ASNT Level III MT Questions and Answers

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MT 1. Which of the following discontinuities could be classified a service induced discontinuity a. fatigue crack b. porosity C. machining tear d. lap 2. Which of the following discontinuities might be found in rolled plate a. lamination b. shrinkage C. lack of fusion d. undercut 3. A continuous linear indication can be caused by which of the following a. porosity b. slag inclusion C. pitting d. cracks 4. Which of the following discontinuities might be und in forged test part a. shrinkage b. bleed out C. laps d. undercut 5. The penetrant indication of a cold shut of casting will by a. dotted or smooth continuous line b. small spherical indications C. porosity aligned in a line d. cold shut is not shown in PT 6. Which of the owing is a discontinuity the might be found in rolled bar stock a. blow holes b. shrinkage laps C. cracks or seams d. insufficient penetration 7. The part is forging - description : indication is sharp, half moon shape-NOT deep and is called a. lap b. center line porosity C. cracks or seams d. insufficient penetration 8. The penetrant indication of a forging lap will normally be a. a round or nearly round indication b. a cluster of indications C. continuous line d. a dotted line 9. Part is a thick AI plate with a Vee weld. Description - the indication appears in an area that is somewhat dish shaped. The indication extends from the center in a spopke formation. The indication is a. shrinkage b. nonrelevant C. quench crack d. a crater crack 10. A heat treatment crack is most likely to show what type of indication a. a fine, blue white indication b. an intermittent fine line indication C. a bright yellow green indication d. a line of bright dots11. Which one of th following is not probably from a fatigue crack a. a fine line of dots b. a fine, straight line C. an area 0 fine sharp indications d. a fine, sh irp and jagged or forked indication 12. A defect can Iso be which of the following a. discontinu ty b. blemish C. flaw d. all of the above 13. Which of the llowing discontinuities would not be revealed in penetrant testing crater crack b. forging lap grinding cracks d. nometallic inclusions 14. Penetrant may not show which of the following a. inclusions b. bursts d. quench cracks 15. Which of the following welding methods would not equire the removal slag and oxides prior to the penetrant indication a. metal inert gas b. rod weld C. submergeu arc d. electroslag welds e. all of the above needs precleaning 1. Which one of the following is ferromagnetic a. a nickel alloy b. a copper alloy C. a low carbon steel both a & C 2. The magnetic lines of force contained in a permagnet magnet leave from the higher magnetic permeability to lower at a. at northe pole b. at south pole C. at both poles d. it cannot leave the magnet 3. In a current carrying conductor, the magnetic lines of force is always perpendicular to the direction of current and the field strength is maximum at a. at the center of the conductor b. at the surface of the C. only on the surface of a ferromagnetic conductor d. maximum at the inner surface of a nonmagnetic conductor 4. A permanent magnet always produce a. a circular field b. a longitudinal field C. a vector field d. direction on the direction of placement of the magnet on the job 5. Which of the steels mentioned below is difficult to magnetize: a. steel with low carbon content b. steel with very high permeability steel with very low permeability and generally less than 100 steel before to heat treatment6. AC meter shows 1000 amps. The actual current passed on the job is: b. 1.14 times the meter reading 1.41 times the meter reading d. 1.41 times less than that read on the meter is S: me as read on the meter 18. The recomme nded I rod spacing is: a. above inch b. below 3 inch c. betwee ! 3 and 8 inch d. below inch. 19. In order to detect defects in different directions in a material by magnetic particle inspection, it best to use: a. two or more fields in different directions b. only one field but with varying current density other probe locations d. with different frequencies 20. An example of a nonrelevant indication that would be classed as a magnetic irregularity rather than an actual discontinuity could be caused by: a. a slag packet b. grinding cracks an abrupt change in the hardness of part d. none of the above 21. Reluctance in the magnetic circuit can be compared to in n AC circuit f. inductance g. impedance h. resistance i. inductive reactance 22. A 90 inch long and 5 inch dia is to be tested using coil magnetization. For best results which one of the following would you recommend, j. 4 equal segments and using the formula NI=45000/(L/D) k. 5 equal segments and using the formula NI=45000/(L/D) with enough overlap and with more than 5 coil shots. 