EDDY CURRENT TESTING | NDT TRAINING | ESL INDUSTRIAL SUPPORT SERVICES

EDDY CURRENT TESTING

QUESTION BANK

1.In a feed through encircling coil eddy current system, what would be the purpose of running a calibration defect several times but in various positions (such as top, bottom, left and right)?

  1. To check the phase selectivity
  2. To ensure proper centring of the material in the test coil
  3. To select the modulation analysis setting
  4. To select the proper operation speed

2.In a feed through encircling coil eddy current system, a calibration standard may be used to:

  1. Insure repeatability of the setup
  2. Calibrate the approximate depth of the detectable flaws
  3. Both a and b
  4. Measure the test frequency

3.A calibration standard may be used with a spinning probe eddy current instrument to:

  1. Produce an indication relative to the depth of the flaw
  2. Check the instrument for reliability and freedom from drift
  3. Check probe coil for possible damage
  4. All of the above

4.Spinning probe type eddy-type eddy current instruments are most useful in:

  1. Detection of surface and subsurface inclusions
  2. Detection of surface defects such as overlaps and seams
  3. Detection of internal piping or burst
  4. All of the above

5.A product can be viewed in terms of electrical magnetic effects. A diameter change of the product in an encircling coil is:

  1. An electrical effect
  2. A conductivity effect
  3. A magnetic effect
  4. All of the above

6.In figure 9, AC flowing through a primary coil set-up a magnetic field and causes a flow of eddy currents in the rod. The voltage of the secondary coil is dependent upon:

et1

  1. These eddy currents
  2. The primary coil
  3. The generator
  4. All of the above

7.Which of the following is not a method that may be used to improve the signal-to-noise ratio?

  1. Change to test frequency that will decrease the noise
  2. Increase the amplification of the test instrument
  3. Improve the fill factor
  4. Add filter circuits to the instruments

8.In eddy current testing, the theoretical maximum testing speed is determined by the:

  1. Magnetic flux density
  2. Testing frequency
  3. Conveyor drive
  4. Test coil impedance

9.In eddy current testing of ferromagnetic materials, the dc saturating field may be provided by :

  1. An encircling solenoid
  2. A magnetic yoke
  3. Both a and b
  4. None of the above

10.Which of the following is a property of eddy currents induced in a conductor by an encircling coil?

  1. The magnitude of eddy current flow is large compared to the current flow in the coil
  2. The eddy current flow is affected by permeability variation in the samples
  3. The eddy current flow dissipates no power in the conductor
  4. None of the above

11.Which of the following is a property of eddy currents induced in a homogeneous conductor by an encircling coil?

  1. They are weakest on the conductor surface
  2. The phase of the eddy currents varies through out the conductor
  3. They travel in straight lines
  4. They are maximum along the coil axis.

12.Which factor does not affect the phase shift between the transmitted signal and the reflected signal for a reflection type coil(assuming the part is nonferromagnetic)?

  1. The conductivity of the sample
  2. The magnitude of the transmitted signal
  3. The signal of the sample
  4. The presence of defects in the sample

13.Lift-off certainly reduces the amplitude of the flux leakage signal. The other significant effect it has on the signal is a change in:

  1. Phase
  2. Frequency
  3. Increasing lift-off which reduces the apparent width of the defect
  4. None of the above

14.The tubular product parameter having the greatest influence on the flux density of the magnetic field in the part (assuming the magnetizing force, H, remains constant)is the :

  1. Surface roughness of the product
  2. Diameter of the product
  3. Wall thickness of the product
  4. Length of the product

15.Any handling of equipment used in an eddy current system must take into consideration:

  1. The operator ‘s abilities
  2. The use of the product being tested
  3. Speed, frequency of test, sorting speed, and physical control of the product
  4. All of the above

16.An eddy current system lends itself to quality ratings such as “Quality Number” where the product being inspected:

  1. Is not defective
  2. Does not allow defective areas to be removed
  3. Is of inferior quality
  4. Has inconsistent quality

17.When inspecting material with eddy currents in an automatic handling system, it is advisable to calibrate and adjust the sensitivity levels to:

  1. Some electroic source
  2. Another NDT method
  3. An NBS standard
  4. An actual testpart being inspected

18.A distinct advantage of using handling equipment in an eddy current test system is to reduce the error caused by:

  1. Instrument drift
  2. Lift-off
  3. Skin effect
  4. All of the above
  5. None of the above

19.Decreased coupling or fill factor results in decreased test sensitivity because:

  1. Reduced coupling between the driver coil and the specimen induces less eddy current flow in the specimen
  2. Reduced coupling between the specimen and the pickup coil results in smaller voltages across the pickup coil
  3. Electrical circuits designed to provide fill factor compensation may prove to be inadequate, depending upon the extent of fill factor loss
  4. All of the above

20.Why is it desirable to hold the factor or lift-off constant?

  1. To avoid arcing between the coil and the specimen
  2. To minimize tester output signal changes that are not relevant to conditions with in the specimen to be tested.
  3. A fill factor or lift-off change will shift the operating frequency
  4. To minimize the load on the constant current ac excitation circuits

21.The reactance component is decreased by placing a conducting object in the coil’s electromagnetic field. Why is this so?

  1. The secondary field is exactly in phase with the primary field
  2. The secondary field is at precisely 90 degrees with the primary field
  3. The phase angle between the two field components is always greater than 90 degrees which partially cances the primary field
  4. The secondary field is 180 degrees out of phase with the primary field which causes a large phase shift

22Test coils may be shielded with conducting material or magnetic material to:

  1. Shape field
  2. Increase sensitivity
  3. Increase resolution
  4. All of the above
  5. None of the above

23.When a magnetic bar is placed in the coil’s electromagnetic field,the coil’s reactance is increased. What causes this phenomena?

  1. The coil becomes magnetic ally saturated
  2. The permeability raises the inductance of the test coil
  3. The magnetic test sample’s conductivity increases the reactance value of the coil
  4. This effect is described mathematically by thr equation B/H=μ

24.When an excitation voltage is applied to a primary winding, only the magnetic flux is in phase and the secondary magnetic flux is minor. When a test object is inserted in this coil, what action takes place?

  1. The object gets hot and no information is available
  2. Insertion of the object cancels all information
  3. The insertion of the test object intensifies the secondary magnetic flux producing a new total magnetic flux which can be used to supply test information
  4. By subtracting the primary voltage from the secondary voltage, the net voltage is obtained

25.The test coil excitation current should be held constant so that the test piece information obtained by an eddy current system will:

  1. Contain only flaw information and not indicate variations in magnetic field strength
  2. Not contain signals generated by cross talk
  3. Not contain electrical noise
  4. All of the above

26.Eddy currents flowing in the test object at any depth produce magnetic fields at greater depths, which oppose the primary field, thus breducing its effect and causing what kind of change in current flow as depth increases?

