Special Print – Will Not Be Kept Up To Date

Specification No. P3TF48

GE Issue No. S3
Aviation Date October 25, 2011
Page 1 of 31
CAGE Code 07482

General Electric Company

Supersedes P3TF48-S2
Cincinnati, OH 45215

GE PROPRIETARY INFORMATION
The information contained in this document is GE proprietary information and
is disclosed in confidence. It is the property of GE and shall not be used,
disclosed to others or reproduced without the express written consent of GE,
including, but without limitation, it is not to be used in the creation,
manufacture, development, or derivation of any repairs, modifications, spare
parts, designs, or configuration changes or to obtain FAA or any other
government or regulatory approval to do so. If consent is given for
reproduction in whole or in part, this notice and the notice set forth on
each page of this document shall appear in any such reproduction in whole or
in part.
This technical data is considered ITAR and/or EAR controlled pursuant to 22
CFR Part 120/130 and 15 CFR Parts 730-774, respectively. Transfer of this
data by any means to a Non-US Person, whether in the United States or abroad,
without the proper U.S. Government authorization (e.g., License, exemption,
NLR) is strictly prohibited.

SPECIFICATION

MAGNETIC PARTICLE INSPECTION (MPI)

(Using The Wet Fluorescent Continuous Method)

1. SCOPE

1.1 Scope. This specification establishes minimum requirements for

magnetic particle inspection used for the detection of surface or slightly
subsurface discontinuities in ferromagnetic materials. The inspection
technique is limited to the wet fluorescent continuous method.

1.1.1 Classification. This specification contains the following

class(es). Unless otherwise specified, the requirements herein apply to all
classes.

CLASS A

PREPARED REVIEWED APPROVED

RG Baur ⌧ EVENDALE
APPROVED DISTRIBUTION
F Bartos 10A ⌧ LYNN
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*1.2 Definitions. For purposes of this specification, the definitions in

ASTM E 1316 Section A and Section G shall apply. Additionally, the following
definitions shall apply.

Ambient Visible Light - The visible light level measured at the specimen
surfaces with the blacklight on.

Certifying Agent - A representative of the Purchaser’s technical

organization who has been approved to provide certification of MPI
personnel, processes and equipment. (See 8.5).

Contracting Agency - A prime contractor, subcontractor or government

agency procuring magnetic particle inspection services.

Contract Documents - The procuring contract and all drawings,

specifications, standards and other information included with or referred
to by the procuring contract.

Prime contractor - The organization that has responsibility to the

Government for the total system. The prime contractor may be the
Government in the procurement of such items as spare parts, special
items, or basic materials

Purchaser - The procuring activity of GE Aviation that issued the

procurement document invoking this specification. When this
specification is invoked by a U.S. Government purchasing activity (or
such activity's designee) the Purchaser shall mean such activity or
designee as the case may be.

Supplier - Source, other than GE Aviation, who provides material, parts

or services for incorporation into GE Aviation products.

1.3 Regulated Materials. The requirements of P2TF1, CL-A, shall be

complied with. The material(s) shown below were referenced in this
specification and P2TF1, CL-A, as of the date of this specification issue.
This list below does not include all materials which are referenced in sub-
tier documents.

There are no referenced materials.

2. APPLICABLE DOCUMENTS

*2.1 Issue of Documents. The following documents form a part of this

specification to the extent specified herein. Unless otherwise indicated, the
latest issue shall apply.

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AEROSPACE MATERIAL SPECIFICATIONS

AMS 2641 Vehicle, Magnetic Particle Inspection, Petroleum

Base
AMS 3044 Magnetic Particles, Fluorescent, Wet Method, Dry
Powder
AMS 3045 Magnetic Particles, Fluorescent, Wet Method, Oil
Vehicle, Ready-To-Use
AMS 3046 Magnetic Particles, Fluorescent, Wet Method, Oil
Vehicle, Aerosol Packaged

AREOSPACE STANDARDS (SAE)

AS 5282 Tool Steel Ring For Magnetic Particle Inspection

AMERICAN SOCIETY FOR TESTING AND MATERIALS

ASTM D 96 Water and Sediment in Crude Oil by Centrifugal

Method
ASTM D 445 Kinematic Viscosity of Transparent and Opaque
Liquids (and the Calculation of Dynamic Viscosity)
ASTM E 1316 Standard Terminology for Nondestructive
Examinations

FEDERAL STANDARDS

FED-STD-313 Material Safety Data, Transportation Data and

Disposal Data for Hazardous Materials Furnished to
Government Activities
FED-STD-595 Colors Used in Government Procurement

NATIONAL AEROSPACE STANDARD

NAS 410 (NAS) Certification and Qualification of

Nondestructive Test Personnel

MILITARY SPECIFICATION AND STANDARDS (DODISS)

DOD-F 87935 Fluid, Magnetic Particle Inspection, Suspension

Medium.

GE AVIATION SPECIFICATIONS

P2TF1 Regulated Materials

P3TF41 Control of Nondestructive Test and Inspection
Standards
P3TF45 Types of Records to be Retained for NDE
(Nondestructive Evaluation)

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*2.2 Order of Precedence. In the event of a conflict between the text of

this document and the references cited herein, the text of this document
takes precedence. Nothing in this document, however, supersedes applicable
laws and regulations unless a specific exemption has been obtained.

3. GENERAL REQUIREMENTS

3.1 Principles of Magnetic Particle Inspection Method

3.1.1 Intended Use of Magnetic Particle Inspection. The magnetic

particle inspection methods shall be used to detect cracks, laps, seams,
inclusions, and other discontinuities at or near the surface of ferromagnetic
materials only. Magnetic particle inspection may be applied to raw material,
billets, finished and semi-finished materials, welds, and in-service parts.

3.1.2 Magnetization and Particle Application. Magnetic particle

inspection consists of magnetization of the area to be inspected, application
of suitably prepared magnetic particles while the area is magnetized or being
magnetized, and subsequent classification, interpretation, and evaluation of
any resulting particle accumulations. In order to detect discontinuities in
all directions at least two magnetic fields, perpendicular to one another in
a plane parallel to the surface being inspected shall be used, except when
specifically exempted by the Certifying Agent.

3.1.3 Classification, Interpretation and Evaluation. Magnetic particle

patterns produced during the inspection process shall be classified,
interpreted as to their cause, and then evaluated in terms of part integrity
according to requirements which define the type, size, location, orientation,
and area of concentration of discontinuities which are unacceptable in a
specific part. Metallographic evaluation shall be required if the above
cannot otherwise be determined.

3.2 Responsibility for Inspection. The supplier is responsible for

performance of all the inspections to the requirements specified herein. The
supplier shall specify more stringent requirements than the minimum specified
in this standard when necessary to assure that a component will meet its
function and reliability requirements. The supplier may utilize his own
inspection facilities or any other facilities when approved by the Purchaser.

