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Title: AUDITOR%20NDT%20TRAINING


1
AUDITOR NDT TRAINING
  • The purpose of this training is to give the
    auditor a familiarity of the quality control and
    quality assurance systems associated with
    Nondestructive testing.

2
Introduction
  • The reference material used in this presentation
    is SNT-TC-1A, ASTM Standards 2000 edition,
    Nondestructive inspection evaluation checklist
    (from FAA sight).
  • From this presentation you should be able to be
    able to understand and evaluate an NDT facilities
    quality systems.

3
Agenda
  • Training and Certification.
  • Audit/Evaluation Surveillance.
  • Liquid Penetrant Inspection.
  • Magnetic Particle Inspection.
  • Radiography Inspection.
  • Ultrasonic Inspection.
  • Eddy Current Inspection.

4
Overview
  • It is recognized that the effectiveness of
    nondestructive testing applications depends upon
    the capabilities of the personnel who are
    responsible for and perform it.
  • As the auditor you will be required to evaluate
    NDT personnel and facilities to make a
    determination of compliance in accordance with
    the vendors manual, and required specifications.
  • The five elements that can be used to evaluate
    any NDT organization from manufacturing to
    maintenance.

5
Overview
  • 1) Documentation- written procedures,
    processes specifications and/or methods used by
    the vendor in performance and controls of NDT
    activities.
  • 2) Organization- relationship of NDT
    organization to management.
  • 3) Environment- the general physical
    condition of the facility, e.g.,housekeeping,
    storage, safety, consumable management,
    equipment.
  • 4) Calibration- process by which an item is
    checked to a standard.
  • 5) Training- methods used and records
    maintained to train and retrain NDT personnel

6
Training and Certification
  • The requirements for training, qualification, and
    certification in each NDT method should be part
    of the vendors manual or written practice.
  • Some recommended practices are ASN-TC-1A,
    ANSI/ASNTCP89 NAS 410 (previously Mil Std 410E),
    ATA105, ISO 9712.

7
Training and certification
  • Three basic Levels of qualification.
  • 1) Level I- An NDT Level I individual should
    be qualified to properly perform specific
    calibrations, specific NDT, and specific
    evaluations for acceptance or rejection
    determinations according to written instructions
    and to record results.The NDT Level I should
    receive the necessary instruction or supervision
    from a certified Level II or III individual.

8
Training and certification
  • 2) Level II- An NDT Level II individual should
    be qualified to set up and calibrate equipment
    and to interpret and evaluate results with
    respect to applicable codes, standards and
    specifications.The Level II should be thoroughly
    familiar with the scope and limitations for
    methods for which qualified and should exercise
    assigned responsibilities for OJT training and
    guidance of trainees and Level I personnel.

9
Training and certification
  • 3) Level III- An NDT Level III individual
    should be capable of developing, qualifying, and
    approving procedures, establishing and approving
    techniques, interpreting codes, standards, and
    specifications and procedures and designating
    the particular NDT methods, techniques, and
    procedures used. The NDT Level III should be
    responsible for the NDT operations for which
    qualified and assigned and should be capable of
    interpreting and evaluating results in terms of
    existing codes, standards and specifications.

10
Training and certification
  • Level III continued- The NDT Level III should
    have sufficient practical background in
    applicable materials, fabrication and product
    technology to establish techniques and to assist
    in establishing acceptance criteria when none are
    otherwise available. The NDT Level III should
    have general familiarity with other appropriate
    NDT methods, as demonstrated by an ASNT Level III
    examination or other means. The NDT Level III ,
    in the methods in which certified, should be
    capable of training and examining NDT Level I and
    II personnel for certification in those methods

11
Training and certification
  • Some procedure also may call out for a trainee, a
    trainee is not authorized to accomplish,
    interpret or report any inspection requirements.
  • Some procedures may also call out for an NDT
    instructor an instructor is usually a Level II
    working under direction of the companies Level
    III.
  • These Levels may also be subdivided into approval
    to comply with specific procedures such as
    conductivity, ultrasonic thickness measurement(
    should be in the vendors written practice)

12
Training and certification
  • The required amount of training required to
    qualify and certify the NDT inspector should be
    part of the vendors written practice.
  • The requirements of each recommended practice
    vary on the amount of formal training and
    experience.
  • Personnel should complete sufficient organized
    training to become thoroughly familiar with
    principles and practices of the specified NDT
    method.