  1. A decrease
  2. An increase
  3. A frequency change
  4. None of the above

27.Skin effect causes eddy currents to tend to flow near the surface of the test piece. Which of the following factors alter the skin effect?

  1. Testing frequency
  2. Test piece temperature
  3. Test piece hardness
  4. Test piece permeability
  5. None of the above

28.Which of the following is not a common undesirable effect to the test caused by the testing environment?

  1. Temperature variation
  2. Crack in test sample
  3. Test object making contact with test coil
  4. Foreign object in the test coil field
  5. Test coil vibration

39.There is one function that responds to variations in eddy current flaw and magnetic field conditions. This function actually produces the output signal from the coil. What is this function?

  1. Phasing
  2. Resistance
  3. Reactance
  4. Impedance

30.The inductive reactance of a test coil, which is one of the most importance impedance quantities, depends upon which of the following?

  1. Frequency, coil inductance, coil resistance
  2. Coil inductance only
  3. Coil resistance and coil inductance only
  4. Frequency and coil resistance only
  5. Frequency and coil inductance only

31.An ac current produces eddy currents in a test object. The vector Hp represents the secondary ac field in the test piece. What function occurs to produce a workable test situation? (See figure 10)et2

  1. Changes in the test specimen such as a crack, metallurgical and dimensional change alter the secondary field phase and amplitude
  2. The primary ac current must be 60 cycles to produce this effect
  3. A temperature raise in the specimen
  4. A mismatch of the Hp and Hs fields produces a change in the output

32.To separate cracks and diameter effects for steel cylinders, the optimum frequencies correspond to f/fg ratios of less than (see figure 11)

et3

  1. 10
  2. 15
  3. 50
  4. 100
  5. 150

33.Thin –walled tubes should be tested for cracks, alloy or wall thickness at frequency ratios between(see Figure 12):

et4

  1. 0.1 and 0.4
  2. 0.4 and 2.4
  3. 2.4 and 4.0
  4. 4.0 and 10

34.Figure 13 indicates that the largest eddy current indicates from subsurface cracks will occur when the frequency ratio(f/fg) is:

et5

  1. 5 or less
  2. 15
  3. 50
  4. 150 or more

 

35.Figure 13 indicates that the magnitude of a signal from a surface crack will increase when the frequency ratio(f/fg):

  1. Remains the same
  2. Decreases
  3. Increases
  4. None of the above

36.Figure 14 indicates that when inspecting for surface cracks in nonferromagnetic cylinders, the optimum frequency ratio (f/fg) is between :

et6

  1. 5 and 10
  2. 10 and 50
  3. 50 and 100
  4. 100 and 150

37.An operating frequency of 100 khz will have the deepest penetration in:

  1. Titanium
  2. Copper
  3. Stainless steel
  4. Aluminum

38.As the operating frequency is increased, the impedance of the empty coil:

  1. Increases
  2. Decreases
  3. Remains the same
  4. None of the above

39.Disadvantage of using a surface probe coil for the inspection of small diameter tubing include:

  1. Inability to detect small discontinuities
  2. Slow inspection speed
  3. Inherent mechanical problem
  4. Both a and c
  5. Both b and c

40.Differntial coil system can be of which of the following types? (See figure 15)

et7

  1. Sketch no. 1
  2. Sketch no. 2
  3. Sketch no. 3
  4. All of the above
  5. Both a and b

EDDY CURRENT QB 1

ANSWERS

Q.NO ANSWERS Q.NO ANSWERS
1 2 21 3
2 1 22 4
3 4 23 2
4 1 24 3
5 3 25 1
6 4 26 1
7 2 27 5
8 2 28 2
9 3 29 4
10 2 30 5
11 2 31 1
12 2 32 1
13 2 33 2
14 3 34 1
15 4 35 2
16 2 36 2
17 4 37 3
18 2 38 1
19 4 39 5
20 2 40 4

 

 

 

 

Visual Testing | VT | Non Deatructive testing | VT Training in Trichy

 

VISUAL TESTING

 

Visual Testing:

Introduction:

Based on the principle of illuminating the object by light in the visible region of the electro magnetic wave spectrum.

One of the first, natural, methods of testing of anything we use is visual testing.visual testingPrerequisites:

  • Eye – The sensor;
  • Light – The probing medium.

Requirements:

  • Testing of the vision of the inspector, measurement with a light meter of the light falling on the specimen and establishing the actual ability to see the area being inspected.
  • Refer the code for the specifications.

Eye:

visual testing

Calibration of Eye:

  • Near Vision Acuity;
  • Colour blindness.

Near Vision Acuity Chart:

visual testingIshihara Chart:

visual testingLighting:

visual testingSteps:

  • Clean the test object sufficient enough to observe the details.
  • Keep it in a well illuminated space – generally 800 – 1000 lux.
  • Inspect the object by eye or by light sensitive devices such as photocells.

Aids for visual testing:

  • Mechanical aids;
  • Optical aids.

Mechanical Aids:

  • Measuring rules & tapes;
  • Calipers & micrometers;
  • Squares and angle measuring devices;
  • Thread, pitch and thickness gages;
  • Level gages (liquid & laser) and plumb lines;
  • A variety of weld gages.

Scale:visual testing

Parallax Error:

visual testing

Correct Usage:

visual testing

PI Tape:

visual testing

Vernier Scale:

visual testingMicrometer:

visual testingWeld Gauge:

visual testingOptical aids for visual testing:

  • Mirrors (especially small, angled mirrors);
  • Magnifying glasses, eye loupes, multilens magnifiers, measuring magnifiers;
  • Microscopes (optical and electron);
  • Optical flats (for surface flatness measurement);
  • Borescopes and fiber optic borescopes;
  • Optical comparators;
  • Photographic records;

Microscope:

visual testingMagnifying Lens:

visual testingOptical aids for visual testing:

  • Closed circuit television (CCTV) systems (alone and coupled to borescopes/microscopes);
  • Machine vision systems;
  • Positioning and transport systems (often used with CCTV systems);
  • Image enhancement (computer analysis and enhancement).

Enhancement Techniques in  visual testing:

  • 1. Microscope.
  • 2. Borescope.
  • 3. Endoscope.
  • 4. Flexible Fibre-Optic Borescope (Flexiscope).
  • 5. Telescope.
  • 6. Holography.

Application in visual testing:

  • Everywhere and anywhere.
  • Also before conducting any NDT.
  • Least expensive of all NDT methods.
  • Permanent records are possible with the help of camera.

Advantages of  visual testing:

  • Simplicity;
  • Rapidity;
  • Low cost;
  • Minimal training;
  • Minimal equipment requirements;
  • Ability to be performed while the specimen is being used or processed.
  • In many cases will eliminate the need for the need for more sophisticated NDT.

