ASTM E1444-94A

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1444 – 94a An American National Standard
Standard Practice for
Magnetic Particle Examination
This standard is issued under the fixed designation E 1444; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This specification has been approved for use by agencies of the Department of Defense.
1. Scope SNT-TC-1A Recommended Practice and Supplement Mag-
netic Particle Inspection
1.1 This practice establishes minimum requirements for
2.4 Society of Automotive Engineers (SAE)-AMS Docu-
magnetic particle examination used for the detection of surface
ments:
or slightly subsurface discontinuities in ferromagnetic material.
AMS 2300 Premium Aircraft-Quality Steel Cleanliness
This practice is intended as a direct replacement of MIL-STD-
Magnetic Particle Inspection Procedure
1949. Guide E 709 can be used in conjunction with this
AMS 2301 Aircraft Quality Steel Cleanliness Magnetic Par-
practice as a tutorial.
ticle Inspection Procedure
1.2 The magnetic particle examination method is used to
AMS 2303 Aircraft Quality Steel Cleanliness Martensitic
detect cracks, laps, seams, inclusions, and other discontinuities
Corrosion Resistant Steels Magnetic Particle Inspection
on or near the surface of ferromagnetic materials. Magnetic
Procedure
particle examination may be applied to raw material, billets,
AMS 2641 Magnetic Particle Inspection Vehicle
finished and semifinished materials, welds, and in-service
AMS 3040 Magnetic Particles, Nonfluorescent, Dry
parts. Magnetic particle examination is not applicable to
Method
nonferromagnetic metals and alloys such as austenitic stainless
AMS 3041 Magnetic Particles, Nonfluorescent, Wet
steels.
Method, Oil Vehicle, Ready-To-Use
1.3 This standard does not purport to address all of the
AMS 3042 Magnetic Particles, Nonfluorescent, Wet
safety concerns, if any, associated with its use. It is the
Method, Dry Powder
responsibility of the user of this standard to establish appro-
AMS 3043 Magnetic Particles, Nonfluorescent, Wet
priate safety and health practices and determine the applica-
Method, Oil Vehicle, Aerosol Packaged
bility of regulatory limitations prior to use.
AMS 3044 Magnetic Particles, Fluorescent, Wet Method,
2. Referenced Documents Dry Powder
AMS 3045 Magnetic Particles, Fluorescent, Wet Method,
2.1 The following documents form a part of this standard
Oil Vehicle, Ready-To-Use
practice to the extent specified herein.
AMS 3046 Magnetic Particles, Fluorescent, Wet Method,
2.2 ASTM Standards:
Oil Vehicle, Aerosol Packaged
A 275/A 275M Test Method for Magnetic Particle Exami-
AMS 5355 Investment Castings
nation of Steel Forgings
2.5 Federal Standards:
A 456 Specification for Magnetic Particle Inspection of
FED-STD-313 Material Safety Data Sheets, Preparation
Large Crankshaft Forgings
and the Submission of
D 96 Test Methods for Water and Sediment in Crude Oil by
FED-STD-595 Colors
the Centrifuge Method (Field Procedure)
2.6 Military Standards:
E 543 Practice for Evaluating Agencies that Perform Non-
MIL-STD-1907 Inspection, Liquid Penetrant and Magnetic
destructive Testing
Particle Soundness Requirements for Materials, Parts, and
E 709 Guide for Magnetic Particle Examination
Weldments
E 1316 Terminology for Nondestructive Examinations
2.3 ASNT Document:
Available from American Society for Nondestructive Testing, 1711 Arlingate
Plaza, P.O. Box 28518, Columbus, OH 43228-0518.
This practice is under the jurisdiction of ASTM Committee E-7 on Nonde-
Copies of standards, specifications, drawings, and publications required by
structive Testing and is the direct responsibility of Subcommittee E07.03 on Liquid
manufacturers in connection with specification acquisition should be obtained from
Penetrant and Magnetic Particle Methods.
Current edition approved Nov. 15, 1994. Published January 1995. Originally the contracting activity or as directed by the contracting officer.
published as E 1444 – 91. Last previous edition E 1444 – 94. Available from Society of Automotive Engineers, 400 Commonwealth Drive,
Annual Book of ASTM Standards, Vol 01.05. Warrendale, PA 15096.