1. 3 equal shots and completely wrapping the coil m. cannot be tested. 23. If an overall pattern (sometimes circular lines) appears on the test surfaces, how should the inspector reprocess the test piece? a. retest at a higher amps. b. demagnetize and retest retest at lower amperage compare Que d both a and b 24 What happens to a magnetic material when it reaches to curie temperature? a. it becomes paramagnetic b. it becomes dia magnetic it becomes nonmagnetic compare with d. it becomes radioactive 10. 325. MT equipmer has got maximum capacity of 1500 mps. If it is desired to magnetize job with solenoid how many turns are required to test a bar of 15 inch long an 3 inch in dia. 5 b. 6 turns C. 71 d. 8 turns 26. Which one of them would produce a strong external poles a. shaft tested with head shot b. ! shaft tested with central conductor shaft tested with coild shot d. shaft tested with direct method of magnetization by passing current on the job in the direction of long axis 27. The most magnetic properties of powder for magnetic icle testing is a. low permeability and high retentivity b. high permeability and low retentivity c. high permeability d. low retentivity 28. The depth of of a magnetizing current on the test depends on the use of a. type of current b. strength of the current the permeability of the medium d. all of the above 29. A shaft tested with head shot produced two indication - one sharp and the other fuzzy. The location namely surface or subsurface can be confirmed by a. the fuzzy indication would not appear when tested with AC b. the strong indication would not appear when tested with AC the strong indication would be fuzzy when tested with AC d. all of the abc e statements are correct 30. A 45 inch long shat is to be tested for circumferential surface crack oriented perpendicular to the long axis of the shaft. The most suitable method of magnetization a. a head shot b. a coil shot with suitable ampere turns a central conductor d. any one of the above 31. The above job referred in qn30 is to be inspected for cracks oriented in any direction. In such case we need to magnetise the job a. more than on head shot to cover the entire length b. a coil shot with suitable ampere turns one head shot and with a minimum of 3 coil shots d. one coil shot using the formula NI = 45,000/L/D 32. Two iron shafts, one magnetized and another unmagnetised would exhibit a. all the magnetic domains randomly oriented for a magnetized job b. all the magnetic domains orderly oriented in a magnetized job C. all the magnetic domains orderly oriented in a magnetized job d. no presence of magnetic domains in iron shaft 433. high permeability material is to betested ith prod technique and the current requirement is 90-110 anps per inch of prod acing. If the prods are located at 5 inches what would be the choice of current to magnetise this a. 550 amps b. 450 amp" between 450 and 550 amps d. always high current to ensure good magnetization 34. Which one of the residual field is most tionable a. circular field b. a longitudinal field C. a vector field poles d. a swinging field 35. Very fine heat treated cracks need be detected in gear tooth blank. The best choice is a. AC wet with nonfluorescent dye b. DC wet with dye AC with fluorescent dye d. AC dry Qn 36 to 40 is to be answ ered with reference to the following Fig, A B C Description : A. 1 inch dia 6 inch long B. 2 inch dia 10 inch long 3 i: ch dia and 12 inch long 36. The order of magnetisation with suitable current values to detect cracks would be a. C-B-A b. B-C-A c.A-B-C d, in any order 37. The surface crack in section would be best detected by a. by head shot with 1200 amps b. by coil shot C. by central conductor by touching the job with prod tips at the end of the job d. by using very large coil with large fill factor 38. The subsurface crack in section C is detected by a. AC wet b. AC dry C. DC wet dry 39. Assume the formula NI = 45,000/ (L/D) and calculate current for 10 turn coil for section C a. 4500 amps b. 2500 amps 1250 amps d. 625 amps 1125 amps. 40. If section C is magnetized with head shot with suitable amps before B & A , a. indications in all sections would be formed b. only defects parallel to the lines of force are formed C. false indications in section B & A can be noticed d. all defects in all sections would appear 541. The term fill factor is referred to a. eddy current testing only b. for head shot for coil shot d. for a coil shot and is ratio of the are of job to the area of the coil 42. A low permeability material is heated to 760 deg.C (curie temp). Now a. the domains would be perfectly oriented to form a permanent magnet b. the domains would be randomly oriented