Limitation of visual testing:

  • Can be applied to surface discontinuities only.
  • Least sensitive of all NDT methods.
  • The poor and variable resolution of the eye, fatigue of the inspector, distractions and hence heavily dependant on the inspector.
  • In some cases cost of the visual aids (equipments) can be very high.

 

WELDER TRAINING IN TRICHY | ESL SCHOOL OF WELDING

 

Welder Training

TRAINING MODULES OF ESL:

  • SMAW – ARC (1G to 4G)
  • GTAW – TIG (1G to 6G)
  • GMAW – MIG (1G to 4G)

WHAT IS WELDING?

Welding is nothing more than the art of joining metals together. It is one of the most valuable technologies that played a huge part in the industrial revolution, and is the back bone to the world’s militaries. Welding today is comprised of three main ingredients which are required to join metals together.

WPQ (Welder Performance Qualification)

WPQ will be performed as per ASME Sec IX/AWS D1.1 code with welder ID continuity record will be provided

ARC WELDING:

ARC Welding is a slang term commonly used for Shielded Metal Arc Welding or “SMAW”. Arc welding is the most basic and common type of welding processes used. It is also the first process learned in any welding school. Arc is the most trouble free of all of the welding processes and is the fundamental basis for all the skills needed to learn how to weld.

TIG WELDING:

TIG Welding is also a slang term commonly used for Gas Tungsten Arc Welding or “GTAW”. TIG welding also goes by the term HeliArc welding. TIG welding is the most difficult of the processes to learn, and is the most versatile when it comes to different metals. This process is slow but when done right it produces the highest quality weld! TIG welding is mostly used for critical weld joints, welding metals other than common steel, and where precise, small welds are needed.

MIG WELDING

MIG Welding is a slang term that stands for Metal Inert Gas Welding, the proper name is Gas Metal Arc Welding or “GMAW”, and it is also commonly referred to as “Wire Wheel Welding” by Unions. MIG Welding is commonly used in shops and factories. It is a high production welding process that is mostly used indoors.

POSITION REQUIRED:

PROCESS MATERIAL JOINT POSITION
SMAW

(ARC)

 PLATE GROOVE/

FILLET

 1G TO 4G
GTAW

(TIG)

 PIPE/ TUBE GROOVE/

FILLET

 1G TO 6G
GMAW

(MIG)

 PLATE GROOVE/

FILLET

 1G TO 4G

 

Welder Training Welder Training Welder Training Welder Training

 

 

 

Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training Welder Training

API 510 Questions | ESL Industrial Suppport Services | API Training Institute

 

API 510 Questions

 

  1. A PQR was qualified in SG position using a new welder. But production welding is to be done by   the same welder in 3G position. Which of the following are applicable as a minimum?
  1. Both procedure and welder shall be re-qualified in 2G position.
  2. The qualified procedure can be used, only welder needs to be re-qualified in 3G position.
  3. The welder is qualified, but the procedure needs re­-qualification.
  4. Both procedure and welder need not be re-qualified.
  1. A procedure is required with preheat temp = 2S0oF. Two WPS were made based on this PQR. All other parameters being same WPS (A) showed preheat temp = 280°F and WPS (B) showed preheat temp = 140°F, will you:
  1. Reject (A) & (B)
  2. Accept (A) only
  3. Accept (B) only
  4. Accept both
  1. In a certain PQR for SMAW, the electrodes used for all passes were of AWS classification (E7018). Corresponding WPS also showed filler materials as E 7018. Now the manufacturer proposes to change the filler material in WPS to E 701S. Will you ask manufacturer to:
  1. Quality new PQR with E 7015 electrodes.
  2. Revise only WPS showing the change from E 7018 to E7015 and submit WPS as a new    revision.
  3. Revise only the PQR showing the change and resubmit for approval.
  4. Revise both WPS and PQR showing the change and resubmit for approval.
  1. A PQR in GTAW process was qualified with PWHT with A 516 grade 70 materials, ¾” thick. The thickness for production welds is 1.0”, but without PWHT. The manufacturer claims that same PQR will be O.K. What is your assessment?
  1. It qualifies required conditions hence no new PQR is required.
  2. It qualifies thickness but not It does not qualify “No PWHT” condition, hence new PQR is   required.
  3. It qualifies “no PWHT” condition, but not thickness. New PQR is required.
  4. It does not qualify both thickness as well as “No PWHT” – condition, hence new PQR is    required. ­
  1. For 515 grade 60 material, the following results were obtained for two tensile test specimen during   a PQR qualification.

Specimen T1: failed in B.M. at 57,400 psi

Specimen T2: failed in weld metal, at 59,500 psi

Your assessment is:

  1. PQR test is OK since both are within acceptance criteria
  2. PQR test is rejected as both T1 and T2 are not within the acceptance criteria
  3. PQR in rejected because T1 is OK but T2 has failed
  4. PQR in rejected because T1 is failed thoughT2 is OK
  1. A procedure is qualified with Base metal THK. = 20mm. Two WPS were made based on this PQR. Other parameters being same, WPS (A) showed Base Metal Thk. = 38 mm and WPS (B) showed Base Metal Thk. = 6mm.  

Your assessment is

  1. Reject (A) & (B)
  2. Accept (A) only
  3. Accept (B) only
  4. Accept both
  1. A welder has made 25 SMAW groove welds, but the guided bend test for the welder’s qualification was never performed. In order to avoid cutting out all of the production welds made by this welder, which of the following minimum steps would be taken to validate the qualification?
  1. Radiograph the welder’s first production weld and accept the qualification based on acceptable weld quality by radiography.
  2. There is no alternative to qualifying a welder by the guided bend test.
  3. Have the welder prepare a test coupon and have the bend test done on that. If bend test is okay,    accept the welds already made.
  4. Radiograph all 25 welds, regardless of the governing specifications for sample selection.
  1. In a radiographic examination of butt weld (Thk= 3.5 in.) the Geometric un-sharpness shall not exceed?
  1. 0.02″
  2. 0.04″
  3. 0.03″
  4. None of above
  1. Select suitable Hole Type (Source Side) penetrameter for following weld joint:

Base Mertal Thk. = 7/8”

Backing Strip Thk. = 3/16”

Weld Re-enforcement Thk. = 1/8”

  1. No. 20
  2. No. 25
  3. No. 30
  4. None of the above

10. If type of penetrameter in above question is changed to wire type what shall be the wire designation                                                 (wire diameter In  Inch)?