13
Examination
  • May be accomplished by an outside agency, but
    does not alleviate the employer of
    responsibility.
  • For Level I and II a general, specific, and
    practical test is required.(ASNT)
  • For Level III a basic, method, and specific test
    is required.(ASNT)

14
Examination
  • The Level III shall be responsible for the
    administration and grading of examinations for
    Level I Level II or other Level III personnel.
  • For Level I or II personnel the composite grade
    should be determined by averaging the results of
    the general, specific and practical exam.(ASNT)
  • Note-ISO 9712 has a general and specific exam and
    each exam will have a written and a practical
    part
  • For Level III personnel the composite grade
    should be determined by averaging the results of
    the basic (required only once), method, and
    specific exams.(ASNT)

15
Examination
  • Minimum passing grade should consist of no
    individual test grade below 70 and the composite
    grade should be no less than 80 (ASNT).
  • When an examination is administered and graded
    for an employer by an outside agency and the
    outside agency issues a pass or fail only, on a
    certified report the employer may accept the pass
    grade as a 80 for that particular examination
    (ASNT).

16
Examination
  • Also an eye exam should be accomplished
    annually for near vision acuity and every 3 years
    for color contrast Differentiation.
  • Re-certification for Level I and II should be
    every 3years, Level III every 5 years.(ASNT)

17
Training and certification
  • The employers certification shall be deemed
    revoked when employment is terminated.
  • A Level I, II or III certification may be
    re-instated to the former NDT Level by a new
    employer based on examination, provided all the
    all these conditions have been met.
  • 1) employee has proof of prior certification.
  • 2) The employee was working in the capacity
    to which certified within 6 months of
    termination.
  • 3)The employee is being re-certified within
    within 6 months of termination.

18
Training and certification
  • 4) Prior to being examined for certification,
    employees not meeting the above requirements
    should receive additional training as deemed
    appropriate by the Level III.(ASNT)

19
Training and certification
  • A Level I, II, or III whose certification has
    been terminated may be re-instated to the former
    NDT Level, without a new examination, provided
    all the following conditions have been met.
  • 1) The employer has maintained the
    personnel certification records.
  • 2) The employees certification did not
    expire during termination.
  • 3) The employee is being re-instated within
    6 months of termination (ASNT)

20
Audit / Evaluation and Surveillance
  • Documentation
  • 1) Does the facility have a manual to
    include an organizational chart?
  • 2) Does the manual contain or refer to the
    appropriate specifications, are they current ,
    and available?
  • 3) Are there provisions in the manual for
    internal review/evaluation and are the
    appropriate records maintained?

21
Audit / Evaluation and Surveillance
  • 5) Are there procedures in place to revise the
    manual?
  • 6) Are there procedures in place for retention of
    records?
  • 7) Does the manual contain procedures that
    address nonconformities?
  • 8) Are the manuals and procedures available to
    and used by qualified personnel?
  • 9) Does the manual contain controls for
    subcontracts for NDI services?
  • 10) Does the manual contain controls for
    management of NDI products, materials, and
    consumables?

22
Audit/Evaluation and Surveillance
  • 11) Is there a separate NDI organization in the
    facility?
  • 12) Does the NDI manager or equivalent have
    direct line authority to the NDI qualified
    personnel?
  • 13) Are the NDI requirements provided to the NDI
    inspection personnel by use of written practice?
  • 14) Does the NDI manager, or equivalent, review
    the quality assurance system to monitor
    compliance to the FAA approved data?
  • 15) Are proper shift change procedures in place?