3 8
Annual Book of ASTM Standards, Vol 05.01. Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Annual Book of ASTM Standards, Vol 03.03. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1444
MIL-STD-410 Nondestructive Testing Personnel Qualifica- tions. Maximum detectability occurs when the discontinuity is
tion and Certification positioned perpendicular to the magnetic flux. In order to
MIL-STD-1949 Magnetic Particle Inspection, Method of detect discontinuities in all directions, at least two magnetic
MIL-STD-2175 Castings, Classification and Inspection of fields, perpendicular to one another in a plane parallel to the
MIL-STD-45662 Calibration Systems Requirements surface being inspected, shall be used, except when specifically
MIL-I-83387 Inspection Process, Magnetic Rubber exempted by the contracting agency.
DoD-F-87935 Fluid, Magnetic Particle Inspection, Suspen-
5. General Practice
sion (Metric)
2.7 OSHA Document:
5.1 Acceptance Requirements—The acceptance require-
29CFR 1910.1200 Hazard Communication
ments applicable to the part or group of parts shall be
2.8 DoD Contracts—Unless otherwise specified, the edi-
incorporated as part of the written procedure either specifically
tions of the documents that are DoD adopted are those listed in
or by reference to other applicable documents, such as MIL-
the issue of the DoDISS (Department of Defense Index of
STD-1907, containing the necessary information. Applicable
Specifications and Standards) cited in the solicitation.
drawings or other documents shall specify the acceptance size
and concentration of discontinuities for the component, with
2.9 Order of Precedence—In the event of conflict between
zoning of unique areas as required by design requirements.
the text of this practice and the referenced documents cited
These acceptance requirements shall be as approved on or as
herein, the text of this practice takes precedence.
specified by the contracting agency. Methods for establishing
acceptance requirements for large crankshaft forgings are
covered in Specification A 456. Methods for establishing
3. Terminology
requirements for steel forgings are covered in Test Method
3.1 Definitions—The definitions relating to magnetic par-
A 275/A 275M. Methods for classifying metal castings are
ticle examination, which appear in Terminology E 1316, shall
given in MIL-STD-2175 and AMS 5355. MIL-STD-1907 pro-
apply to the terms used in this practice.
vides a classification scheme for ferromagnetic forgings, cast-
3.2 Definitions of Terms Specific to This Standard:
ings, extrusions, and weldments.
3.2.1 alternating current (ac)—an electrical current that
5.1.1 Aircraft-Quality Steel Cleanliness—The examination
reverses its direction of flow at regular intervals.
of aircraft-quality steel for cleanliness using magnetic particle
3.2.2 ambient light—the visible light level measured at the
examination shall be as specified in AMS 2300, 2301, or 2303
specimen surface with the black light(s) on.
as appropriate to the type of steel being inspected. However,
3.2.3 contracting agency—a prime contractor, subcontrac-
inspection of parts fabricated from this material shall be in
tor, or government agency procuring magnetic particle inspec-
accordance with the requirements of this practice.
tion services.
5.2 Personnel Qualification—Personnel performing exami-
3.2.4 gauss (G)—the unit of flux density or induction in the
nations in accordance with this practice shall be qualified and
−4
cgs electromagnetic unit system (1 G 5 10 Tesla (T); in air,
certified in accordance with ASNT Personnel Qualification
1 G is equivalent to 1 oersted (Oe), which equals 79.58 A/m).
SNT-TC-1A or MIL-STD-410 for military purposes, or as
3.2.5 head shot—the production of circular magnetization
specified in the contract or purchase order.
by passing current directly through the part being inspected, or
5.3 Agency Qualification—The agency performing the test-
central conductor, while being held in contact with the head
ing or examination shall meet, as a minimum, the requirements
stocks in a horizontal wet machine.
of Practice E 543.
3.2.6 magnetic flux—a conceptualization of the magnetic
5.4 Written Procedure—Magnetic particle examination
field intensity based on the line pattern produced when iron
shall be performed in accordance with a written procedure
filings are sprinkled on paper laid over a permanent magnet.
applicable to the parts or group of parts under testing. The
The magnetic field lies in the direction of the flux lines and has
procedure shall be in accordance with the requirements and
an intensity proportional to the line density.
guidelines of this practice. The procedure shall be capable of
3.2.7 magnetization—the process by which the elementary
detecting the smallest rejectable discontinuities specified in the
magnetic domains of a material are predominantly aligned in
acceptance requirements. The written procedure may be gen-
one direction.
eral if it clearly applies to all of the specified parts being tested
3.2.8 retentivity—the ability of a material to retain magne-
and meets the requirements of this practice. All written
tism after the magnetizing force has been removed.