to loose magnetic property domains will not be affected in the case low permeability materials d. at this temperature material is getting magnetised 43. Of the following which one of the casting defect can be detected by MT a. surface sand inclusion b. internal shrinkage c. cold shut d. incomplete penetration 44. A yoke is placed on the weld test plate to detect defects in welds. A well defined indication is formed when using AC. This indication is most probably a. a parallel to the direction of magnetic lines of : b. a surface crack and perpendicular to the direction magnetic lines of force both & b d. yoke not generally used for weld and prods are used 45. The most common failure mechanism associated with sharp fillets, notches etc is a. decarburisation b. overload failure C. fatigue cracking d. knife line attack 46. Materials being repelled by magnet are called ferromagnetic b. paramagnetic diamagnetic d. ferromagnetic 47. A break in the magnetic uniformity of a part is called magnetic discontinuity and is related to sudden change in a. magnetic reluctance b. magnetic capacitance magnetic permeability d. magnetic remnance 48. The lines of force that form a path across the crack in a ring magnet is called a. magnetic lines b. leakage flux C. field strength d. magnetizing force 49. If 1 inch and 2 inches dia. bars were magnetized by passing the same current through them, the magnetic fields would be a. the same for both on the surface b. stronger in the two inch dia. bar weaker in the one inch dia. bar d. stronger in the one inch dia bar 650 Lines of flux are thought to leave a magnet at a. the north pole b. the south pole both north and south poles d. none of the above 51. when testing for fine shallow surface cracks. the preferred MT method would be a. dry AC b. dry DC wet AC d. wet DC 52. What wattage is most commonly used for me rcury vapour bulbs for portable fluorescent magnetic particle inspection a.200watts c.100watts d.75watts 53. Which of the following casting defects is caused by non-uniform cooling resulting in stresses which rupture the surface of the metal a.Shrinkage b. Hot tears c.Porosity 54. Which one of the following properties is true of the lines of force associated with permanent ets a. They do not form closed loops between north and south poles b. They one another They seek paths of least magneti resistance d. Their flux density increases with increasing distance from the poles 55 Which one of the following is not the characteristic of ferro magnetic materials a. The materials are influenced to same degree by the external applied magnetic field like mercury b The material is least influenced by the external applied magnetic field The material is highly influenced by the external applied magnetic field of the above 56. Which one of the following elements is strongly attracted by magnetism a.Zinc b.Wood c.Cobalt d.Mercury 57. The reverse magnetizing force to remove residual magnetism in a given material is a. Retentivity b. Coercive force C. Flux density d.Residual magnetism 58. The limitation in the use of permanent magnets to induce magnetism in ferro-magnetic material is a.It is difficult to magntize large volumes with sufficient field strength b.It is not practical to control the field strength c.Strong magnets may be difficult to remove from the material being magnetized d. all of the above 59. The flux density of magnetism induced by a coil can be controlled by varying a. the coil size b. the current to the coil the number of turns in the coil d. all of the above 760. A tube of 3mm thick, OD 38 mm is magnetized by Head shot, direct conduction with HWDC 1500 amps. What is the field strength at the inner diameter of the surface a. very low b. same as outside surface 50% of b none of the above 61. The 800-1000 amp per 25 mm dia of the part - as a rule of thumb - for current levels is employed in magnetic particle testing. This is applicable to a. only to cylindrical parts longitudinally magnetized b. only to hollow parts longitudinally magnetized e! solid or hollow shaft that are to be circularly magnetized d. weld inspection using prods 62. Full wave three phase rectified AC produced low ripple DC b. used for low power equipment C. produces pulsed DC d. used for inspection of welds with its poor penetrating power 63. The magnetic particle indication is very sharp and well defined. This suggests that th is a a. subsurface seam b. a tight surface crack C. porosity d. a tight subsurface crack 64. The best type of current for the detection of fatigue crack is a. HWRC b. AC C. direct current d. FWRC 65. A cable wrapping procedure to magnetise a part can a. induces a high circular field at a lower current induces high longitudinal field conducts the maxmimum amount of AC as DC d. not to