*3.2.1 Alternative Inspection Procedures. Magnetic particle inspection

may be performed in accordance with an alternative procedure(s) to this
specification, if the procedure(s) is approved by the Purchaser (see 8.3).
Once established, an approved alternative inspection procedure shall not be
changed without prior written concurrence by the Purchaser.

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3.3 Qualification of Inspection Personnel. All personnel performing

magnetic particle inspection shall be qualified and certified in accordance
with NAS 410. Personnel making accept or reject decisions in accordance with
the process described by this specification shall be qualified to at least a
level II in accordance with NAS 410. Personnel performing the processing
steps described in this specification shall be qualified to at least level I
in accordance with NAS 410. Foreign procedures which are, at minimum, equal
to NAS 410 may be used with prior approval of the Purchaser.

3.4 Acceptance Requirements. The acceptance requirements applicable to

the part or group of parts shall be incorporated as part of a written
procedure either specifically or by reference to other applicable documents
containing the necessary information. Applicable drawings or other documents
shall specify the acceptable size and concentration of discontinuities for
the component, with zoning of unique areas as required by design
requirements. These acceptance requirements shall be as specified by
contract documents.

3.5 Written Procedure. Magnetic particle inspection shall be performed

in accordance with a written procedure applicable to the parts or group of
parts under test. The procedure shall be in accordance with the requirements
of this specification. The procedure shall be capable of detecting the
smallest rejectable discontinuity specified in the contract documents for the
part under test. The written procedure may be a general one if it clearly
applies to all the specified parts being tested and meets the requirements of
this specification. All written procedures shall be approved by an
individual qualified and certified to NAS 410, Level III for magnetic
particle inspection at the testing facility and shall be subject to approval
by the Purchaser.

3.5.1 Elements of the Written Procedure. The written procedure shall

include as a minimum the following elements, either directly or by reference
to the applicable documents:

(a) Identification of the parts to which the procedure applies. This

shall include the material and alloy of which the parts are
fabricated.
(b) Identification of the test parts used for system performance
verification (see 5.4.1 and 5.4.2).
(c) Areas of the part to be examined (include a sketch if necessary).
(d) Directions of magnetization to be used, the order in which they
are applied, and any demagnetization procedures to be used between
shots.
(e) Method of establishing the magnetization (stationary machine,
cable wrap, head shot, coil shot, etc.)
(f) Directions for positioning the part with respect to the
magnetizing equipment (include a sketch as necessary).
(g) The type of magnetizing current and the equipment to be used.
(h) The current level, or the number of ampere-turns, to be used and
the duration of its application.
(i) Part preparation required before testing.

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(j) The type of magnetic particle material to be used, the method and
equipment to be used for its application and the concentration
limits of the fluorescent particles.
(k) Type of records and method of marking parts after inspection.
(l) Acceptance requirements, to be used for evaluating indications and
disposition of parts after evaluation.
(m) Post inspection demagnetization and cleaning requirements.
(n) The procedure identification number and the date it was written.
(o) Sequence of the magnetic particle inspection as related to
manufacturing process operations.
(p) Requirement for a technique sheet to be prepared for each part
number and approved by the Level III.
(q) Identification of all special inspection equipment, such as
borescopes, mirrors, etc. and the features or areas where such
equipment is to be used during the inspection.

3.6 Record of Inspection. The results of all magnetic particle

inspections shall be recorded. All recorded results shall be identified,
filed, and made available to the Contracting Agency upon request. Records
shall provide for traceability to the specific part or lot inspected, and
shall identify the inspection contractor or facility and the procedures used
in the inspection. Record retention shall be in accordance with P3TF45.

3.7 Inspection Sequence

3.7.1 General Sequence. Magnetic particle inspection shall be performed

at a stage in fabrication or assembly that allows access to all areas of the
part required to be inspected and after the completion of operations that
could cause surface or near surface defects. These operations include, but
are not limited to, forging, heat treating, plating, passivation, cold
forming, welding, grinding, straightening, machining and proof loading.
Multiple magnetic particle inspections may be required at various levels of
fabrication or assembly to satisfy the inspection requirements.

*3.7.2 Sequence with Coatings. Magnetic particle inspection shall not be

performed with coatings in place that could prevent the detection of surface
defects in a ferromagnetic substrate. Such coatings include paint or chrome
plate greater than 0.003 inch (0.08 mm) in thickness or ferromagnetic
coatings such as electroplated nickel greater than 0.001 inch (0.03 mm) in
thickness. Parts that have tensile strength of 180 KSI (1241 MPa) or higher
that are heat treated and subsequently electroplated, shall also be inspected
after plating (unless otherwise specified in the contract documents).

3.7.3 Sequence with FPI. Fluorescent penetrant inspection shall always

precede magnetic particle inspection when both tests are required.

*3.8 Eye Glasses. When using fluorescent materials, inspectors shall not
wear eye glasses permanently tinted or equipped with light restrictive or
light sensitive lenses that darken when exposed to ultraviolet (UV) light or
sunlight. This is not intended to prohibit the use of eyeglasses with lenses
treated to absorb UV light.

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3.9 Dark Adaptation. Personnel shall wait at least one minute after
entering a darkened area for their eyes to adjust to the low level lighting
before performing magnetic particle inspection.

3.10 Equipment and Facilities

*3.10.1 Magnetizing and Demagnetizing Equipment. Performance of a

satisfactory magnetic particle inspection requires magnetization of the part
to a specified level in a specified direction in accordance with an approved
technique. Magnetization can be accomplished either by passing an electric
current directly through the material (direct method), by inducing a current
flow in the part under test (induced current method), or by placing the
material within the magnetic flux of an external source such as a coil
(indirect method). The type of magnetic particle equipment shall be either
stationary or special application units or both. Stationary machines shall
be equipped with an ammeter positioned for easy viewing by the inspector and
visible in darkened conditions used during inspection. Additionally, a
"hands free" method of energizing the equipment shall be provided, i.e., Bump
bar, foot switch, etc. The equipment used shall adequately fulfill the
magnetizing and demagnetizing current requirements, as specified herein,
without damage to the part under test and shall include the necessary
features required for safe operation.

3.10.2 Calibration/Certification of Equipment. As a minimum the

following equipment shall be calibrated or certified in accordance with
P3TF41.

(a) Indicators and controls used to control or verify processing

parameters such as current and voltage measuring devices, ammeter
shunts, timers, and gaussmeters.
(b) Light meters used to verify black light and white light intensity
requirements.
(c) Measuring devices and equipment used to determine the size of
magnetic particle indications by direct measurement for the
purpose of hardware acceptance.

*3.10.3 Viewing. Viewing areas shall be kept clean at all times. For
stationary fluorescent magnetic particle inspection, the ambient white light
background shall not exceed 2 foot-candles (20 lx/m2) when checked to the
requirements of 5.3. Black lights shall provide a minimum of 1200 micro
watts/cm2 when checked to the requirements 5.2. Viewing areas for portable
fluorescent magnetic particle inspection shall utilize dark canvas,
photographer's black cloth, or other methods to reduce the white light
background to 2 foot-candles (20 lx/m2) maximum when checked to the
requirements of 5.3 and black light intensity shall provide a minimum of 1200
microwatts/cm2 at the surface to be inspected.