  1. 0.025 dia. (No.10)
  2. 0.016 dia. (No. 8)
  3. 0.032 dia. (No.11)
  4. None of the above

11. For steel plates and welds to be checked by LPI what shall be the penetration time for the Penetrant?

  1. 10 min for weld, 5 min for plate
  2. 5 min for both
  3. 10 min for both
  4. 5 min for weld, 10 min for plate

12. After applying the developer the examiner checked four welds for surface defects after following period,                                       weld A after 5 minute,weld B after 10 minutes, weld C was checked after 30 minutes and welds D                                                       after 65 minutes. Which of the welds were checked wrongly?

  1. Weld A and B
  2. Weld C and D
  3. Weld D only
  4. Weld A and D

13. For MT examination by Prod Technique the spacing between prods shall be between?

  1. 4 inch to 12 inch
  2. 4 inch to 10 inch
  3. 3 inch to 10 inch
  4. 3 inch to 8 inch

14. Calculate estimated inspection period for external and internal inspection for a vessel whose remaining                                         life is estimated as 12 years?

  1. Internal = 6 years, external = 10 years
  2. Internal = 6 years, external = 5 years
  3. Internal = 5 years, external = 10 years
  4. None of the above

15.As per WPS the material used is SAS16 Gr.70 and the electrode used is E-7018. What are the P. No. and F No.?

  1. 1 and 4
  2. 4 and 1
  3. 2 and 4
  4. 4 and 2

 

­

 

­Q. NO. ANSWER
1 4
2 2
3 2
4 2
5 3
6 4
7 1
8 2
9 2
10 4
11 4
12 4
13 4
14 2
15 1

 

 

 

Eddy Current Question Bank | ESL Industrial Support Services

EDDY CURRENT

1. In a feed through encircling coil eddy current system, what would be the purpose of running a calibration defect several times but in various positions (such as top, bottom, left and right)?

a.To check the phase selectivity

b.To ensure proper centring of the material in the test coil

c.To select the modulation analysis setting

d.To select the proper operation speed

2.In a feed through encircling coil eddy current system, a calibration standard may be used to:

a.Insure repeatability of the setup

b.Calibrate the approximate depth of the detectable flaws

c.Both a and b

d.Measure the test frequency

3.A calibration standard may be used with a spinning probe eddy current instrument to:

a.Produce an indication relative to the depth of the flaw

b.Check the instrument for reliability and freedom from drift

c.Check probe coil for possible damage

d.All of the above

4.Spinning probe type eddy-type eddy current instruments are most useful in:

a.Detection of surface and subsurface inclusions

b.Detection of surface defects such as overlaps and seams

c.Detection of internal piping or burst

d.All of the above

5.A product can be viewed in terms of electrical magnetic effects. A diameter change of the product in an encircling coil is:

a.An electrical effect

b.A conductivity effect

c.A magnetic effect

d.All of the above

6.In figure 9, AC flowing through a primary coil set-up a magnetic field and causes a flow of eddy currents in the rod. The voltage of the secondary coil is dependent upon:

a.These eddy currents

b.The primary coil

c.The generator

d.All of the above

7.Which of the following is not a method that may be used to improve the signal-to-noise ratio?

a.Change to test frequency that will decrease the noise

b.Increase the amplification of the test instrument

c.Improve the fill factor

d.Add filter circuits to the instruments

8.In eddy current testing, the theoretical maximum testing speed is determined by the:

a.Magnetic flux density

b.Testing frequency

c.Conveyor drive

d.Test coil impedance

9.In eddy current testing of ferromagnetic materials, the dc saturating field may be provided by :

a.An encircling solenoid

b.A magnetic yoke

c.Both a and b

d.None of the above

10.Which of the following is a property of eddy currents induced in a conductor by an encircling coil?

a.The magnitude of eddy current flow is large compared to the current flow in the coil

b.The eddy current flow is affected by permeability variation in the samples

c.The eddy current flow dissipates no power in the conductor

d.None of the above

11.Which of the following is a property of eddy currents induced in a homogeneous conductor by an encircling coil?

a.They are weakest on the conductor surface

b.The phase of the eddy currents varies through out the conductor

c.They travel in straight lines

d.They are maximum along the coil axis.

12.Which factor does not affect the phase shift between the transmitted signal and the reflected signal for a reflection type coil(assuming the part is nonferromagnetic)?

a.The conductivity of the sample

b.The magnitude of the transmitted signal

c.The signal of the sample

d.The presence of defects in the sample

13.Lift-off certainly reduces the amplitude of the flux leakage signal. The other significant effect it has on the signal is a change in:

a.Phase

b.Frequency

c.Increasing lift-off which reduces the apparent width of the defect

d.None of the above

14.The tubular product parameter having the greatest influence on the flux density of the magnetic field in the part (assuming the magnetizing force, H, remains constant)is the :

a.Surface roughness of the product

b.Diameter of the product

c.Wall thickness of the product

d.Length of the product

15.Any handling of equipment used in an eddy current system must take into consideration:

a.The operator ‘s abilities

b.The use of the product being tested

c.Speed, frequency of test, sorting speed, and physical control of the product

d.All of the above

16An eddy current system lends itself to quality ratings such as “Quality Number” where the product being inspected:

a.Is not defective

b.Does not allow defective areas to be removed

c.Is of inferior quality

d.Has inconsistent quality

17.When inspecting material with eddy currents in an automatic handling system, it is advisable to calibrate and adjust the sensitivity levels to:

a.Some electroic source

b.Another NDT method

c.An NBS standard

d.An actual testpart being inspected

18.A distinct advantage of using handling equipment in an eddy current test system is to reduce the error caused by:

a.Instrument drift

b.Lift-off

c.Skin effect

d.All of the above

e.None of the above

19.Decreased coupling or fill factor results in decreased test sensitivity because:

a.Reduced coupling between the driver coil and the specimen induces less eddy current flow in the specimen

b.Reduced coupling between the specimen and the pickup coil results in smaller voltages across the pickup coil

c.Electrical circuits designed to provide fill factor compensation may prove to be inadequate, depending upon the extent of fill factor loss

d.All of the above

20.Why is it desirable to hold the factor or lift-off constant?

a.To avoid arcing between the coil and the specimen

b.To minimize tester output signal changes that are not relevant to conditions with in the specimen to be tested.

c.A fill factor or lift-off change will shift the operating frequency

d.To minimize the load on the constant current ac excitation circuits

21.The reactance component is decreased by placing a conducting object in the coil’s electromagnetic field. Why is this so?

a.The secondary field is exactly in phase with the primary field

b.The secondary field is at precisely 90 degrees with the primary field

c.The phase angle between the two field components is always greater than 90 degrees which partially cances the primary field

d.The secondary field is 180 degrees out of phase with the primary field which causes a large phase shift

22.Test coils may be shielded with conducting material or magnetic material to:

a.Shape field

b.Increase sensitivity

c.Increase resolution

d.All of the above

e.None of the above

23.When a magnetic bar is placed in the coil’s electromagnetic field,the coil’s reactance is increased. What causes this phenomena?