23
Audit/Evaluation and Surveillance
  • Environment
  • 1) Is the size of the work area sufficient to
    perform the NDI inspections?
  • 2) Is there adequate work area for storage and
    separation of NDI materials?
  • 3) Is there a method for controlling and
    segregating nonconforming NDI equipment and
    materials?
  • 4) Are appropriate manuals, procedures, and other
    documentation available for use by qualified
    personnel?

24
Audit/Evaluation and Surveillance
  • Environment (continued)
  • 5) Are adequate parts handling systems (cranes,
    hoists, lifts etc) available?
  • 6) Do routing documents specify the operation
    needed and in what sequence?
  • 7) Is adequate protection provided to parts
    during handling and routing?
  • 8) Is metal to metal contact of finished surfaces
    prevented during handling?
  • 9) Are obsolete documents removed from inspection
    areas

25
Audit / Evaluation and Surveillance
  • Calibration
  • 1) Is there a procedure for calibrating
    inspection devices to certified standards?
  • 2) Are there procedures for segregation of
    functional and nonfunctional equipment?
  • 3) Are procedures in place to ensure
    repaired equipment is recalibrated?
  • 4) Are reference standards properly
    labeled, stored and used?
  • 5) Are independent data available for
    reference standards, ie., drawings, metrology,
    etc.?

26
Audit / Evaluation and Surveillance
  • Calibration (continued)
  • 6) Are the calibration methods documented?
  • 7) Do calibration methods include environment
    controls, standards to be used, and accuracy
    requirements?
  • 8) Are setup verifications performed on all
    shifts as appropriate?

27
Liquid Penetrant (ASTM E1417)
  • 2 Basic Types
    1) Type I
    Fluorescent 2) Type II
    Visible
  • 4 Methods 1) Method A Water washable 2)
    Method B Post-emulsified, lipophilic 3) Method
    C Solvent-removable 4) Method D
    Post-emulsified, hydrophilic

28
Liquid Penetrant
  • Sensitivity Levels These levels are for Type I
    penetrants only. Type II penetrants have only a
    single sensitivity and is not represented by any
    level. 1) Sensitivity Level ½ - Very low 2)
    Sensitivity Level 1 Low 3) Sensitivity Level
    2 Medium 4) Sensitivity Level 3 High 5)
    Sensitivity Level 4 Ultrahigh

29
Liquid Penetrant
  • Developers shall be the following forms 1) Form
    a Dry powder 2) Form b Water-soluble 3)
    Form c Water-suspendable 4) Form d
    Nonaqueous for Type I fluorescent. 5) Form
    e Nonaqueous for Type II visible dye. 6)
    Form f Specific application

30
Liquid Penetrant
  • Solvent removers shall be of the following
    classes 1) Class 1- Halogenated 2)
    Class 2 Nonhalogenated 3) Class 3 Specific
    application

31
Liquid Penetrant
  • Quality control and system performance. 1)
    Penetrant contamination Accomplished daily to
    determine if any of the following conditions are
    evident precipitates, waxy deposits, white
    coloration, separation of constituents, surface
    scum, or any other evidence of contamination or
    breakdown.

32
Liquid Penetrant
  • Developer contamination ( Aqueous soluble and
    suspendable) accomplished daily. 1)
    Checked for fluorescence, as appropriate, and
    coverage by immersing an aluminum panel. Failure
    to uniformly wet the panel or any observed
    fluorescence is unsatisfactory and the developer
    shall be replaced.

33
Liquid Penetrant
  • Developer concentration Aqueous soluble and
    suspendable accomplished weekly.
    1) Checked with a hydrometer to supplier
    specification.
  • Developer condition (Dry) accomplished daily.
    1) Check to
    see that the developer is fluffy and not caked
    also check for fluorescent specks 10 or more
    specks or any caking is unsatisfactory

34
Liquid Penetrant
  • Water wash pressure checked each shift. 1)
    Should not exceed 40 psi, minimum distance 12
    inches from part. (need not be recorded)
  • Water Temp. Checked each shift 50 to 100
    degrees F. Note If immersion rinse is
    being used the water should be agitated.