3.10.4 Interpretation/Evaluation Devices. The necessary inspection

aides, such as mirrors and borescopes, magnification, and measuring devices
shall be provided to assist interpretation of indications.

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3.11 Materials

3.11.1 Magnetic Particle Materials. The particles used in magnetic

particle inspection shall be finely divided ferromagnetic materials which
have been treated to impart visibility against the background of the surfaces
under inspection. They shall be coated with a fluorescent material for use
with black light. The particles shall be designed for suspension at a given
concentration in a suitable liquid (wet method). The particles shall be
designed to have a high magnetic permeability and a low retentivity. Careful
control of particle size, shape, and material is required to obtain
consistent results. The particles shall be non-toxic, free from rust,
grease, paint, dirt or other deleterious material which might interfere with
their proper functioning.

*3.11.1.1 Wet Particle Requirements. Wet particles shall meet the

requirements of AMS 3044, AMS 3045 or AMS 3046, as applicable. In applying
these specifications, the particles shall show indications as listed in Table
I on the test ring specimen of Figure 1 using the following procedure:

Place a conductor with a diameter between 1 and 1.25 inches (25 and 31
mm) and a length greater than 16 inches (40 cm) through the center of the
ring. Center the ring on the length of the conductor. Circularly
magnetize the ring by passing the current specified in Table I through
the conductor. Apply the suspension to the ring using the continuous
method. Examine the ring within 1 minute after current application under
a black light with a minimum intensity of 1200 microwatts/cm2 at the
surface. Minimum number of hole indications shall meet or exceed those
specified in Table I.

*Table I – KETOS and AS 5282 Ring Specimens

Required Indications When Using the KETOS Ring Specimen of Figure 1

PARTICLES USED CENTRAL CONDUCTOR MINIMUM NUMBER

FWDC AMPERAGE OF HOLES INDICATED
WET SUSPENSION 1400 3
FLUORESCENT 2500 5
3400 6
Required Indications When Using the AS 5282 Ring Specimen of Figure 1

PARTICLES USED CENTRAL CONDUCTOR MINIMUM NUMBER

FWDC AMPERAGE OF HOLES INDICATED
WET SUSPENSION 500 3
FLUORESCENT 1000 5
1500 6
2500 7
3500 9

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3.11.1.2 Suspension Vehicles. The suspension vehicle for the wet method
shall be a light petroleum distillate conforming to AMS 2641 (Type I) or to
DOD-F-87935 or a suitable conditioned water that conforms to the requirements
of 3.11.1.4. When approved by the Purchaser, AMS 2641 (Type II) may be used.
The flash point and viscosity of the suspension shall be in accordance with
the requirements of AMS 2641 or DOD-F-87935. The background fluorescence of
the suspension vehicle shall be less than the limit specified in DOD-F-87935.

Hole 1 2 3 4 5 6 7 8 9 10 11 12

0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07
Diameter (0.18 (0.18 (0.18 (0.18 (0.18 (0.18 (0.18 (0.18 (0.18 (0.18 (0.18 (0.18
(1) cm) cm) cm) cm) cm) cm) cm) cm) cm) cm) cm) cm)
0.07 0.14 0.21 0.28 0.35 0.42 0.49 0.56 0.63 0.70 0.77 0.84
"D" (2) (0.18 (0.36 (0.53 (0.71 (0.90 (1.08 (1.26 (1.44 (1.62 (1.80 (1.98 (2.16
cm) cm) cm) cm) cm) cm) cm) cm) cm) cm) cm) cm)

(1) All hole diameters are ±0.005 in. (±0.01 cm). Hole numbers 8 thru 12 are optional.
(2) Tolerance on the D distance is ±0.005 in. (±0.01 cm).
(3) All dimensions are ±0.03 in. (±0.08 cm) or as noted in (1) and (2).
(4) All dimensions are in inches, except as noted.
(5) Material is ANSI 01 tool steel from annealed round stock.
(6) The ring shall be heat treated as follows: Heat to 1400° to 1450°F (760° to 790°C).
hold at this temperature for one hour. Cool to a maximum rate of 40°F/hr (22°C/hr)
to below 1000°F (540°C). Furnace or air cool to room temperature. Finish the ring
to RMS 25 and protect from corrosion.
(7) Notes (1) thru (6) apply to KETOS test rings.
(8) Notes (1) thru (4) apply to AS 5282 test rings. Except as specified above, AS 5282
test rings shall meet the requirements of AS 5282.
*Figure 1 - KETOS and AS 5282 Test Rings

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3.11.1.3 Particle Concentration. The concentration of particles in the

test bath shall be as specified in the written procedure. Particle
concentrations outside the range of 0.1 ml to 0.4 ml in a 100 ml bath sample
for fluorescent particles shall not be used unless authorized by the
Certifying Agent. Fluorescent and nonfluorescent particles shall not be used
together.

3.11.1.4 Conditioned Water Vehicle. When water is used as a suspension

vehicle for magnetic particles, it shall be suitably conditioned to provide
for proper wetting, particle dispersion, and corrosion protection. Proper
wetting shall be determined by the water break test (see 5.5.1.1.4).
Generally, smoother test surfaces require a greater percentage of wetting
agent be added than rough surfaces. Nonionic wetting agents are recommended.
However, in all instances the wetting agent additions shall be controlled by
pH measurements limiting the alkalinity of the suspension to a maximum pH of
10.0 and an acidity to a maximum pH of 6.0.

*3.12 Accessibility. Drawings which invoke this specification require

the inspection of 100% of the part surfaces (internal and external) except as
noted below or as explicitly defined on the drawing. A valid magnetic
particle inspection requires all of the following:

(a) Adequate visual access (See Figure 2)

(b) Ability to confirm that indications are relevant
(c) Ability to measure relevant indications against the specified
limits
(d) Ability to properly apply the MPI process materials in the times
required in this specification.

Human Eye

Optimum line of sight is perpendicular to surface

to be inspected. Adequate visual access can be
achieved within 45 degrees of that perpendicular
line of sight.

- 45 deg + 45 deg

Surface to be inspected

FIGURE 2

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*3.12.1 Excluded Features. A valid magnetic particle inspection cannot be

performed on certain features. These features have geometric configuration
limitations which either prevent visual inspection of the surfaces, (even
with special equipment) or do not permit interpretation or measurement. The
following features are excluded from MPI inspection:
(a) Honeycomb surfaces
(b) Surfaces inside closed volumes or obstructed by assembly which
have been previously inspected as detail parts
(c) Features with openings smaller than 0.25 inches (6.4 mm) in any
dimension.
(d) Blade and vane internal passages/cavities.
(e) Internal cast, cored passages in non-blade and vane castings with
openings smaller than 0.25 inches (6.4 mm) in any dimension.

