ASTM A966/A966M-07
(Test Method)Standard Practice for Magnetic Particle Examination of Steel Forgings Using Alternating Current
Standard Practice for Magnetic Particle Examination of Steel Forgings Using Alternating Current
SCOPE
1.1 This practice covers a procedure for the magnetic particle examination of steel forgings using alternating current as the power source. The procedure will produce consistent results upon which acceptance standards can be based. This practice does not contain acceptance limits or recommended quality levels.
1.2 Only alternating 50-60 cycle current shall be used as the electric power source for any of the magnetizing methods. The ability to detect subsurface discontinuities is very limited when using an alternating power source, and therefore the test surfaces should be in the final thermally treated and finish machined condition.
1.3 When subsurface indications are sought in forgings, then dc magnetization in accordance with Test Method A 275/A 275M should be used.
1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. Unless the order specifies the applicable "M" specification designation [SI units], the inch-pound units shall be used.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:A 966/A 966M–07
Standard Practice for
Magnetic Particle Examination of Steel Forgings Using
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Alternating Current
This standard is issued under the fixed designationA966/A966M; 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.
1. Scope* A 275/A 275M Test Method for Magnetic Particle Exami-
nation of Steel Forgings
1.1 This practice covers a procedure for the magnetic
2.2 Other Document:
particle examination of steel forgings using alternating current
Practice No. SNT-TC-1A, Supplement B—Magnetic Par-
as the power source. The procedure will produce consistent
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ticle Method
results upon which acceptance standards can be based. This
practice does not contain acceptance limits or recommended
3. Terminology
quality levels.
3.1 Definitions:
1.2 Onlyalternating50–60cyclecurrentshallbeusedasthe
3.1.1 (ac) magnetic particle method of examination, n—a
electric power source for any of the magnetizing methods. The
method for detecting discontinuities on the surface in suitably
ability to detect subsurface discontinuities is very limited when
magnetized materials, which employs finely divided magnetic
using an alternating power source, and therefore the test
particles that tend to congregate in regions of leakage fields.
surfaces should be in the final thermally treated and finish
3.1.2 indication, n—the visual magnetic particle buildup
machined condition.
resulting from leakage fields in the magnetic field.
1.3 When subsurface indications are sought in forgings,
3.1.3 linear indication, n—an indication in which the length
then dc magnetization in accordance with Test Method A 275/
is at least three times the width. The minimum length of
A 275M should be used.
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indications to be considered linear shall be ⁄16 in. [1.5 mm].
1.4 The values stated in either inch-pound units or SI units
3.1.4 magnetic flux, n—the product of the magnetic induc-
are to be regarded separately as standard. Within the text, the
tion and the area of a surface (or cross section) when the
SI units are shown in brackets. The values stated in each
magnetic induction is uniformly distributed and normal to the
system are not exact equivalents; therefore each system shall
plane of the surface.
be used independently of the other. Combining values from the
3.1.4.1 Discussion—The concept that the magnetic field is
two systems may result in nonconformance with the specifi-
flowing along the lines of force suggests that these lines are
cation. Unless the order specifies the applicable “M” specifi-
therefore “flux” lines, and they are called magnetic flux.
cation designation [SI units], the inch-pound units shall be
3.1.5 nonrelevant indications, n—indications produced by
used.
leakagefieldswheretheconditionscausingthemarepresentby
1.5 This standard does not purport to address all of the
accident or part design, or other features of the part having no
safety concerns, if any, associated with its use. It is the
relation to the damaging flaws being sought.
responsibility of the user of this standard to establish appro-
3.1.5.1 Discussion—This term signifies that such an indica-
priate safety and health practices and determine the applica-
tion has no relation to the discontinuities that might constitute
bility of regulatory limitations prior to use.
defects.
2. Referenced Documents
4. Basis ofApplication
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2.1 ASTM Standards:
4.1 When in accordance with the requirements of the
inquiry, contract, order, or specifications, forgings are to be
examined by the magnetic particle method using alternating
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This practice is under the jurisdiction of ASTM Committee A01 on Steel,
current; the manufacturer and the supplier shall be in agree-
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
ment concerning the following:
A01.06 on Steel Forgings and Billets.
Current edition approved May 1, 2007. Published June 2007. Originally 4.1.1 The locations on the forging that are to be subjected to
approved in 1996. Last previous edition approved in 2006 as A 966/A 966M – 96
magnetic particle examination.
(2006).
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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Standards volume information, refer to the standard’s Document Summary page on Available from American Society for NonDestructive Testing, 1711 Arlingate
the ASTM website. Lane, P.O. Box 28518, Columbus, OH 43228-0518.
*ASummary of Changes section appears at the end of this standard.
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