a.The coil becomes magnetic ally saturated

b.The permeability raises the inductance of the test coil

c.The magnetic test sample’s conductivity increases the reactance value of the coil

d.This effect is described mathematically by thr equation B/H=μ

24.When an excitation voltage is applied to a primary winding, only the magnetic flux is in phase and the secondary magnetic flux is minor. When a test object is inserted in this coil, what action takes place?

a.The object gets hot and no information is available

b.Insertion of the object cancels all information

c.The insertion of the test object intensifies the secondary magnetic flux producing a new total magnetic flux which can be used to supply test information

d.By subtracting the primary voltage from the secondary voltage, the net voltage is obtained

25.The test coil excitation current should be held constant so that the test piece information obtained by an eddy current system will:

a.Contain only flaw information and not indicate variations in magnetic field strength

b.Not contain signals generated by cross talk

c.Not contain electrical noise

d.All of the above

26.Eddy currents flowing in the test object at any depth produce magnetic fields at greater depths, which oppose the primary field, thus breducing its effect and causing what kind of change in current flow as depth increases?

a.A decrease

b.An increase

c.A frequency change

d.None of the above

27.Skin effect causes eddy currents to tend to flow near the surface of the test piece. Which of the following factors alter the skin effect?

a.Testing frequency

b.Test piece temperature

c.Test piece hardness

d.Test piece permeability

e.None of the above

28.Which of the following is not a common undesirable effect to the test caused by the testing environment?

a.Temperature variation

b.Crack in test sample

c.Test object making contact with test coil

d.Foreign object in the test coil field

e.Test coil vibration

29.There is one function that responds to variations in eddy current flaw and magnetic field conditions. This function actually produces the output signal from the coil. What is this function?

a.Phasing

b.Resistance

c.Reactance

d.Impedance

30.The inductive reactance of a test coil, which is one of the most importance impedance quantities, depends upon which of the following?

a.Frequency, coil inductance, coil resistance

b.Coil inductance only

c.Coil resistance and coil inductance only

d.Frequency and coil resistance only

e.Frequency and coil inductance only

31.An ac current produces eddy currents in a test object. The vector Hp represents the secondary ac field in the test piece. What function occurs to produce a workable test situation? (See figure 10)

a.Changes in the test specimen such as a crack, metallurgical and dimensional change alter the secondary field phase and amplitude

b.The primary ac current must be 60 cycles to produce this effect

c.A temperature raise in the specimen

d.A mismatch of the Hp and Hs fields produces a change in the output

32.To separate cracks and diameter effects for steel cylinders, the optimum frequencies correspond to f/fg ratios of less than (see figure 11)

a.10

b.15

c.50

d.100

e.150

33.Thin –walled tubes should be tested for cracks, alloy or wall thickness at frequency ratios between(see Figure 12):

a.0.1 and 0.4

b.0.4 and 2.4

c.2.4 and 4.0

d.4.0 and 10

34.Figure 13 indicates that the largest eddy current indicates from subsurface cracks will occur when the frequency ratio(f/fg) is:

a.5 or less

b.15

c.50

d.150 or more

35.Figure 13 indicates that the magnitude of a signal from a surface crack will increase when the frequency ratio(f/fg):

a.Remains the same

b.Decreases

c.Increases

d.None of the above

36.Figure 14 indicates that when inspecting for surface cracks in nonferromagnetic cylinders, the optimum frequency ratio (f/fg) is between :

a.5 and 10

b.10 and 50

c.50 and 100

d.100 and 150

37.An operating frequency of 100 khz will have the deepest penetration in:

a.Titanium

b.Copper

c.Stainless steel

d.Aluminum

38.As the operating frequency is increased, the impedance of the empty coil:

a.Increases

b.Decreases

c.Remains the same

d.None of the above

39.Disadvantage of using a surface probe coil for the inspection of small diameter tubing include:

a.Inability to detect small discontinuities

b.Slow inspection speed

c.Inherent mechanical problem

d.Both a and c

e.Both b and c

40.Differntial coil system can be of which of the following types? (See figure 15)

a.Sketch no. 1

b.Sketch no. 2

c.Sketch no. 3

d.All of the above

e.Both a and b

EDDY CURRENT QB 1

ANSWERS

Q.NO ANSWERS Q.NO ANSWERS
1 B 21 C
2 A 22 D
3 D 23 B
4 A 24 C
5 C 25 A
6 D 26 A
7 B 27 E
8 B 28 B
9 C 29 D
10 B 30 E
11 B 31 A
12 B 32 A
13 B 33 B
14 C 34 A
15 D 35 B
16 B 36 B
17 D 37 C
18 B 38 A
19 D 39 E
20 B 40 D

API 580 RBI Risk Based Inspection | Basic Concepts

RBI Risk Based Inspection

 

Chapter 3

Basic Concepts

What is Risk?

  • Risk is something that we live with on a day-to-day basis
  • What is a Risk Decision?
  • Examples from every day life

An Example of a Risky Decision

api training

 

Acceptance of Risk

  • We accept risk because the probability of a serious catastrophe is sufficiently low to make it acceptable

Risk

  • Risk is the combination of the probability of an event occurring during some time period and the consequence (generally negative) associated with the event

Risk = Probability x Consequence

Perception of Risk Versus Reality

Management      Perception

Engineers

Supervisors

Operators

Craftsman         Reality

A Perception of a Risky Decision

api trainingRisky Decision Event Tree

api trainingRisk Management and Risk Reduction

  • Not really synonymous
  • Risk reduction is a part of risk management
  1. Act of mitigating a known risk to a lower level
  • Risk Management is a process
  1. To assess risk
  2. To determine if risk reduction is required
  3. To develop a plan to maintain risks at an acceptable level
  4. Some risks may be identified as acceptable
  5. Some risks may be inherent

Management of Risk Using RBI

api trainingEvolution of Inspection Intervals

  • Inspection programs are established to detect and evaluate deterioration due to in-service operations
  • Periodic verification of equipment integrity evolved as “calendar-based” intervals
  • Effectiveness varied widely

Evolution of Inspection Approach

  • Better understanding of type and rate of deterioration
  • Intervals became more dependent on equipment condition
  • Codes and standards evolved
  1. Percentage of equipment life interval
  2. On-stream in lieu of internal inspection
  3. Process environment induced cracking
  4. Consequence based inspection intervals

Traditional Equipment Inspection

api trainingRBI – The Next Generation

  • Ultimate Goal of Inspection
  1. Safety and Reliability of Operating Facilities
  • RBI Approach
  1. Focuses attention specifically on equipment and associated deterioration mechanisms representing the most risk to the facility

Inspection Optimization

  • Optimization for planning and implementing a risk based inspection program needs information on:
  1. Risk associated with equipment
  2. Relative effectiveness of inspection techniques to reduce risk
  • Not all inspection programs are equally effective in detecting in-service deterioration and reducing risks
  • Various inspection techniques are usually available to detect any given deterioration mechanism
  • Each method will have a different effectiveness.