3.12.2 Features Requiring Special Equipment. Optimum visual access

occurs when the line-of-sight is perpendicular to the surface being inspected
(see Figure 2). In areas where visual access results in a line of sight
viewing angle greater than 45 degrees from a line perpendicular to the
surface being inspected, or where the surface to be inspected extends beyond
a depth to opening ratio greater than 1, or where other limitations prevent a
valid unaided inspection (i.e. cannot meet 3.12), special equipment such as
mirrors, borescopes, measuring devices, etc. shall be considered to meet the
requirements of the inspection. Type and use of special equipment, method of
indication evaluation, and area of the part requiring use of the special
equipment shall meet all other requirements of this specification and shall
be defined in the MPI work instructions.

*3.12.3 Uninspectable Features. Any area(s) other than 3.12.1 that the
Supplier considers uninspectable (i.e., cannot meet 3.12) after evaluating in
accordance with 3.12.2, shall be identified and submitted to the Purchaser as
a request for a drawing or specification change. For both GE Aviation and
Vendor design, an issued change document against the drawing or
specification, or both, shall be required prior to shipment. (Reference
information: for GE Aviation designed parts, the Supplier shall document the
problem via the Source Problem Reports (GT3601) system; for Vendor designed
items, the Vendor shall document the problem via the Request for Design
Change System (RDC)).

3.12.4 Threaded Holes. Threaded holes shall be fluorescent magnetic

particle inspected for indications oriented transverse to the thread profile.
Unless acceptability limits for threaded holes are stated on the drawing or
in another acceptability limit specification that is invoked on the drawing,
transverse indications extending over more than one thread are rejectable.
All other indications are considered nonrelevant.

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4. DETAIL REQUIREMENTS

4.1 Preparation of Parts for Inspection

4.1.1 Pre-Inspection Demagnetization. The part shall be demagnetized

before inspection if prior operations have produced a residual magnetic field
which will interfere with the inspection.

4.1.2 Surface Cleanliness and Finish. The surface of the part to be

inspected shall be smooth, clean, dry, and free of oil, scale, machining
marks, or other contaminants or conditions which might interfere with the
efficiency of the inspection.

4.1.3 Coatings. Magnetic particle inspection shall not be performed with

coatings in place that could prevent the detection of surface defects in a
ferromagnetic substrate. Thin non-ferromagnetic coatings, which do not
exceed 0.003 inch (0.08 mm) in thickness and ferromagnetic coatings not
exceeding 0.001 inch (0.03 mm) in thickness which do not interfere with the
inspection may be left on in-service components during inspection. When such
coatings are non-conductive, they shall be removed where electrical contact
is to be made. Production parts shall be magnetic particle inspected before
the application of coating and before and after plating when required by the
drawing.

4.1.4 Plugging and Masking. Small openings and oil holes leading to
obscure passages or cavities shall be plugged with a non-abrasive material
which is easily removed and, in the case of engine parts, is soluble in oil.
Effective masking shall be used to protect those components, such as certain
non-metallics, which may be damaged by contact with the suspension.

4.2 Magnetizing Methods

*4.2.1 Yokes and Permanent Magnets. Yokes and permanent magnets shall
not be used for magnetic particle inspection unless use is approved by the
Purchaser.

4.2.2 Types of Magnetizing Current. The types of magnetizing current

used for wet magnetic particle inspection are full-wave rectified three phase
current (FWDC), half-wave rectified single phase current (HWDC), and
alternating current (AC). AC shall be used only for the detection of defects
open to the surface. FWDC has the deepest possible penetration and shall be
used when inspecting for defects below the surface using the wet magnetic
particle method.

4.2.3 Magnetic Field Directions. To assure the detection of

discontinuities in any direction, magnetization shall be applied to the part
from at least two perpendicular directions. Magnetization may be applied
from one direction with approval of the Purchaser. The magnetization fields
shall be created by using circular magnetization in two or more directions,
both circular and longitudinal magnetization, or longitudinal magnetization
in two or more directions. Exceptions, using multidirectional (see 4.2.4)

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magnetization when necessitated by part geometry, size or other factors. If

multidirectional magnetization is used, it shall be demonstrated that it is
effective in all critical areas and shall require approval by the Purchaser.
Parts shall be demagnetized between shots when the first current level is
higher than the second.

*4.2.4 Multidirectional Magnetization. With suitable circuitry a

multidirectional field in a part may be established (for example, by
selectively switching the magnetizing current between contact pairs
positioned approximately 90 degrees apart). In using this method, the
particle application shall be timed so that the magnetization reaches its
full value in all directions during the time the particles are mobile on the
surface of the part under test.

4.2.5 Direct Magnetization. When direct magnetization is used,

precautions shall be taken to assure that an electrical current is not
flowing while contacts are being applied or removed, and that excessive heat
does not occur in the contact area. Prods shall not be used for the
inspection of aerospace components or on finished surfaces. Contact pads
shall be maintained in a condition to prevent arcing on the part.

4.2.6 Indirect Magnetization. Indirect part magnetization shall use pre-

formed coils, cable wraps, yokes, or a central conductor to produce a
magnetic field of suitable strength and direction to magnetize the part under
test. Central conductors shall be in good condition, straight with smooth
surfaces and ends.

4.2.7 Induced Current Magnetization. Induced current magnetization

(toroidal or circumferential field) is accomplished by inductively coupling a
part to an electrical coil to create a suitable current flow in the part as
illustrated in Figure 3. This method is often advantageous on ring shaped
parts with a diameter to thickness ratio greater than 5, especially where
elimination of arcing or burning is of vital importance. This method shall
be used only with approval by the Purchaser.

*4.2.8 Magnetic Field Strength. The applied magnetic field shall have
sufficient strength to produce satisfactory indications but shall not be
strong enough to cause masking of relevant indications by nonrelevant
accumulations of magnetic particles. Factors which determine the required
field strength shall include the size, shape, and material permeability of
the part, the technique of magnetization, the method of particle application
and the type and location of defects sought. The proper magnetization levels
may be determined by one or a combination of three methods:

(a) By testing parts having known defects of the type, size and
location specified in the acceptance requirements
(b) By using a Hall-effect probe gaussmeter capable of measuring the
peak values of the tangential field. Tangential applied field
strength levels for magnetic particle inspection shall be in the
range of 30 to 60 gauss (2.4 to 4.8 KAm-1) and shall be present in
all areas to be inspected on the part. (See 8.2)

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(c) By use of the formulas given in 4.2.14.1 through 4.2.14.4

*4.2.9 Magnetizing Current Levels. When a current range is given, the

largest value listed shall be used unless the value causes interference due
to nonrelevant indications, or overheating of the part. Unless otherwise
approved by the Purchaser, the field strength levels shall be maintained
between 30 and 60 gauss (2.4 and 4.8 KAm-1) in the area to be inspected, when
verified in accordance with 4.2.8(b)

*4.2.10 Direct Circular Magnetization. When magnetizing by passing

current directly through the part (i.e. using "head shots") the current shall
be from 300 A/inch of part diameter to 800 A/inch of part diameter (12 A/mm
to 32 A/mm). The diameter of the part shall be taken as the largest distance
between any two points on the outside circumference of the part. Normally
currents will be 500 A/inch (20 A/mm) or lower with the higher currents up to
800 A/inch (32 A/mm) being used to inspect for inclusions or to inspect
alloys such as 15-5 PH steel. Additionally, the provisions of 4.2.9 shall
apply.