35
Liquid Penetrant
  • Black Light intensity Checked daily. 1)
    Minimum 1000 micro watt/cm2 at 15 inches also
    check filter for damage.
  • Inspection area cleanliness Checked daily (Need
    not be recorded)
  • Water based penetrant water concentration
    Checked weekly. 1) Checked with a
    refractometer to MFG. Specifications.

36
Liquid Penetrant
  • Non-water based penetrant water content (Method
    A) Checked monthly. 1)Test method D95 or Karl
    Fischer method. 5 water content Max.
  • Emulsifier concentration (hydrophilic) Checked
    weekly. 1) Checked with a refractometer to
    MFG specifications.

37
Liquid Penetrant
  • Penetrant sensitivity Checked weekly. 1) A
    comparison with unused sample if the sensitivity
    drops below unused material is unsatisfactory.
  • Fluorescent brightness Checked
    quarterly. 1) Usually accomplished in a
    Lab. With a fluorometer or a photofluorometer
    must maintain 90 of original brightness.

38
Liquid Penetrant
  • Penetrant removability (Method A) Checked
    monthly. 1) Test shall by accomplished using
    normal wash parameters compare with unused
    material.
  • Emulsifier removability Checked
    monthly. 1) Compare with unused material
    on test piece or production part.

39
Liquid Penetrant
  • Emulsifier water content (lipophilic) Checked
    monthly. 1) Test method D95 or Karl Fischer
    method usually sent to a Lab.
  • Drying oven calibration Checked quarterly (may
    be reduced or extended when substantiated by
    performance)

40
Liquid Penetrant
  • Light meter calibration Checked semiannually
    (may be reduced or extended when
    substantiated) 1) Both black light and
    visible light meters IAW MIL-STD-45662 or
    ANSI/NCSL Z540-1

41
Liquid Penetrant
  • Preparing and Precleaning All coatings and
    other conditions such as paint, plating,
    corrosion, scale, smeared metal, welding flux,
    chemical residues or any other material that
    could prevent from entering discontinuities,
    suppress dye performance, or produce unacceptable
    background.

42
Magnetic Particle(ASTM E1444)
  • Magnetic particle inspections can be accomplished
    wet, dry, fluorescent, visible, utilizing AC or
    DC current induced magnetism in the circular,
    longitudinal direction, or multidirectional.
  • FAR part 145.49 you must have equipment for wet
    and dry magnetic techniques, residual and
    continuous methods and portable for inspections
    of welds both on or off the aircraft.

43
Magnetic Particle
  • Quality control and performance checks.
  • Light intensity. Check daily 1) Black Light
    minimum intensity 1000 micro watt/cm2 also check
    filter for damage. 2) Visible Light
    minimum 100fc or 1000 lx. 3) Ambient Light
    2fc maximum.

44
Magnetic Particle
  • System performance using a test piece or ring
    specimen. Check daily.
  • Wet particle concentration. Check each shift
    Shall be .1 to .4ml in a 100ml sample fluorescent
    particles. Shall be 1.2ml to 2.4ml for
    nonfluorescent particles.
  • Gauss meter (Teslameter) reading zero. Check each
    use.
  • Gauss meter (Teslameter) accuracy. 6 months.
  • Ammeter accuracy. Check 6 months usually
    accomplished with a shunt and a calibrated
    ammeter IAW MFG specifications -10.

45
Magnetic Particle
  • Quick break check. Check 6 months - can use an
    oscilloscope or other method recommended by the
    MFG.
  • Dead weight check. Check 6 months Yokes and
    permanent magnets (when allowed) 1) A.C.
    shall have a lifting force of at least 10lbs with
    a 2 to 4 inch spacing. 2) D.C. lifting force
    30lbs 2 to 4inch spacing, or 50lbs 4 to 6inch
    spacing.

46
Magnetic Particle
  • Wet particle contamination. Check each shift/
    weekly. 1) Examine the the liquid above the
    precipitate with a black light. fluorescence
    should be comparable to original solution. 2)
    Examine the graduated portion of the tube both
    visible light and black light for striations or
    bands, different in color or appearance this may
    indicate contamination 30 maximum.