procedures shall be approved by an individual qualified and
certified at Level III for magnetic particle examination in
4. Significance and Use
accordance with 5.2. Procedures shall be submitted to the
4.1 Magnetic particle examination consists of magnetizing
contracting agency when requested.
the area to be inspected, applying suitably prepared magnetic
5.4.1 Elements of the Written Procedure—The written pro-
particles while the area is magnetized, and subsequently
cedure shall include at least the following elements, either
interpreting and evaluating any resulting particle accumula-
directly or by reference to the applicable documents:
5.4.1.1 Procedure identification number and the date it was
9 written;
Available from Superintendent of Documents, U.S. Government Printing
Office, Washington, D.C. 20402. 5.4.1.2 Identification of the parts to which the procedure
E 1444
applies; this shall include the material and alloy of which the fluorescent magnetic particle examinations shall be performed
parts are fabricated; in a darkened area with a maximum ambient visible light level
of 2 fc (20 lx) measured at the part surface.
5.4.1.3 Sequence of magnetic particle examination as re-
lated to manufacturing process operation, if applicable; 5.7.1.2 Special Visible Internal Light Source—When exami-
nations of internal surfaces must be performed using special
5.4.1.4 Identification of test parts used for system perfor-
visible light sources, the image produced must have sufficient
mance verification (see 7.1.2 and 7.1.3);
resolution to effectively evaluate the required discontinuities.
5.4.1.5 Areas of the part to be examined (include an
Light intensity shall be measured at the expected working
illustration–either sketch or photo);
distance of the equipment.
5.4.1.6 Part preparation required before testing;
5.7.2 Black Lights—All black lights shall be checked at the
5.4.1.7 Directions for positioning the item with respect to
intervals specified in Table 1, and after bulb replacement, for
the magnetizing equipment;
output. A longer period may be used if a plan justifying this
5.4.1.8 The type of magnetizing current and the equipment
extension is prepared by the nondestructive testing facility and
to be used;
approved by the contracting agency. The minimum acceptable
5.4.1.9 Method of establishing the magnetization (head,
intensity is 1000 μW/cm at the part being examined. Black
coil, prods, yoke, cable wrap, etc.);
light reflectors and filters shall be checked daily for cleanliness
5.4.1.10 Directions of magnetization to be used, the order in
and integrity. Damaged or dirty reflectors or filters shall be
which they are applied, and any demagnetization procedures to
replaced or otherwise corrected as appropriate.
be used between shots;
5.7.3 Internal Part Examination—Where lamps are physi-
5.4.1.11 The current level, or the number of ampere turns, to
cally too large to directly illuminate the examination surface,
be used and the duration of its application;
special lighting shall be used. Internal features such as bores,
5.4.1.12 Type of magnetic particle material (dry or wet,
holes, and passages less than 0.5 in. (12.5 mm) nominal
visible or fluorescent, etc.) to be used and the method and
diameter shall not require magnetic particle examination unless
equipment to be used for its application and, for the case of wet
otherwise specified by the contracting agency.
particles, the particle concentration limits;
5.8 Materials:
5.4.1.13 Type of records and method of marking parts after
5.8.1 Dry Particle Requirements—Dry particles shall meet
examination;
the requirements of AMS 3040. In applying AMS 3040, the
5.4.1.14 Acceptance requirements, to be used for evaluating
particles shall show indications as listed in Table 2 on the test
indications and disposition of parts after evaluation; and
ring specimen of Fig. 1 using the following procedure:
5.4.1.15 Postinspection demagnetization and cleaning re-
5.8.1.1 Place a conductor with a diameter between 1 and
quirements.
1.25 in. (25 and 31 mm) and a length longer than 16 in. (40 cm)
5.5 Examination Sequence—When magnetic particle ex-
through the center of the ring. Center the ring on the length of
amination is specified, it shall be performed after the comple-
the conductor. Magnetize the ring circularly by passing the
tion of operations that could cause surface or near-surface
current specified in Table 2 through the conductor. Using a
defects. These operations include, but are not limited to,
squeeze bulb or other suitable applicator, apply the particles to
forging, heat treating, plating, passivation, cold forming, weld-
the surface of the ring while the current is flowing. Examine
ing, grinding, straightening, machining, and proof loading.
the ring within 1 min after current application under a visible
Unless otherwise approved by the contracting agency or as
light of not less than 100 fc (1000 lx). The number of hole
approved in 6.1.3, production parts shall be magnetic particle
indications shall meet or exceed those specifie
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