The primary current sets up an oscillating field. This primary magnetic field induces a current in the
ring shaped part under test.

*Figure 3 - Example of Induced Current Magnetization

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 P3TF48-S3

4.2.11 Central Conductor Circular Magnetization. Circular magnetization

may be provided by passing current through a conductor which passes through
the inside of the part. In this case, alternating current is to be used only
when the sole purpose of the test is to inspect for surface discontinuities
on the inside surface of the part. If only the inside of the part is to be
inspected, the diameter shall be the largest distance between two points, 180
degrees apart on the inside circumference; otherwise the diameter shall be
determined as specified in 4.2.10.

4.2.12 Centrally Located Conductor. When the axis of the central

conductor is located near the central axis of the part, the same current
levels as specified in 4.2.10 shall apply.

4.2.13 Offset Central Conductor. When the conductor passing through the
inside of the part is placed against an inside wall of the part, the current
levels as specified in 4.2.10 shall apply except that the diameter shall be
considered the sum of the diameter of the central conductor and twice the
wall thickness. The distance along the part circumference (interior or
exterior) which is effectively magnetized shall be taken as four times the
diameter of the central conductor as illustrated in Figure 4. The entire
circumference shall be inspected by rotating the part on the conductor,
allowing for approximately a 10 percent magnetic field overlap.

Figure 4 - The Effective Region of Inspection When Using an Offset Central

Conductor is Equal To 4 Times The Diameter of The Conductor as Indicated

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 P3TF48-S3

4.2.14 Longitudinal Magnetization. Longitudinal magnetization shall be

accomplished by passing current through a coil encircling the part, or
section of the part to be tested (i.e. by using a "coil shot"). This
produces a magnetic field parallel to the axis of the coil. For low fill
factor coils the effective field shall extend a distance on either side of
the coil center, which is approximately equal to the radius of the coil (see
Figure 5). For cable wrap or high fill factor coils, the effect distance of
magnetization shall be 9 inches (230 mm) on either side of the coil center
(see Figure 6). For parts longer than these effective distances, the entire
length shall be inspected by repositioning the part within the coil, and
allowing for approximately 10 percent effective magnetic field overlap.

*4.2.14.1 Longitudinal Magnetization with Low Fill Factor Coils. When

the cross sectional area of the coil is 10 or more times the cross sectional
area of the part being inspected, then the product of the number of coil
turns, N, and the current in amperes through the coil, I, shall be:

(a) For parts position to the side of the coil;

NI = K (±10 percent)
L/D

where, K = 45,000 ampere turns

L = length of the part
D = diameter of the part (measured in the same units as the length)

Figure 5 - Effective Region of Inspection For a Low Fill Factor Coil

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 P3TF48-S3

Figure 6 - Effective Region of Inspection For a High Fill Factor Coil

(b) For parts position in the center of the coil;

NI = KR (±10 percent)
(6L/D) - 5

where, R = radius of the coil in inches (or in mm)

K = 43,000 ampere turns per inch (1690
ampere turns if R is measured in mm)
L = length of the part
D = diameter of the part (measured in the
same units as the length)

If the part has hollow portions, replace D with Deff as specified in 4.2.14.4.
These formulas hold only if L/D is greater than 3 and less than 15. If L/D
is less than 3, poles pieces (pieces of ferromagnetic material with the same
diameter as the part being tested) shall be placed on each end of the part to
effectively increase L/D to 3 or greater. If L/D is greater than 15 the
value of 15 shall be substituted for L/D.

*4.2.14.2 Longitudinal Magnetization with Cable Wrap or High Fill Factor

Coils. When the cross sectional area of the coil is less than twice the
cross sectional area (including hollow portions) of the part being inspected,
then the product of the number of coil turns, N, and the current in amperes
through the coil, I, shall be:

NI = K (±10 percent)
(L/D) + 2

where, K = 35,000 ampere turns

L = length of the part
D = diameter of the part (measured in the
same units as the length)

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If the part has hollow portions, replace D with Deff as specified in 4.2.14.4.
These formulas hold only if L/D is greater than 3 and less than 15. If L/D
is less than 3, poles pieces (pieces of ferromagnetic material with the same
diameter as the part being tested) shall be placed on each end of the part to
effectively increase L/D to 3 or greater. If L/D is greater than 15 the
value of 15 shall be substituted for L/D.

*4.2.14.3 Longitudinal-Magnetization for Intermediate Fill Factor Coils.

When the cross sectional area of the coil is between two times and ten times
the cross sectional area of the part being inspected, the product of the
number of coil turns, N, and the current in amperes through the coil, I,
shall be:

NI = (NI)h 10-γ + (NI)e γ-2

8 8

where (NI)e = the value of NI calculated for low fill factor coils
using 4.2.14.1
(NI)h = the value of NI calculated for high fill factor coils
using 4.2.14.2

γ = the ratio of cross sectional area of the coil to the

cross sectional area of the part. (For example, if the
coil is 10 inches in diameter and the part is a rod 5
inches in diameter

γ = ( π * 52) / (π * 2.52) = 4.

*4.2.14.4 Calculating the L/D Ratio for a Hollow or Cylindrical Part.

When calculating the L/D ratio for a hollow or cylindrical part, D shall be
replaced with an effective diameter, Deff calculated as follows:

Deff = 2 [(At - Ah) / π]1/2

where At = the total cross sectional area of the part

Ah = the cross sectional area of the hollow portions of the part

For a cylindrical part this is equal to:

Deff = [ (OD)2 - (ID)2 ]1/2

where OD = the outside diameter of the cylinder

ID = the inside diameter of the cylinder

*4.3 Wet Magnetic Particle Application - Continuous Method. Fluorescent

particles suspended in a liquid vehicle at the required concentration shall
be applied either by gently spraying or flowing the suspension over the area
to be inspected. Proper sequencing and timing of the part magnetization and
application of the particle suspension are required to obtain proper
formation and retention of indications. This generally requires that the
stream of suspension be diverted from the part simultaneously with, or

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 P3TF48-S3

slightly before, energizing the magnetic circuit. The magnetizing current

shall be applied for a duration of at least 0.5 second for each application
with a minimum of two shots for each direction being used. After application
of current and suspension, the area is ready for inspection. In some cases it
would be beneficial to allow the area to be inspected to dwell for a period
of time to allow for the complete formation of indications Areas requiring a
dwell time shall be determined and included in the written procedure by the
MPI Level III at the testing facility. Care shall be exercised to prevent
any damage to the part due to overheating or other causes. Weakly held
indications on highly finished parts are readily washed away and hence care
shall be exercised to prevent high velocity flow over critical surfaces. Re-
application of suspension, as in verification of indications, shall be done
only while the magnetizing current is on. Re-application of suspension shall
not be done based on residual magnetism.