47
Magnetic Particle
  • Water break test. Check daily Only on water
    based vehicle with a wetting agent. 1) Flood the
    part with conditioned water, and the appearance
    is noted after flooding is stopped. If film of
    suspension breaks, exposing bare surface,
    insufficient wetting agent is present or the part
    has not been cleaned properly.

48
Magnetic Particle
  • Preparation of parts. 1) Demagnetize the
    part before examination if prior operations have
    produced a residual magnetic field. 2)The
    surface of the part to be inspected shall be
    smooth, clean, dry, and free of oil, scale,
    machining marks, or other contaminants or
    condition that might interfere with the
    efficiency of the inspection.

49
Magnetic Particle
  • 3) No coating that may prevent detection of
    surface defects. Paint or chrome greater than
    .003 inch in thickness, and ferromagnetic coating
    such as electroplated nickel greater than .001
    inch

50
Radiography
  • Safety and exposure requirements are regulated by
    the NRC and State agencies.
  • Individual exposure should be maintained on
    record at the facility.
  • Industrial radiation license is issued by the
    state and also thru the NRC for the use of a
    radioactive isotopes.
  • CFR 10 Parts 19, 20, 21, 30, 34 and 70 apply to
    regulating and licensing for use of radioactive
    isotopes.

51
Radiography
  • CFR 10 Part 19 regulations establish the
    requirements for posting of notices, work
    instructions and reports by licensees to persons
    (employees) who participate in licensed
    activities and options available to employees in
    connection with NRC inspections of licensees.
    Part 19 establishes the right and
    responsibilities of individuals and the NRC on
    any matter within the commissions jurisdiction.

52
Radiography
  • CFR 10 Part 20 establishes standards for
    protection against radiation hazards arising out
    of activity under licenses issued by the NRC.
    Part 20 discusses the concept of ALARA, and
    standards for dose limits for all persons who
    receive, possess, use or transfer material
    licensed under the NRC.

53
Radiography
  • CFR 10 Part 21 establishes reporting procedures
    and requirements for any individual or
    responsible officer of a firm constructing,
    owning, operating or supplying components
    licensed or regulated by the NRC that fail to
    comply with or regulations relating to safety.
    Part 21 establishes time limits for reporting to
    the NRC when basic component defect or failure
    pose a substantial hazard.

54
Radiography
  • CFR 10 Part 30 prescribes rules applicable to all
    persons in the United States governing domestic
    licensing of byproduct material under the Atomic
    Energy Act of 1954, as amended, and Title II of
    the Energy Reorganization Act of 1974.

55
Radiography
  • CFR 10 Part 34 establishes requirements for the
    issuance of licenses for the use of sealed
    sources containing byproduct material and
    radiation requirements for persons using such
    sealed sources in radiography. Nothing in this
    part shall apply to uses of byproduct material
    for medical diagnosis or therapy.

56
Radiography
  • Part 34 cont. Includes requirements for operating
    and emergency procedures, for training of
    radiography personnel, equipment performance,
    record maintenance, securing and storing
    radiographic exposure devices and personal
    audits.
  • CFR 10 Part 70 requirements for packaging,
    preparation for shipment, and transportation of
    licensed material.

57
Radiography
  • Radiation detection devices. 1) Survey Meter
    Measures dose rate. Gas filled tubes are used in
    the 2 types of survey meters the ionization
    chamber survey meter and the Geiger-Muller
    (or G-M) survey meter. The Ion chamber
    survey meter is primarily used. Survey meters
    should be calibrated every 6 months (CFR 10 Part
    34)

58
Radiography
  • 2) Pocket Dosimeter The pocket dosimeter is
    basically an air- filled ion chamber.The pocket
    dosimeter uses a charger to apply an electric
    charge to zero the quartz fiber as the dosimeter
    is exposed to ionization radiation, the ions
    created will neutralize the charge on the fiber
    and wire causing the fiber to move toward the
    wire giving a reading of exposure in
    milliroentgen (mR). The pocket dosimeter should
    be calibrated every12 months.

