsurface discontinuities |
B. | Faster than wet method for quantities of small test pieces |
C. | Easily applied in an automated system |
D. | Easy coverage of surfaces of irregularly shaped test pieces |
Answer» A. Good sensitivity for subsurface discontinuities |
257. |
Loss of fine particle sizes due to re-use of dry particles would probably lead to: |
A. | Loss of sensitivity to larger discontinuities |
B. | Loss of sensitivity to finer discontinuities |
C. | Unpredictable results |
D. | Slower inspection speeds |
Answer» B. Loss of sensitivity to finer discontinuities |
258. |
Which of the following is a disadvantage of the wet method? |
A. | It is the most sensitive method for detection of very fine surface cracks |
B. | Rapid testing of large quantities of small test pieces |
C. | Readily adaptable to mechanised equipment |
D. | Excellent detection of completely subsurface discontinuities |
Answer» D. Excellent detection of completely subsurface discontinuities |
259. |
Which of the following is an advantage of the wet method? |
A. | Excellent detection of completely subsurface discontinuities |
B. | Ease of bath recovery and re-use |
C. | Low flash point ensures freedom from fire hazards |
D. | Relatively clean and easy to work with |
Answer» B. Ease of bath recovery and re-use |
260. |
The primary reason for using water rather than oil as a suspension medium for wet method baths is that: |
A. | Water is more chemically inert than oil |
B. | Bath flammability hazards are eliminated |
C. | Water has the capability to dissolve the needed rust inhibitors |
D. | Water baths may be used at lower temperatures than oil baths |
Answer» B. Bath flammability hazards are eliminated |
261. |
A disadvantage of fluorescent magnetic particles is: |
A. | Darkened area and black light are required |
B. | Abnormally high sensitivity |
C. | Only dry particles are available |
D. | Only wet concentrate is available |
Answer» A. Darkened area and black light are required |
262. |
A common physiological effect of black light inspection on the inspector is: |
A. | Burned retinas of the eyes |
B. | Rejected cornea syndrome |
C. | Eye fatigue |
D. | Retarded iris control |
Answer» C. Eye fatigue |
263. |
A common physiological effect of black light inspection on the inspector is: |
A. | Burned retinas of the eyes |
B. | Rejected cornea syndrome |
C. | Eyeball fluorescence |
D. | Retarded iris control |
Answer» C. Eyeball fluorescence |
264. |
Which of the following represents ultraviolet light of wavelengths which are potentially injurious (1 Å = 10-10m) |
A. | 2000 to 3200Å |
B. | 3200 to 4000 Å |
C. | 4000 to 4600Å |
D. | 4600 to 5200 Å |
Answer» A. 2000 to 3200Å |
265. |
Dyes which receive light at one wavelength and re-emit light of another wavelength are called: |
A. | L.E.Ds |
B. | Phosphorescent |
C. | Luminescent |
D. | Fluorescent |
Answer» D. Fluorescent |
266. |
Most fluorescent dyes used for magnetic particle testing fluoresce what colour? |
A. | Blue green |
B. | Yellow green |
C. | Blue black |
D. | Red orange |
Answer» B. Yellow green |
267. |
The best available source of black light for inspection is: |
A. | The mercury vapour lamp |
B. | The fluorescent tube |
C. | The incandescent bulb |
D. | Sunlight |
Answer» A. The mercury vapour lamp |
268. |
Which of the following would be likely to cause variations in the output of an inspection black light? |
A. | Voltage fluctuations |
B. | Aged bulb |
C. | Dirty filter |
D. | All of the above |
Answer» D. All of the above |
269. |
The temperature above which steels become nonmagnetic is called the: |
A. | Zero retentivity |
B. | Curie point |
C. | Demagnetisation temperature |
D. | Random polar point |
Answer» B. Curie point |
270. |
The temperature above which most soft steels become nonmagnetic is about: |
A. | 440ºC(770oF) |
B. | 523ºC (975ºF) |
C. | 626ºC (1160ºF) |
D. | 754ºC (1390ºF) |
Answer» D. 754ºC (1390ºF) |
271. |
The most common method of demagnetising small test pieces is: |
A. | Heat treatment |
B. | Shot peening |
C. | Passing through an AC coil |
D. | Direct contact with AC current |
Answer» C. Passing through an AC coil |
272. |
Demagnetisation with reversing DC is more effective than AC because: |
A. | DC is more penetrating |
B. | Demagnetisation is assisted by the skin effect |
C. | DC is more direct |
D. | Not true - AC is more effective |
Answer» A. DC is more penetrating |
273. |
The type of discontinuity which magnetic particle testing most effectively locates is: |
A. | Slag inclusions |
B. | Magnetic writing |
C. | Porosity |
D. | Surface cracks |
Answer» D. Surface cracks |
274. |
An indication which is formed when two pieces of magnetised steel come in contact with each other is called: |
A. | A metallurgical discontinuity |
B. | Magnetic writing |
C. | Magnetic transfer |
D. | A ferromagnetic notch |
Answer» B. Magnetic writing |
275. |
Magnetic particle test indications which are due to cold work can best be removed by: |
A. | Demagnetisation |
B. | Using a lower current |
C. | Re-crystallisation |
D. | Heat treating |
Answer» D. Heat treating |
276. |
Which of the following might cause non-relevant indications? |
A. | Over magnetisation |
B. | Indications at the edges of a braze joint |
C. | A joint between hard and soft steels |
D. | All of the above |
Answer» D. All of the above |
277. |
An inspection for surface and subsurface discontinuities in ferromagnetic welds would best be accomplished by which of the following techniques? |
A. | Prods |
B. | AC yoke |
C. | Half wave DC yoke |
D. | None of the above |