4.4 Interpretation of Indications

4.4.1 Types of Indications. Indications produced during magnetic

particle inspection shall be divided into the following types: false
indications, nonrelevant indications and relevant indications. The part
shall be demagnitized and reinspected as needed, to verify indications
thought to be false or nonrelevant.

4.4.1.1 False and Nonrelevant Indications. Those indications determined

to be false or nonrelevant require no further action and are not required to
be documented on the inspection report.

4.4.1.2 Evaluation. Relevant indications that exceed the specific

acceptance criteria for the component shall be cause for rejection.

*4.4.1.3 Measurement. Size of indication shall be determined through

the use of calibrated feeler gages or calibrated pin gages with an accuracy
of +/- 0.002 inches (+/- 0.005 cm). These will be placed directly over the
indication to assess size. The smallest feeler gage/ pin gage that
completely covers the indication will be used to determine size. Gage sizes
shall be within +/- 0.0025 inches (+/- 0.0064 cm) of acceptance criteria.
Other measurement devices may be used with prior Purchaser approval.

4.4.2 Recording of Indications. When required by the written procedure,

the location of all rejectable indications shall be marked on the part and a
permanent record of the location, direction and frequency of indications
shall be made by one or more of the following methods.

4.4.2.1 Written Description. By recording the location, length,

direction, and number of indications by a sketch or in a tabular form.

4.4.2.2 Photography. By photographing or video recording the indications

themselves, and placing the photograph on a tabular form along with
information giving its location on the part.

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 P3TF48-S3

4.5 Post-Inspection Procedures. All parts shall be demagnetized,

cleaned, corrosion protected and marked after inspection.

*4.5.1 Demagnetization. When using AC demagnetization, the part shall be

subjected to a field with a peak value greater than, and in nearly the same
direction as the field used during inspection, then the field shall be
gradually reduced to zero. Next, using an AC demagnetizing coil, hold the
part approximately 1 foot (0.30 m) in front of the coil and then move it
slowly and steadily through the coil and at least 3 feet (0.91 m) beyond the
end of the coil. This process shall be repeated as necessary. Parts of
complex configuration shall be rotated and tumbled while being passed through
the field of the coil. When using direct current (DC) demagnetization, the
initial field shall be higher than and in nearly the same direction as, the
field reached during inspection. The field shall then be reversed, decreased
in magnitude, and the process repeated (cycled) until an acceptably low value
of residual magnetic field is reached. Whenever possible, parts which have
been circularly magnetized shall be magnetized in the longitudinal direction
before being demagnetized. After demagnetization, a magnetic field probe or
strength meter shall be used to verify that residual magnetism has been
reduced to an absolute value no greater than 3 gauss, anywhere on the part.

4.5.2 Post Inspection Cleaning. Parts shall be cleaned by the use of a

suitable solvent, air blower, or by other means. All traces of the magnetic
particles and magnetic particle test materials which might interfere with
subsequent use of the part shall be removed (chlorinated solvents shall not
be used on parts containing crevices). Parts shall be inspected to ensure
that the cleaning procedure has removed magnetic particle residues from
coolant holes, crevices, passage ways, etc., since such residues could have
an adverse effect on the intended use of the part. Care shall be taken to
remove all plugs, masking or other processing aids that may affect the
intended use of the part. Parts shall be protected from any possible
corrosion or damage during the cleaning process and shall be treated to
prevent the occurrence of corrosion after final inspection.

4.6 Marking of Inspected Parts. Unless otherwise specified by the

Purchaser, parts which have been accepted using magnetic particle inspection
shall be marked in accordance with the applicable contract documents.
Marking shall be applied in such a manner and location as to be harmless to
the part. The identification shall not be obliterated or smeared by
subsequent handling and, when practicable, shall be placed in a location
which will be visible after assembly. When subsequent processing would
remove the identification, the applicable marking shall be affixed to the
record accompanying the finished parts or assembly. If quality records
provide traceability from router to hardware, then part marking may be
replaced by marking the router. Bolts and nuts and other fastener products
may be identified as having met the requirements of magnetic particle
inspection by conspicuously marking each package.

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 P3TF48-S3

4.6.1 Impression Stamping, Laser Marking, or Vibro Engraving. Impression

stamping, laser marking, or vibro engraving shall be used when permitted or
required by the applicable written procedure, detail specification or
drawing, or when the nature of the part is such as to provide for impression
stamping of part numbers or other inspector markings. Impression stamping
shall be located only in the area provided adjacent to the part number or
inspector's stamp unless otherwise specified by the Purchaser.

4.6.2 Etching. When impression stamping or vibro engraving is

prohibited, parts shall be etched using an etching fluid or other means and a
method of application approved by the Purchaser. The etching process and
location shall not adversely affect the functioning of the part.

4.6.3 Dyeing. When stamping, vibro engraving or etching is not

permissible, identification shall be accomplished by dyeing.

4.6.4 Other Identification. Other means of identification such as

tagging, shall be used for parts which have a construction or function
precluding the use of stamping, laser marking, vibro engraving or etching, as
in the case of completely ground or polished balls, rollers, pins, or
bushings.

4.6.5 Identifying Symbols and Color Markings

4.6.5.1 100-Percent Inspection. When items are inspected and accepted by

100-percent inspection, each item shall be marked as follows:

4.6.5.1.1 Dyeing. When dyeing is applicable, a dye of acceptable

adherence which is predominately blue in accordance with FED-STD-595 shall be
employed. However, if a color conflict is incurred with an other method,
magnetic particle inspection can be indicated by two adjacent blue dots or
other suitable means.

*4.6.5.1.2 Stamping, Laser Marking, Vibro Engraving or Etching. When

impression stamping, laser marking, vibro engraving or etching is used to
mark 100-percent inspected parts, the letter "M" with a circle around it
shall be employed.

4.6.5.2 Lot Inspection. When items are accepted by means of a sampling

procedure, each item of an accepted lot shall be marked as follows:

4.6.5.2.1 Dyeing. When dyeing is applicable, a dye of acceptable

adherence which is predominately orange in accordance with FED-STD-595 shall
be employed.

*4.6.5.2.2 Stamping, Laser Marking, Vibro Engraving or Etching. When

impression stamping, laser marking, vibro engraving or etching is used to
mark lot-inspected parts, the letter "M" shall be employed.

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5. QUALITY ASSURANCE PROVISIONS

*5.1 Inspection System Verification. This section provides the controls

necessary to assure that the magnetic particle system materials and equipment
provide an acceptable level of performance. The frequency of the required
checks is based upon a facility operating for a full, one-shift-operation
daily. For facilities operating less frequently, the frequency of daily and
weekly checks may be reduced, but shall be performed prior to inspections.
Other checks should be performed at the same frequency as for full time
operations. The NDT facility may perform these process control operations or
contract for their performance with an independent laboratory. Results of
all required checks shall be documented.