be used especially with dry powder inspection 66. Why are large soft contact areas such as lead or copper braid is used for surfaces for head stock a. to increase the contact area and reduce the possibility of burning the part b. because of their low melting points because they help holding the specimen d. to increase the contact area and flux density 67. The most effective MT method for inspection of large casting is using a. a central conducipr b. multidirectional magnetization C. inspection in many directions d. direct magnetization in many directions 68. The length of the part being magnetized by passing an electric current from one end to the other a. affects the permeability of the part b. changes the strength of the magnetic field does not affect the strength of the magnetic field d. causes the magnetic field to vary 869. When a piece of magnetized job is to be demagnetized the desired direction of placement of the job is a. north south direction east west direction north east direction d. south west direction 70.If it is desired to test a tube using central conductor of copper rod a. the outer surface cracks only be detected b. the inner surface cracks only be detected ! both inner and outer can be detected d. copper conductor is nonferromagnetic and cannot be used in MT 71. If current is assumed to flow from _ve to + ve. which of the following rule need be followed a. Flemmings right hand thumb rule b. Left hand thumb rule Faradays rule d. Amperes formula 72. If current is assumed to flow from which of the following rule need be followed Flemmings right hand thumb rule d. Left hand thumb rule Faradays rule d. Amperes formula 9Magnetic Particle Testing ASME V-Article 7 1) Identify the discontinuity that will be detected most in the following parts by magnetic particle testing? a) Hydrogen flakes in forgings b) Seams in rolled products c) Stringers in bar stocks d) Surface Cracks in Aluminum 2) Which of the following coatings will not interfere with formation of indications in magnetic particle testing? Non-conductive coating, painting thickness less than 50 µm b) Non-conductive coating, painting thickness greater than 50 µm c) Conductive coating, chrome plating thickness less than 50 µm d) Conductive coating, chrome plating thickness grater than 50 µm 3) The choice of magnetic medium for examination of welds and castings would be a) Fluorescent dry powder (b) Non-fluorescent dry powder Fluorescent wet particles d) Non-fluorescent wet particles 4) This procedure allows examination of materials by a Continuous method D) Residual method c) Both Continuous method & Residual method d) Current quick break 5) Continuous method as per this article is a) Dry powders is allowed to settle on part surface and Magnetizing current remains during excess powder is removed b) Magnetizing current is terminated and examination medium applied Magnetizing current remains when dry powders is being applied and while excess powder is removed d) Magnetizing current remains when dry powders is being applied 6) Which of the following is a correct technique for examination of springs for seams and transverse cracks? a) Head shot transverse cracks and central conductor for seams or cracks along the circumference (longitudinal) b) Head shot for seams or cracks along the circumference (longitudinal) and central conductor for transverse cracks c) Head shot in two 90° circumferential position of coil d) Central conductor & coil shot7) The most suited field/flaw gauge standard for verifying field direction and adequacy of field for wet particle inspection is e) Berthold field gauge f) Pie-gauge g) Shims (QQI) System performance plate 8) Which of following is not a correct usage of hall-effect tangential probes with tesla meter? a) For verifying field adequacy of magnetization techniques suitably positioning the probe on the surface of the part perpendicular to the magnetic flux b) For verifying field adequacy of longitudinal magnetization with encircling coils c) For verifying field adequacy with central conductor circular magnetization techniques d) For verifying field adequacy in multi-direction magnetization techniques e) Both & (d) 9) The lifting power of yokes shall be verified at a pole spacing of a) 75 mm b) 100 mm c) 150 mm d' Maximum pole spacing used for examination 10) Demagnetisation of part is required for welds as per this code e) Followed by inspection Any time after post-weld heat treatment g) Any time before post-weld heat-treatment h) Not required if weld is undergoing post-weld heat-treatment 11) If magnetic particle equipment used for prods inspection delivers a maximum output of 2000 amps, the best of five comparative current output levels for calibration would be a) 0,500,1000,1500 & 2000 amps b) 200,750,1000,1500 & 2000 amps c) 300,600,900,1250 & 1750 amps d) 500,1000,1250, 1750 & 2000 amps 12) If fixed multi-turn coil is used for inspection of cylindrical parts as per this code a The part is positioned near the ID surface of the coil b) The part is positioned on the axis of the coil (center)I c) The part is positioned near the ID surface of the coil, only if the dia of the part is within 10% of coil opening d) Any one of the above12) The yoke technique as per this code is employed to a) Detect surface discontinuities b) Detect near-surface discontinuities c) Detect both surface and near-surface discontinuities Detect surface discontinuities that are open 13) Linear indication is a) Length equal to width b) Length equal to 3 times the width Length greater than 3 times the width d) Any indication greater than 2mm 14) Which of the following produces a false indication? a) Machining marks & Localized surface irregularity b) Permeability difference c) Magnetic writing d) Keyways & internal splines 15) According to this code a technique sheet is required for a) Prods inspection b) Yoke techniques c) Coil technique d) Multi-direction magnetization techniqueMT Nov 05 Sample acceptance EVALUATION OF INDICATIONS Mechanical discontinuities at the surface are revealed by the retention of dry powder or powder suspensions. Certain metallurgical discontinuities, and magnetic permeability variations may produce similar indications which are considered as `non-relevant'. Hence all indications are not necessarily defects. Relevant indications are indications which result from imperfections. Any indications that is believed to be shall be examined by the same or other non-destructive methods whether or not actual defects are present. Surface conditioning precedes the re-examination. After an indication has been verified to be non-relevant, it is not necessary to reinvestigate repetitive non-relevant indications of the same type. Linear indications are indications in which the length is more than three times the width. Rounded indications are indications which are circular or elliptical with the length equal to or less than three times the width. ACCEPTANCE STANDARDS Round or elliptical indications with major dimensions greater than 1.6 mm shall be considered as relevant imperfection. Non-relevant indications that would mask defects are unacceptable. Rounded indications with dimensions greater than 5 mm are not acceptable. Any Cracks, in-complete pentration & lack of fusion in welds are unacceptable Any other linear indications greater than 6 mm are not acceptable REPORTING: The reporting of the results of examination shall be duly signed by a level-II or Level-III personnel.ASNT (Nov.2005) 1. Give the definition of the reluctance R of an magnetic circuit of length L, and area S and magnetic permeability a. C. R d. 2. Which of the following grades of steel lends itself most favourably to the detection of subsurface defects 172.41 a. highly alloyed steel nonalloyed steel with low carbon content C. slightly alloyed steel d. nonallyed with high carbon content 3. When an AC current passes through a cylindrical conductor, the magnetic field decreases from periphery towards the center this reduction is fast at the start and then slow D. this reduction is slow at the start and then fast C. the reduction is linear d. Neither a or b or the value of magnetic field is constant 4. The detection of deep lying defectsin thick weldments, 2" below the surface is a. very similar to the detection of wet cracks b. not difficult if the defect is attributable to fine porosity C. simple if the defect width ca be enlarged very improbabke 5. Which one of them is not recommended in MT a. longitudinal b. circular C. vector d parallel 6. The patterns of iron powder sprinkled on a paper placed over a bar magnet are called a. gield survey b. magnetometer C, flux indication d. magnetograph 7. How is the solid content of a suspension of magnetic particles measured a. by weighing the suspension b. by soaking the solids in benzoil or Xylene by measuring the solids that settle out of the suspension e. by measuring the pull of the magnet f. 18. Magnetic flux is a term that relates to a. describing the direction of current flow in an electromagnet b. the manner in which magnetism flows through space the number of lines of force associated with magnetic field d. permanent magnets only 9. The value of permeability is a. a fixed value depending upon the type of material' b. between 1 and 100 for all ferromagnetic materials a variable d. dependant on the amount of magnetizing force necessary to overcome saturation 10, The SI unit of the remnance or residula magnetism a. Gauss b Tesla C. Maxwell d. Oersted 11. Which of the following grades of steel lends itself most