Relative Risk vs. Absolute Risk

  • Complexity of risk calculation is function of factors affecting risk
  1. Absolute risk is virtually impossible to determine because of too many uncertainties
  • RBI is focused on a systematic determination of relative risk
  • Risk acceptance may be evaluated by sensitivity analysis

RISK BASED INSPECTION RBI | API TRAINING IN TRICHY

RISK BASED INSPECTION RBI

CHAPTER II

Definitions and Acronyms in RISK BASED INSPECTION

Consequence

  • Consequence: Outcome from an event. There may be one or more consequences from an event. Consequences may range from positive to negative. However, consequences are always negative for safety aspects. Consequences may be expressed qualitatively or quantitatively.

Damage Tolerance and Deterioration

  • Damage Tolerance: The amount of deterioration that a component can withstand without failing.
  • Deterioration: The reduction in the ability of a component to provide its intended purpose of containment of fluids. This is caused by various deterioration mechanisms (e.g. thinning, cracking, mechanical). Damage or degradation may be used in place of deterioration.

Event and Event Tree in risk based inspection

  • Event: Occurrence of a particular set of circumstances. The event may be certain or uncertain. The event may be singular or multiple. The probability associated with the event is estimated for a given period of time.
  • Event Tree: A tool that organizes potential accidents in a logical manner. The event tree begins with identification of potential initiating events. Subsequent possible resulting events are then displayed as the second level of the event tree. This process is continued to develop pathways or scenarios from the initiating events to potential outcomes.

External Event

  • External Event: External events are usually beyond the direct or indirect control of persons employed at or by the facility. Events resulting from forces of nature, acts of Allah or sabotage, or neighboring events fires or explosions, hazardous releases, electrical power failures, climatic catastrophes, earthquakes, and intrusions.

Failure and Failure Mode

  • Failure: Termination of the ability of a system, structure, or component to perform its required function of containment of fluid (i.e. loss of containment). Failures may be unannounced and undetected until the next inspection (unannounced failure), or they may be announced and detected by any number of methods at the instance of occurrence (announced failure).
  • Failure Mode: The manner of failure. For Risk Based Inspection, the failure of concern is loss of containment of pressurized equipment items. Examples of failure modes are small hole, crack, and rupture.

Source and Hazard in risk based inspection

  • Source: Thing or activity with a potential for consequence. Source in a safety context is a hazard.
  • Hazard: A physical condition or a release of a hazardous material that could result from component failure and result in human injury or death, loss or damage, or environmental degradation. Hazard is the source of harm. Components that are used to transport, store, or process a hazardous material are a source of hazard. Human error and external events can also create a hazard.

Hazard and Operability Study

  • Hazard and Operability (HAZOP) Study: A form of failure modes and effects analysis, which uses systematic techniques to identify hazards and operability issues.
  • Identifying unforeseen design, process, or operational hazards.
  • The basic objectives are:
  1. To produce a full description of the facility or process, including the intended design conditions.
  2. To systematically review every part to discover how deviations from the intention of the design can occur.
  3. To decide whether deviations can lead to hazards or operability issues.
  4. To assess effectiveness of safeguards.

Likelihood and Probability

  • Likelihood: Probability.
  • Probability: Extent to which an event is likely to occur within a time frame. Probability is “a real number from 0 to 1 attached to a random event”. Probability is related to long-run relative frequency or degree of belief in an occurrence. Frequency rather than probability is used. Degrees of belief is chosen as classes or ranks.
  1. “Rare/unlikely/moderate/likely/almost certain” or “incredible/improbable/remote/ occasional/probable/frequent”.

Qualitative Risk Analysis in risk based inspection

  • Qualitative Risk Analysis (Assessment): Method that uses engineering judgment and experience as the basis for analysis of probabilities and consequences of failure.
  1. Results of qualitative risk analyses are dependent on the background and expertise of the analysts and the objectives of the analysis.
  2. Failure Modes, Effects, and Criticality Analysis (FMECA) and HAZOPs are examples of qualitative risk analysis techniques that become quantitative risk analysis methods when consequence and failure probability values are estimated along with the respective descriptive input.
  3. Identifies and delineates the combinations of events that, if they occur, will lead to a severe accident (e.g. major explosion) or any other undesired event.
  4. Estimates the frequency of occurrence for each combination.
  5. Estimates the consequences.
  • Quantitative risk analysis integrates into a uniform methodology the relevant information about design, operating practices and history, reliability, human actions, physical progression of accidents, and potential health and environmental effects, as realistically as possible.

Risk
Relative, Absolute, and Residual

  • Risk: Combination of probability of an event and its consequence. In some cases, risk is a deviation from the expected. When probability and consequence are expressed numerically, risk is the product.
  • Relative Risk: The comparative risk of a facility, process unit, system, or equipment to other facilities, process units, systems, or equipment, respectively.
  • Absolute Risk: An ideal description of quantification risk.
  • Residual Risk: The risk remaining after mitigation.

Risk
Analysis, Assessment, and Acceptance

  • Risk Analysis: Systematic use of information to identify sources and to estimate the risk
  1. Risk analysis provides a basis for risk evaluation and risk acceptance. Information can include historical data, analysis, informed opinions and concerns of stakeholders.
  • Risk Assessment: Overall process of risk analysis and risk evaluation.
  • Risk Acceptance: A decision to accept a risk. Risk acceptance depends on risk criteria.

Risk
Criteria and Identification

  • Risk Criteria: Terms of reference by which the significance of risk is assessed. Risk criteria may include associated cost and benefits, legal and statutory requirements, socio-economic and environmental aspects, concerns of stakeholders, priorities and other inputs to the assessment.
  • Risk Identification: Process to find, list, and characterize elements of risk. Elements may include; source, event, consequence, probability. Risk identification may also identify stakeholder concerns.

Risk
Estimation and Evaluation

  • Risk Estimation: Process used to assign values to the probability and consequence of a risk. Risk estimation may consider cost, benefits, stakeholder concerns and other variables, as appropriate for risk evaluation.
  • Risk Evaluation: Process used to compare the estimated risk against given risk criteria to determine the significance of the risk. Risk evaluation may be used to assist in the acceptance or treatment decision.

Mitigation

  • Mitigation: Limitation of any negative consequence or reduction in probability of a particular event.

 

 

 

RBI Risk Based Inspection | API TRAINING IN TRICHY

RBI RISK BASED INSPECTION

Chapter I

What is RBI Risk Based Inspection?