5.2 Black Lights. All black lights shall be checked daily, and after
bulb replacement, for output. A longer period may be used if a plan
justifying this extension is prepared by the NDT facility and approved by the
contracting agency. Minimum acceptable intensity is 1200 micro watts/cm2
measured at a distance of at least 15 inches (38 cm) from the front of the
bulb or filter. Black light reflectors and filters shall be checked daily
for cleanliness and integrity. Damaged or dirty reflectors or filters shall
be replaced or corrected as appropriate.

*5.2.1 Black Light Borescopes. When black light borescopes are used for
final inspection of hardware, they shall meet the light intensity
requirements of 5.2 and 5.3 except that intensity shall be measured at a
distance no closer than that used for inspection.

*5.3 Visible Light Intensities. Fluorescent magnetic particle inspection

shall be performed in a darkened area with a maximum ambient visible light
level of 2-foot candles (20 lux/m2). Additionally, the white light emission
from ultraviolet lights, used for inspection, shall be measured at 15 inches
(38 cm) from the front of the black light bulb or filter, with the black
light on. The measured emission shall not exceed 2-foot candles (20 lux/m2).

5.4 Known Defect Standards

5.4.1 Use of Test Part with Discontinuities. Representative parts

containing defects of the type, location, and size specified in the
acceptance requirements shall be used to evaluate the inspection procedure.
If magnetic particle indications can be produced and identified in these
representative parts, then the overall system performance and inspection
procedure is verified. Parts used for verification shall be demagnetized and
thoroughly cleaned following the inspection and checked under black light, to
ensure residual indications do not remain.

*5.4.2 Fabricated Test Parts with Artificial Discontinuities. When

actual production parts with known defects of the type, location, and size
needed for verification, are not available or are impractical, then,
fabricated test parts with artificial defects shall be used. Artificial
defects may be fabricated to meet a particular need as shown in Figure 7 or
may be commercially available magnetic field indicators as shown in Figure 8

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 P3TF48-S3

or the Ketos or AS 5282 ring as defined in Figure 1. All applicable

conditions for the use of such test parts, as described in 5.4.1, shall
apply.

5.5 Process Control Checks

5.5.1 Suspension Vehicle Tests. (Not required for aerosol can solutions)

*5.5.1.1 Concentration Tests. Particle concentration and contamination

shall be determined upon start up, at regular intervals thereafter, and
whenever the bath is changed or adjusted. The required testing intervals are
stated in Table II.

5.5.1.1.1 Determination of Wet Particle Concentration, Gravity Method.

Agitate the particle suspension a minimum of 30 minutes to insure a uniform
distribution of particles throughout the bath. Fill a 100 ml pear-shaped
graduated centrifuge tube (of the size and shape specified in ASTM D96,
except graduated to 1 ml in 0.05 ml increments) to the 100 ml mark with the
suspension directly from the hose. Demagnetize the sample and allow the tube
to stand undisturbed for at least 60 minutes if using the petroleum
distillate specified in AMS 2641 or 30 minutes settling time for conditioned
water suspension. Read the volume of settled particles. The volume of the
solids in the tube shall be 0.1 ml to 0.4 ml. Concentrations of 0.15 ml to
0.2 ml will generally provide more contrast by the elimination of excess
fluorescent background. If the concentration is out of the tolerance add
particles or suspension vehicle as required, and redetermine the particle
concentration. If the settled particles appear to be loose agglomerates
rather than a solid layer, take a second sample. If the second sample also
appears agglomerated, replace the entire suspension. After the bath has been
discarded, the sump tank, hose, nozzle, and drain boards shall be cleaned
before a new bath is prepared. Thirty minute settling times, or other
accelerated tests, such as the centrifuge method below, may be used if they
have been verified to give results equivalent to the procedure described in
this paragraph. Equivalency shall be established by processing samples from
the same bath using each method in question. If the comparison of the sample
concentrations obtained are ± 0.01 ml of each other and within acceptable
range, the methods used are considered equivalent.

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Type R

Examples of artificial shims used in magnetic particle inspection system verification.

(Not drawn to scale.) The shims are made of low carbon steel (1005 steel foil). The
artificial flaw is etched or machined on one side of the foil to a depth of 30% of the
foil thickness. In use, the shims are firmly attached to the test part (e.g. with tape
around the edges) with the flaw toward the part.

Figure 7 - Configuration of Artificial Flaws and Their Designation

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*5.5.1.1.2 Determination of Wet Particle Concentration, Centrifuge

Method. Agitate the particle suspension a minimum of 30 minutes to insure a
uniform distribution of particles throughout the bath. Fill a 100 ml pear-
shaped graduated centrifuge tube (of the size and shape specified in ASTM
D96, except graduated to 1 ml in 0.05 ml increments) to the 100 ml mark with
the suspension directly from the hose. Demagnetize the sample and place in a
hand driven centrifuge device. When using the centrifuge device another tube
with an equal volume of water shall be placed into the apparatus to maintain
balance. The apparatus shall be spun until the liquid vehicle is clear
(usually a minute or two) and the particles have settled to the bottom. Read
the volume of settled particles. The volume of the solids in the tube shall
be 0.1 ml to 0.4 ml. If the concentration is out of the tolerance, add
particles or suspension vehicle as required, and redetermine the particle
concentration. If the settled particles appear to be loose agglomerates
rather than a solid layer, take a second sample. If the second sample also
appears agglomerated, replace the entire suspension. After the bath has been
discarded, the sump tank, hose, nozzle, and drain boards shall be cleaned
before a new bath is prepared.

Figure 8 - Pie Field Indicator For Use in Magnetic Particle Inspection System
Verification

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5.5.1.1.3 Determination of Wet Particle Contamination. Perform one of

the tests specified in 5.5.1.1.1 or 5.5.1.1.2. In addition, for fluorescent
baths, examine the liquid directly above the precipitate with black light.
The liquid shall be essentially non-fluorescent. Examine the graduated
portion of the tube both under black light and under visible light for
striations or bands different in color or appearance. Bands or striation may
indicate contamination. If the total volume of the contaminants, including
bands or striations, exceeds 30% of the volume of the magnetic particles, or
if the liquid is noticeably fluorescent, the bath shall be replaced.