59
Radiography
  • 3) Film Badge or TLD Must be sent out monthly
    to a certified Lab for reading, they will send
    back a report of individual exposure, which must
    become a part of the individual personal exposure
    record.
  • 4) Rate Alarm Set to 500 mrem/hr. calibrate
    every 12 months, may only be required for use
    with isotopes.

60
Radiography
  • ALARA Is an acronym for as low as reasonably
    achievable which means make every effort to
    maintain radiation exposures as far below the
    dose limits as is practical.
  • The radiation area shall maintained to a maximum
    of 2 millirems.

61
Radiography
  • Storage of materials 1) Film should be
    stored in a cool dry place on its end, the
    expiration date should be on the box. 2)
    Chemicals (starter, fixer, and developer) should
    be stored in an appropriate locker. Most of these
    chemicals have a 2 year life limit marked on the
    box.

62
Radiography
  • Radiation Safety Officer. 1) The RSO is the
    individual with the responsibility for overall
    radiation safety program and who meets the
    requirements. 2) The RSO shall ensure that
    radiation safety activities are being performed
    in accordance with approved procedures and
    regulatory requirements in the daily operation of
    the licensees program. 3) The RSO shall
    establish and oversee all operating, emergency,
    and ALARA procedure.

63
Radiography
  • RSO cont. 4) Overseeing and approving all
    phases of the training program for radiographic
    personnel. 5) Ensure that the required radiation
    surveys and leak tests are performed and
    documented in accordance with regulations. 6)
    Ensure that personal monitoring devices are
    calibrated and used properly. 7)Ensuring that
    operations are conducted safely and to assume
    control for instituting corrective
    actions.

64
Radiography
  • Radiographer should have had not only the
    required amount of radiography training, but
    should have also had training in radiation
    safety. If the individual is using radioactive
    isotopes must meet the requirements of CFR10 Part
    34.
  • Radiographer Assistant Should have training in
    radiation safety and if using an isotope must
    meet the requirements of CFR 10 Part 34.

65
Ultrasound
  • Ultrasonic testing is the process of applying
    ultrasonic sound (above 20,000Hz) to a specimen
    and determining its soundness, thickness or some
    physical property.
  • Ultrasonic pulse echo instrument generates high
    voltage electrical pulse of short duration. These
    pulses are applied to the transducer which
    converts them into mechanical vibrations that are
    applied to the material.

66
Ultrasound
  • Ultrasonic through transmission Requires 2
    transducers one for sending and the other for
    receiving. Short or continuous waves are
    transmitted into the material.The quality of the
    material being tested is measured in terms of
    energy lost by the sound beam as it travels
    through the material.

67
Ultrasound
  • Contact testing Where the transducer is coupled
    to the material through a thin layer of couplant.
  • Immersion testing Both the material and the
    transducer are immersed in a tank of couplant
    (usually water).
  • Couplant The primary purpose of a couplant is
    to provide a suitable path between the transducer
    and the test surface
  • NOTE Do not use glycerin as a couplant on
    aluminum may cause corrosion

68
Ultrasound
  • Longitudinal wave Have particle vibrations in a
    back and forth motion in the direction of
    propagation.
  • Shear waves Have particle vibrations
    perpendicular to the direction of wave motion.
    Shear waves will not travel through liquid or
    gas.
  • Surface waves Are elastic vibrations whose
    energy is confined to a narrow region just below
    the surface.

69
Ultrasound
  • Displaying ultrasonic indications Three basic
    types A-scan, B-scan, C-scan. A-scan is a time
    versus amplitude display which reveals a
    discontinuity using a pip on a CRT. The A scan is
    read from left to right. B-scan typically
    uses an oscilloscope type screen to display a
    cross sectional view of the material being tested.

70
Ultrasound
  • C-scan Is a Plan View presentation similar
    to an X-ray picture.The C-scan shows shape and
    location of the discontinuity but does not show
    depth.