  • Strategic, systematic process for identifying risk and managing risk and its associated costs
  • Integrated, data-based methodology that factors risk into inspection decision making
  • Includes likelihood of failure (LOF) and consequence of failure (COF)
  • Includes both qualitative and quantitative analysis
  • Prioritizes relative and/or absolute risk
  • Identifies areas requiring risk mitigation

Approaches to RBI  Risk Based Inspection

  • There are many different types of RBI analysis

Proposed API Recommended Practice 580

  • Status – Currently in final balloting stage
  • Focus of this Course

ASME Inspection Planning Standard

  • Major focus is on nuclear and fossil power generation

Integration of API Practices

  • API RP 580, Risk Based Inspection is integrated with other practices
  •  API Code 510, Pressure Vessels
  • API Code 570, Piping
  • API Standard 653, Storage Tanks
  • API RP 579 Fitness-for-Service
  • API RP 750 Management of Process Hazards
  • API RP 571–577, Inspection of Equipment Types
  • API RP 578, Positive Materials Identification
  • Proprietary commercial methods
  • Owner-User methods

Purpose of RBI Risk Based Inspection

  • Risk Based Inspection is a methodology of basic elements which is expected to provide a linkage of risks with appropriate inspection or other risk mitigations activities to manage the risks.

Scope of RBI Risk Based Inspection

  • The risk management principles and concepts that RBI is built on are universally applicable
  • RBI, as will be discussed, is targeted for the hydrocarbon industry
  1. Petroleum
  2. Gas
  3. Chemicals
  4. Petrochemicals                                                                                                                                                                                                                                RBI principles will work in any industry exposed to risk

 

  • Other Aspects of Scope
  1. Flexibility in Application
  2. Mechanical Integrity Focus
  3. Equipment Covered & Not Covered

Flexibility in Application of RBI Risk Based Inspection

  • Flexibility addresses:
  1. Diversity of Organizational Size and Culture
  2. Regulatory Requirements
  3. Corporate Risk Management Practices
  4. Unique Local Circumstances
  • Other Aspects
  1. Attributes of a Quality Risk Assessment Program
  2. Imposition of Undue Constraints on Users
  3. Provides Consistency

Mechanical Integrity Focus of RBI Risk Based Inspection

  • RBI process is focused on maintaining the mechanical integrity of pressure equipment and minimize risk of loss of containment
  • RBI Complements
  1. Fitness-for-Service of RBI Risk Based Inspection
  • Management of acceptable risk and mitigation of risk
  1. Process Hazard Analysis
  • Inspection relates to deterioration mechanisms
  1. Reliability Centered Maintenance
  • Both focus on understanding failure modes

Scope of Equipment in RBI Risk Based Inspection

  • Covered Equipment
  1. Pressure Vessels
  2. Process Piping
  3. Heat Exchangers
  4. Heaters and Boilers
  5. Storage Tanks
  6. Rotating Equipment
  • Pressure boundary
  1. Pressure Relief Devices
  • Excluded Equipment
  1. Instrumentation
  2. Control Systems
  3. Electrical Systems
  4. Structural Systems
  5. Machinery Components

Implementation by API

  • API Code 510, Pressure Vessels
  • API Code 570, Piping
  • API Standard 653, Storage Tanks
  • API RP 579 Fitness-for-Service
  • API RP 750 Management of Process Hazards
  • API RP 571–577, Inspection of Equipment Types
  • API RP 578, Positive Materials Identification
  • API Publ. 581, API RBI Methodology/Software

API RP 580 RBI Risk Based Inspection and Publ. 581 Differences

  • API RP 580 RBI Risk Based Inspection
  1. Outlines conceptual approaches and necessary elements to be included in a quality RBI effort
  2. Inclusive of several approaches to RBI available for numerous sources
  • API Publication 581
  1. Outlines the specific RBI methodology developed by the API RBI sponsor group
  2. It is one step-by-step approach to RBI that contains all the necessary elements to satisfy RP 580

Comparison of API and ASME Risk Based Inspection Practices

  • No philosophical differences
  • Differences in documents
  1. Differences in scope and goals
  • ASME project aims at developing guidelines for inspection
  • API project intended to develop usable tools and methodologies for the plant level
  • API project builds on ASME methods but with appropriate simplification

Process Hazard Analysis (PHA) Linkage

  • PHA + RBI =Total Process and Mechanical Integrity Hazards Analysis Associated with Operating Plants

Reliability Centered Maintenance (RCM) Linkage

  • RCM + RBI =Total Reliability and Pressure Integrity Analysis for Functional Breakdown and Leak/Rupture

 

RADIOGRAPHY | NDT Training in Trichy | ESL

 

RADIOGRAPHY OR  RADIOGRAPHIC TESTING

radiography radiographyIntroduction

  • This module presents information on the NDT method of radiographic inspection or radiography.
  • Radiography uses penetrating radiation that is directed towards a component.
  • The component stops some of the radiation. The amount that is stopped or absorbed is affected by material density and thickness differences.
  • These differences in “absorption” can be recorded on film, or electronically.

Outline

  • Electromagnetic Radiation
  • General Principles of Radiography
  • Sources of Radiation

–Gamma Radiography

–X-ray Radiography

  • Imaging Modalities
  • Advantages and Limitations
  • Glossary of Terms

Electromagnetic Radiation

The radiation used in Radiography testing is a higher energy (shorter wavelength) version of the electromagnetic waves that we see every day. Visible light is in the same family as x-rays and gamma rays.

radiographyGeneral Principles of Radiography

The part is placed between the radiation source and a piece of film. The part will stop some of the radiation. Thicker and more dense area will stop more of the radiation.

The film darkness (density) will vary with the amount of radiation reaching the film through the test object. radiographyThe energy of the radiation affects its penetrating power. Higher energy radiation can penetrate thicker and more dense materials.

The radiation energy and/or exposure time must be controlled to properly image the region of interest.

radiographyFlaw Orientation

Radiography has sensitivity limitations when detecting cracks.

X-rays “see” a crack as a thickness variation and the larger the variation, the easier the crack is to detect.

When the path of the x-rays is not parallel to a crack, the thickness variation is less and the crack may not be visible.

radiography

Since the angle between the radiation beam and a crack or other linear defect is so critical, the orientation of defect must be well known if radiography is going to be used to perform the inspection.

radiographyRadiation Sources

Two of the most commonly used sources of radiation in industrial radiography are x-ray generators and gamma ray sources. Industrial radiography is often subdivided into “X-ray Radiography” or “Gamma Radiography”, depending on the source of radiation used.

radiographyGamma Radiography

  • Gamma rays are produced by a radioisotope.
  • A radioisotope has an unstable nuclei that does not have enough binding energy to hold the nucleus together.
  • The spontaneous breakdown of an atomic nucleus resulting in the release of energy and matter is known as radioactive decay.

radiographyMost of the radioactive material used in industrial radiography is artificially produced.