*TABLE II
PROCESS CONTROL CHECKS, FREQUENCY and VALUES
CHECK FREQUENCY VALUE
Black Light Intensity Daily 1200 µw/cm2 at 15
inches (38 cm) minimum
White Light Emission Daily 2 Foot Candles
(20 lux/m2) Maximum
Black Light Borescope Intensity Daily or 1200 µw/cm2 at working
When in use distance used
White Light Borescope Emission Daily or 2 Foot Candles
When in use (20 lux/m2) Maximum at
working distance used
Ambient White Light Weekly 2 Foot Candles
(Background) (20 lux/m2) Maximum
System performance using test Each shift See Table I
piece or ring specimen of Figure 1 system is in use
Wet particle concentration 8 hours or each 0.1 ml to 0.4 ml
shift system is
in use
Wet particle contamination Each shift Less than 30% of total
system is in use volume
Each shift Continuous even film
Water break test
system is in use

Tap Setting verification Daily +/- 10% within selected

setting

Black Light Reflector and Filters Daily Check for Cleanliness

and Integrity
Inspection Area Cleanliness Weekly Free of Fluorescent
Contamination
Ammeter Accuracy 6 months +/- 10% of full scale
Timer control 6 months +/- 0.1 second

Quick Break 2 months Proper functioning

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5.5.1.1.4 Water Break Test. In this test of water based vehicles a clean
part with a surface finish the same as the parts to be tested is flooded with
the conditioned water and the appearance of the surface is noted after the
flooding is stopped. If a continuous even film forms over the entire part,
sufficient wetting agent is present. If the film of the suspension breaks,
exposing bare surface, insufficient wetting agent is present or the part has
not been adequately cleaned. If cleanliness is the cause, the part shall be
cleaned and rechecked. If insufficient wetting agent is the cause, it shall
be adjusted in accordance with 3.11.1.4.

5.5.1.1.5 Viscosity Test. The viscosity of light petroleum distillate

vehicles conforming to AMS 2641 or DOD-F-87935 shall not exceed 5.0
centistokes at the temperature of use when tested in accordance with ASTM D
445.

*5.6 Equipment Calibration. Magnetic particle testing equipment shall be

checked for performance and accuracy at the time of purchase and at intervals
thereafter as specified in Table II, whenever malfunction is suspected and
whenever electrical maintenance which might affect equipment accuracy is
performed. Calibration shall be performed to the requirements of P3TF41 CL-
A.

*5.6.1 Ammeter Accuracy. The equipment ammeter shall be checked at the

time intervals specified in Table II. The equipment ammeter shall be
connected in series with the output circuit of a calibrated ammeter.
Comparative readings shall be taken at three output levels encompassing the
usable range of the equipment. The equipment meter reading shall not deviate
by more than ± 10 percent of full scale from the calibrated ammeter readings
(when measuring HWDC the current values shown by the calibrated meter DC
meter reading shall be doubled).

5.6.2 Timer Control Check. On equipment using a timer to control current

duration, the timer shall be checked to within ± 0.1 second by using an
electronic timer.

5.6.3 Magnetic Field Quick Break Check. For equipment which utilizes a
quick break feature, the proper functioning of this circuit shall be verified
by using an oscilloscope or other applicable method as recommended by the
equipment manufacturer.

5.6.4 Tap Settings. Machines equipped with positive indexing amperage

controls (not continuously variable) shall have each tap setting used for
inspection verified daily by energizing the equipment a minimum of five times
and verifying amperage produced is consistently within ± 10 percent within
the selected setting(s).

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6. SAFETY

*6.1 General. Safe handling of magnetic particles (wet or dry), oil

vehicles, water baths, and water conditioner concentrates are governed by the
suppliers' Material Safety Data Sheets (MSDS). Material Safety Data Sheets,
conforming to 29 CFR 1910.1200, shall be provided by the supplier to any user
and shall be prepared in accordance with FED-STD-313. Proper precautions
shall be taken to prevent the ignition of hydrocarbon suspension baths by
overheating, electrical arcing, etc. In addition, precautions shall be taken
to prevent the inhaling of dry particle materials. The use of face masks is
recommended; and, it is recommended that the intensity of black light
incident upon the inspector's unprotected skin or eyes, not exceed 1000
microwatts/cm2.

6.2 Flammability. Flash point of oil vehicles shall be in accordance

with AMS 2641 or DOD-F-87935. The suppliers' MSDS shall certify the flash
point.

6.3 Personnel Hazards. Precautions against inhalation, skin contact, and

eye exposure are detailed in the suppliers' MSDS. These precautions shall be
observed.

6.4 Electrical Hazards. Magnetizing equipment shall be properly

maintained to avoid personnel hazards from electrical short circuits.

7. PACKAGING

This section is not applicable

8. NOTES

*8.1 Purpose. This section contains information of a general nature,

which may be helpful, but is not mandatory. It does not contain any
requirements.

*8.2 Measurement of Tangential Field Strength. Care must be exercised

when measuring tangential applied field strengths. The active area of the
Hall-effect probe should be no larger than 0.20 inch (5 mm) by 0.20 inch (5
mm) and should have a maximum center location 0.20 inch (5 mm) from the part
surface. The plane of the Hall-effect element must be perpendicular to the
surface of the part at the location of measurement to within 5 degrees. This
is difficult to accomplish by hand orientation and the probe should be held
in a jig or fixture of some type. If the current is being applied in shots,
or if alternating current or half wave rectified alternating current is being
used, the gaussmeter should be set to read the peak value during the shot.
The gaussmeter should have a frequency response of 0 to 300 HZ or higher.
The direction and magnitude of the field can be determined by two

28
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 P3TF48-S3

measurements made at right angles. The gaussmeter probe leads should be

shielded or twisted to prevent reading errors due to voltage induced during
large field changes encountered during magnetic particle inspection.

*8.3 Alternative Inspection Procedures. The approval of alternative

inspection procedures is based upon the Purchaser approving the procedure as
being equal to or better than the magnetic particle inspection requirements
of this specification. The alternative procedures may allow variances in
processing details; but are still required to meet the technical requirements
specified for the part(s).

*8.4 Inspection Planning Flowchart. The Inspection planning process

shown in Figure 9 is a guide to establish the Inspection Plans.

*8.5 Certifying Agent. Certifying Agents are approved in accordance with

GE Aviation Procedure 259.01, Control of Special Processes.

29
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 P3TF48-S3

Choose surface (or next

surface)

Yes
All surfaces Planning
been Complet
considered? e

No

Yes Excluded
features per
MPI Inspection not
3.12.1 or as
required on surface defined on
drawing

Document surface does not Finalize MPI work instructions for

No
require inspection in the MPI surface based on SPR or RDC
work instructions response :

View angle> -Formal design change specifying

Yes 45 degrees alternative NDE method or
from exclusion of surface from P3TF48
perpendicular
inspection
-Reconsider alternative special
No equipment
Yes
Depth to
opening ratio >
1?

NO
Yes Can all 4 criteria in
3.12 for valid No
inspection be met Submit SPR (GT3601) or RDC
using special Surface Uninspectable
equipment?
No

All four (4)

criteria in 3.12
can be met for
Document use (surface and equipment) valid
in MPI work instructions inspection?

Yes

No special callout req’d in the

MPI work instructions for this
surface

Figure 9 - P3TF48 Planning Flowchart

30
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 P3TF48-S3

REVISION HISTORY

P3TF48-S1 INITIAL ISSUE 11-19-98

-S2 DCID 078882 02-14-00
-S3 CID 558240 10-25-11

*Denotes latest revision

31
GE PROPRIETARY INFORMATION
Use or disclosure of data contained on this sheet is subject to the restrictions on the cover or first page.