71
Ultrasound
  • Calibration standards Such as the IIW block,
    Miniature calibration block, Area amplitude
    blocks, DSC blocks and Distance amplitude
    blocks.Calibration standards are used for
    adjustments for simple ultrasonic testing
    procedures and to check on the reproducibility of
    measurement.

72
Ultrasound
  • Reference standards Aid in calibrating the
    instrument and indicating whether the
    discontinuities expected will be detected by
    preselected sensitivity. The standards apart from
    facilitating initial adjustment of the
    instrument, also check on reproducibility of the
    measurement.
  • Reference standard material should be identical
    to the object being tested in chemical
    composition, heat treat, physical and mechanical
    characteristics.

73
Ultrasound
  • Facility being evaluated should have the
    appropriate standards, transducers, equipment,
    technical data.
  • To prepare a part for ultrasonic inspection the
    part should be free of loose paint, dirt, and
    scale.

74
Eddy Current
  • Eddy current testing is a non-destructive test
    technique based on inducing electrical currents
    in the material being inspected and observing the
    interaction between those currents and the
    material.
  • Eddy Current can be used for crack detection,
    conductivity measurement, nonconductive coating
    thickness, material loss due to corrosion
  • Indicating devices An important part of the
    eddy current test system is the part of the
    instrument that gives the technician of the
    change in impedance. As usual there are several
    different types of devices used.

75
Eddy Current
  • 1) Analog meter 2) Digital
    meter 3) Oscilloscope 4) Impedance
    plane 5) Strip chart recorders

76
Eddy Current
  • Eddy Current Coils and Probes Inspection coils
    can have a variety of forms and can be arranged
    in a variety of ways. The choices of the type of
    arrangement of the inspection coil depends on the
    test situation. 1) Single coil
    absolute 2) double coil absolute 3)
    Differential coil arrangement 4)
    Reflection coil arrangement

77
Eddy Current
  • The previous coil arrangements can be installed
    on a variety of probe configurations such as. 1)
    Surface probes 2) Holes probes 3)
    Encircling 4) Internal (bobbin)
  • Erroneous indications can come from nonspecific
    variations in the test object such as coating
    thickness changes, conductivity changes, even
    electrical interference.

78
Eddy Current
  • Reference standards should be of the same
    material chemical composition, heat treat,
    physical and mechanical properties as the part to
    be inspected.

79
Eddy Current
  • Conductivity measurements Conductivity
    measuring can be used to determine a materials
    temper if you know the alloy, it can be used to
    sort different alloys, it can also be used to
    determine heat damage on aluminum alloys.
    Conductivity measurement alone can not be used to
    identify different alloys due to the overlap of
    conductivity ranges.

80
Eddy Current
  • Conductivity cont. Accomplishing a conductivity
    measurement is achieved by using a conductivity
    instrument setting it up with known calibration
    standards of known value. A reading is given in
    IACS (International Annealed Copper Standard)
    These standards should be checked periodically
    for accuracy due some materials conductivity
    changes with age

81
Eddy Current
  • Conductivity cont. Another way is to make a
    conductivity curve with an impedance plane
    instrument utilizing the calibration standard.
  • Surface and subsurface defects can be discovered
    using eddy current by using different probe and
    coil configurations. As a rule the lower the
    frequency used the larger the depth of
    penetration.

82
Eddy Current
  • As with any other NDT method the facility must
    have the appropriate equipment, probes,
    standards, technical data and trained personnel
    to perform the work.

83
Summary
  • In this class we have covered training and
    certification, audit and evaluation and 5 of the
    most commonly used NDT methods in general terms.
  • Read the vendors written practice, and look at
    the specifications in which inspections are to be
    accomplished Ensure that they have the required
    materials to accomplish the work. While using the
    1A standard and a little familiarity with NDT a
    thorough audit will be accomplished.

84
Information
  • Additional information on the subject of NDT can
    be purchased from the ASNT at asnt.org
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