This is done by subjecting stable material to a source of neutrons in a special nuclear reactor.This process is called activation.

radiographyUnlike X-rays, which are produced by a machine, gamma rays cannot be turned off. Radioisotopes used for gamma radiography are encapsulated to prevent leakage of the material.The radioactive “capsule” is attached to a cable to form what is often called a “pigtail.”

radiographyX-ray Radiography

Unlike gamma rays, x-rays are produced by an X-ray generator system. These systems typically include an X-ray tube head, a high voltage generator, and a control console.

radiography radiographyX-rays are produced by establishing a very high voltage between two electrodes, called the anode and cathode.

To prevent arcing, the anode and cathode are located inside a vacuum tube, which is protected by a metal housing

Imaging Modules:

Several different imaging methods are available to display the final image in industrial radiography:

  • Film Radiography
  • Real Time Radiography
  • Computed Tomography (CT)
  • Digital Radiography (DR)
  • Computed Radiography (CR)

Advantages of Radiography

  • Technique is not limited by material type or density.
  • Can inspect assembled components.
  • Minimum surface preparation required.
  • Sensitive to changes in thickness, corrosion, voids, cracks, and material density changes.
  • Detects both surface and subsurface defects.
  • Provides a permanent record of the inspection.

Disadvantages of Radiography

  • Many safety precautions for the use of high intensity radiation.
  • Many hours of technician training prior to use.
  • Access to both sides of sample required.
  • Orientation of equipment and flaw can be critical.
  • Determining flaw depth is impossible without additional angled exposures.
  • Expensive initial equipment cost.

Glossary of Terms

  • Activation: the process of creating radioactive material from stable material usually by bombarding a stable material with a large number of free neutrons. This process typically takes place in a special nuclear reactor.
  • Anode: a positively charged electrode.
  • Automatic Film Processor: a machine designed to develop film with very little human intervention. Automatic processors are very fast compared to manual development
  • Capacitor: an electrical device that stores an electrical charge which can be released on demand
  • Cathode: a negatively charged electrode.
  • Darkroom: a darkened room for the purpose of film development. Film is very sensitive to exposure by visible light and may be ruined.
  • Exposure: the process of radiation penetrating and object.
  • Gamma Rays: electromagnetic radiation emitted from the nucleus of a some radioactive materials

 

To Learn Radiography or Radiographic Testing : Contact Ph: +91 – 85261 41878 Email ID: esl@esltraining.in.

PENETRANT TESTING | NDT Training In Trichy | ESL

 

PENETRANT TESTING

Penetrant TestingIntroduction

  • This module is intended to provide an introduction to the NDT method of penetrant testing.
  • Penetrant Testing, or PT, is a nondestructive  testing method that builds on the principle  of Visual Inspection.
  • PT increases the “seeability” of small discontinuities that the human eye might not be able to detect alone.

Penetrant TestingOutline:

  • General Introduction
  • Penetrant Materials and Considerations
  • Basic Steps in Penetrant Testing
  • Common Equipment
  • Advantages and Limitations
  • Summary
  • Glossary of Terms

How Does PT Penetrant Testing Work?

  • In penetrant testing, a liquid with high surface wetting characteristics is applied to the surface of a component under test.
  • The penetrant “penetrates” into surface breaking discontinuities via capillary action and other mechanisms.
  • Excess penetrant is removed from the surface and a developer is applied to pull trapped penetrant back the surface.
  • With good inspection technique, visual indications of any discontinuities present become apparent.

Penetrant Testing

What Makes PT Penetrant Testing Work?

  • Every step of the penetrant process is done to promote capillary action.
  • This is the phenomenon of a liquid rising or climbing when confined to small openings due to surface wetting properties of the liquid.
  • Some examples:

–Plants and trees draw water up from the ground to their branches and leaves to supply their nourishment.

–The human body has miles of capillaries that carry life sustaining blood to our entire body.

Penetrant Testing

Basic Process of PT Penetrant Testing

1) Clean & Dry Component

2) Apply Penetrant

Penetrant Testing

3) Remove Excess

Penetrant Testing

4) Apply Developer

Penetrant Testing

5) Visual Inspection

Penetrant Testing

6) Post Clean Component

What Can Be Inspected Via PT Penetrant Testing?

Almost any material that has a relatively smooth, non-porous surface on which discontinuities or defects are suspected.

Penetrant TestingWhat Can NOT be Inspected Via PT Penetrant Testing?

  • Components with rough surfaces, such as sand castings, that trap and hold penetrant.
  • Porous ceramics
  • Wood and other fibrous materials.
  • Plastic parts that absorb or react with the penetrant materials.
  • Components with coatings that prevent penetrants from entering defects.Penetrant TestingDefect indications become less distinguishable as the background “noise” level increases.

What Types of Discontinuities       Can Be Detected Via PT Penetrant Testing?

All defects that are open to the surface.

–Rolled products– cracks, seams, laminations.

–Castings–cold shuts, hot tears, porosity, blow holes, shrinkage.

–Forgings– cracks, laps, external bursts.

–Welds– cracks, porosity, undercut, overlap, lack of fusion, lack of penetration.

Penetrant Testing Choices of Penetrant Materials

Penetrant :

Type

I   Fluorescent

II Visible

Method     

A Water Washable

B Postemulsifiable – Lipophilic

C Solvent Removable

D Postemulsifiable – Hydrophilic

Developer:          

Form

Dry Powder

Wet, Water Soluble

Wet, Water Suspendable

Wet, Non-Aqueous

6 Steps of Penetrant Testing

  1. Pre-Clean
  2. Penetrant Application
  3. Excess Penetrant Removal
  4. Developer Application
  5. Inspect/Evaluate
  6.  Post-clean

Advantages of Penetrant Testing

  • Relative ease of use.
  • Can be used on a wide range of material types.
  • Large areas or large volumes of parts/materials can be inspected rapidly and at low cost.
  • Parts with complex geometries are routinely inspected.
  • Indications are produced directly on surface of the part providing a visual image of the discontinuity.
  • Initial equipment investment is low.
  • Aerosol spray cans can make equipment very portable.

Limitations of Penetrant Testing

  • Only detects surface breaking defects.
  • Requires relatively smooth nonporous material.
  • Precleaning is critical. Contaminants can mask defects.
  • Requires multiple operations under controlled conditions.
  • Chemical handling precautions necessary (toxicity, fire, waste).
  • Metal smearing from machining, grinding and other operations inhibits detection. Materials may need to be etched prior to inspection.
  • Post cleaning is necessary to remove chemicals.