Answer» A. Prods |
278. |
A continuous linear indication along the centre of a fillet weld would most likely be a: |
A. | Crater crack |
B. | Overlap |
C. | Root indication |
D. | None of the above |
Answer» C. Root indication |
279. |
Wet magnetic particle bath strength is checked by which of the following? |
A. | Specific gravity |
B. | Optical density |
C. | Settling test |
D. | None of the above |
Answer» C. Settling test |
280. |
Which of the following describes the best technique for applying dry magnetic particles to a test piece? |
A. | Dip the test piece in a tank of dry particles while current is flowing |
B. | Apply with an electrostatic spray gun at approximately 30 PSIG |
C. | Gently pour the powder onto the test piece |
D. | Shake or dust the powder onto the test piece with minimum velocity |
Answer» D. Shake or dust the powder onto the test piece with minimum velocity |
281. |
An advantage of AC equipment over DC is: |
A. | AC is more penetrating |
B. | AC is less hazardous |
C. | AC makes the magnetic particles more mobile on the test surface |
D. | AC equipment is heavier than DC |
Answer» C. AC makes the magnetic particles more mobile on the test surface |
282. |
When the orientation of likely discontinuities is unknown, what is the minimum number of magnetising operations required to perform an adequate test? |
A. | 1 |
B. | 2 |
C. | 3 |
D. | None of the above |
Answer» B. 2 |
283. |
Maximum practical prod spacing is about: |
A. | 100 mm |
B. | 200 mm |
C. | 300 mm |
D. | 450 mm |
Answer» B. 200 mm |
284. |
Magnetic lines of flux which are parallel to a discontinuity produce: |
A. | Strong indications |
B. | Weak indications |
C. | No indications |
D. | Fuzzy indications |
Answer» C. No indications |
285. |
The area of maximum induced field strength using a yoke is: |
A. | At the north pole of the yoke |
B. | At the south pole of the yoke |
C. | The area directly between the poles |
D. | On the outside of the pole pieces |
Answer» C. The area directly between the poles |
286. |
A minimum of external poles are produced by what type of magnetisation? |
A. | Continuous |
B. | Residual |
C. | Circular |
D. | Longitudinal |
Answer» C. Circular |
287. |
A split coil would most likely be used with a: |
A. | DC yoke |
B. | Split phase AC yoke |
C. | Stationary magnetic particle unit |
D. | Portable magnetic particle unit |
Answer» D. Portable magnetic particle unit |
288. |
The most common harmful effect of exposure to black light is: |
A. | Eyeball fluorescence |
B. | Burned retinas |
C. | Skin burns |
D. | None of the above |
Answer» A. Eyeball fluorescence |
289. |
Which of the following types of magnetic fields may be present without any external evidence? |
A. | Circular |
B. | Longitudinal |
C. | Secondary |
D. | Tertiary |
Answer» A. Circular |
290. |
The primary reason for using water rather than oil as a suspension medium for wet method baths is that |
A. | Water is more chemically inert than oil |
B. | Bath flammability hazards are eliminated |
C. | Water has the capability to dissolve the needed rust inhibitors |
D. | Water baths may be used at a lower temperature than oil baths |
Answer» B. Bath flammability hazards are eliminated |
291. |
Wet magnetic particle strength is checked by which of the following? |
A. | Specific gravity |
B. | Optical density |
C. | Settling test |
D. | None of the above |
Answer» C. Settling test |
292. |
A residual circular field may be objectionable because: |
A. | Grinding may produce heat cracks |
B. | Machining may create external poles |
C. | Heat treating may lead to tight surface cracks\ |
D. | All of the above |
Answer» B. Machining may create external poles |
293. |
A prod method would be most sensitive to cracks: |
A. | Parallel to a line connecting the prod contract points |
B. | Tangential to a radius from each prod contact point |
C. | Perpendicular to a line connecting the prod contact points |
D. | Perpendicular to the long axis |
Answer» A. Parallel to a line connecting the prod contract points |
294. |
Maximum practical prod spacing for a 2000 amp unit is about: |
A. | 100 mm |
B. | 200 mm |
C. | 300 mm |
D. | 450 mm |
Answer» B. 200 mm |
295. |
Demagnetisation with reversing DC is more effective than AC because: |
A. | DC is more penetrating |
B. | Demagnetisation is assisted by the skin effect |
C. | DC is more direct |
D. | Not true-AC is more effective |
Answer» A. DC is more penetrating |
296. |
Fluorescent magnetic particle indications should be inspected under |
A. | Fluorescent light |
B. | Any light |
C. | Black light |
D. | Red light |
Answer» C. Black light |
297. |
Cracks which are caused by a combination of tensile stress and corrosion are called: |
A. | Intergranular stress corrosion cracking |
B. | Cycling cracks |
C. | Stress corrosion cracking |
D. | Fatigue cracks |
Answer» C. Stress corrosion cracking |
298. |
The type of discontinuity potentially most harmful to the useful life of a part is: |
A. | Slag inclusions |
B. | Magnetic writing |
C. | Porosity |
D. | Surface cracks |
Answer» D. Surface cracks |
299. |
Magnetic particle test indications which are due to cold work can best be removed by: |
A. | Demagnetisation |
B. | Using a lower current |
C. | Using penetrant testing |
D. | Re-heat treating |
Answer» D. Re-heat treating |
300. |
Which of the following might cause non relevant indications? |
A. | Magnetic writing |
B. | Indications at the edges of a braze joint |
C. | A joint between hard and soft steels |
D. | All of the above |
Answer» D. All of the above |
Done Reading?