favourably to the detection of defects by MT a. highly alloyed steel b. slightly alloyed steel C unalloyed low carbon steel d. unalloyed high carbon steel 12. While demagnetizing a part, which is circularly magnetised part may have no external poles and may as no apparent indication of the presence of an internal field and hence a. it is often better to convert the circular field to a longitudinal field no special precautions are necessary C. only heating the component will achieve the demagnetization d. it can never ne demagnetized 13. The best shape.of the magnetic particles for the dry powder method is a. globular b. flat C. long and slender d a mixture of a and C of the above 14. The unit for permeability is a. Gauss / Oersted b. Tesla /amp/mtre C. Hendry/ m all of the above 15. Maxwell is equal to a 10 -8 weber b. 10 8 weber C. 10 -8 Tesla d. 10 8 Tesla 16. Which current may be convenient to effect demagnetisation AC b, DC C. HWRC d. FWRC 217. Which of the following magnetic fields will have the most effect on other material and equipment affected by external flux leakage and as such will more than likely require demagnetisation? Longential Circular Circumferential Longitudinal 18, As the depth of a detectable flaw increases below the surface the powder pattern will become which of the following? Clear and narrow Diffuse and wider Clear and wider Diffuse and narrow 19, In an attempt to depth a crack found with magnetic particle inspection which other method of NDT could be used? Liquid penetrant Leak testing Grinding to clear 20. Non metallic inclusions can also be found with magnetic particle inspection as well as cracks. This is due to a change in what property of the inclusion in relation to the parent materials? Conductivity Flux leakage Hysteresis Permeability 21. A fault on the surface of a rolled bar is present due to blowholes elongating along the length of the bar. How would this fault be termed? Underfill Seam Roke Crack 122. Which of the following techniques would be considered to be the most sensitive for detection of surface breaking faults on materials with high retentivity if the length of time taken to cary out the inspection is of no consequence? Continuous - wet Residual - wet Continuous - dry Residual - dry 23. When magnetic particles from a wet magnetic ink become stranded in drainage lines such as the toe of a weld when the carrier fluid drains away, what type of indication can build up? False indication True - non relevant indication True - relevant indication Crack - line indication 24. Which of the following could give rise to true non-relevant magnetic particle indications? Areas of cold work Both areas of work and prazed joints All of them 2AMMETER WAVE FORM RELATIONSHIP READING A.C. + Peak Time TT Inv Straight D.C. + I mean I I peok = mean Time F.W.D.C. + I Mean Peok I mean I peak = TT 2 I mean Time +1 H.W.D.C. I Peak Mean I Time mean I peak = mean Fig. Relationship between RMS and peak values of current. Current is uniformly distributed over section of the component. The required current is proportional to the peri- meter. There is no set formula for fixing the magnitude of the current, however experience has shown that guide lines given in Table VIII is adequate to detect discontinuities of interest.5330.16 4. PENETRATION Various tests conclusively prove that the ac method is more sensitive than dc or hwdc, in showing surface discontinuities. Figure 2-24 compares the abilities of various methods. The illustration plots amperage against depth of discontinuity. This experi- ment was performed, using the test specimen shown to the right in Figure 2-24, and recording the lowest amperage which gave a minimum threshold indication at various discontinuity depths. 208 CURRENT REQUIREMENTS 1. GENERAL The required amount of magnetizing current is affected by the permeability of the metal, the shape and thickness of the article, and the type of discontinuity sought. The length of an article does not affect the current requirement, because the current flow in a uniform cross section is uniform throughout the length of the article. The electrical resistance (reluctance) of the article, however, will increase with length, therefore requiring more energy to develop the same amperage (or field) through the specimen. When a specimen is not uniform in section, it is necessary to use one value of current for the thinner sections and a second, third, or more values of currents for heavier sections. It is always proper to use the smaller current value 1000 AC AC DC DC WET DRY WET DRY SURGE 800 DC-DRY HW DRY 600 AMPERES CURRENT 400 CENTRAL CONDUCTOR 200 5" DIA RING WITH DRILLED HOLES 0 0 2 4 6 8 10 12 RELATIVE DEPTH OF DISCONTINUITY Figure 2-24. Threshold Sensitivities of Various Metals 2-24