ASTM A275/A275M-15
(Practice)Standard Practice for Magnetic Particle Examination of Steel Forgings
Standard Practice for Magnetic Particle Examination of Steel Forgings
ABSTRACT
This test method covers the procedures for the standard practice of performing magnetic particle examination on steel forgings. The inspection medium shall consist of finely divided ferromagnetic particles, whose size, shape and magnetic properties, both individually and collectively, shall be taken into account. Forgings may be magnetized in the longitudinal or circular direction by employing the surge or continuous current flow methods. Magnetization may be applied by passing current through the piece or by inducing a magnetic field by means of a central conductor, such as a prod or yoke, or by coils. While the material is properly magnetized, the magnetic particles may be applied by either the dry method, wet method, or fluorescent method. The parts shall also be sufficiently demagnetized after inspection so that residual or leakage fields will not interfere with future operations to which the steel forgings shall be used for. Indications to be evaluated are grouped into three broad classes, namely: surface defects, which include laminar defects, forging laps and folds, flakes (thermal ruptures caused by entrapped hydrogen), heat-treating cracks, shrinkage cracks, grinding cracks, and etching or plating cracks; subsurface defects, which include stringers of nonmetallic inclusions, large nonmetallics, cracks in underbeads of welds, and forging bursts; and nonrelevant or false indications, which include magnetic writing, changes in section, edge of weld, and flow lines.
SIGNIFICANCE AND USE
4.1 For ferromagnetic materials, magnetic particle examination is widely specified for the detection of surface and near surface discontinuities such as cracks, laps, seams, and linearly oriented nonmetallic inclusions. Such examinations are included as mandatory requirements in some forging standards such as Specification A508/A508M.
4.2 Use of direct current or rectified alternating (full or half wave) current as the power source for magnetic particle examination allows detection of subsurface discontinuities.
SCOPE
1.1 This practice2 covers a procedure for magnetic particle examination of steel forgings. The procedure will produce consistent results upon which acceptance standards can be based. This practice does not contain acceptance standards or recommended quality levels.
1.2 Only direct current or rectified alternating (full or half wave) current shall be used as the electric power source for any of the magnetizing methods. Alternating current is not permitted because its capability to detect subsurface discontinuities is very limited and therefore unsuitable.
1.2.1 Portable battery powered electromagnetic yokes are outside the scope of this practice.
Note 1: Guide E709 may be utilized for magnetic particle examination in the field for machinery components originally manufactured from steel forgings.
1.3 The minimum requirements for magnetic particle examination shall conform to practice standards of Practice E1444/E1444M. If the requirements of this practice are in conflict with the requirements of Practice E1444/E1444M, the requirements of this practice shall prevail.
1.4 This practice and the applicable material specifications are expressed in both inch-pound units and SI units. However, unless the order specifies the applicable “M” specification designation [SI units], the material shall be furnished to inch-pound units.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.6 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...
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Designation: A275/A275M − 15
Standard Practice for
1
Magnetic Particle Examination of Steel Forgings
This standard is issued under the fixed designationA275/A275M; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
2
1.1 This practice covers a procedure for magnetic particle
responsibility of the user of this standard to establish appro-
examination of steel forgings. The procedure will produce
priate safety and health practices and determine the applica-
consistent results upon which acceptance standards can be
bility of regulatory limitations prior to use.
based. This practice does not contain acceptance standards or
recommended quality levels.
2. Referenced Documents
1.2 Only direct current or rectified alternating (full or half
3
2.1 ASTM Standards:
wave)currentshallbeusedastheelectricpowersourceforany
A508/A508M Specification for Quenched and Tempered
of the magnetizing methods.Alternating current is not permit-
Vacuum-Treated Carbon and Alloy Steel Forgings for
ted because its capability to detect subsurface discontinuities is
Pressure Vessels
very limited and therefore unsuitable.
A788/A788M Specification for Steel Forgings, General Re-
1.2.1 Portable battery powered electromagnetic yokes are
quirements
outside the scope of this practice.
E709 Guide for Magnetic Particle Testing
NOTE1—GuideE709maybeutilizedformagneticparticleexamination E1444/E1444M Practice for Magnetic Particle Testing
in the field for machinery components originally manufactured from steel
2.2 Other Document:
forgings.
Recommended Practice No. SNT-TC-1A, Supplement
4
1.3 The minimum requirements for magnetic particle ex-
B-Magnetic Particle Method
amination shall conform to practice standards of Practice
E1444/E1444M. If the requirements of this practice are in
3. Terminology
conflict with the requirements of Practice E1444/E1444M, the
3.1 Definitions:
requirements of this practice shall prevail.
3.1.1 indication—the visual magnetic particle buildup re-
1.4 This practice and the applicable material specifications
sulting from leakage fields in the magnetic field.
are expressed in both inch-pound units and SI units. However,
3.1.2 linear indication—an indication in which the length is
unless the order specifies the applicable “M” specification
at least three times the width. The minimum length of
designation [SI units], the material shall be furnished to
1
indications to be considered linear shall be ⁄16 in. [1.6 mm].
inch-pound units.
3.1.3 magnetic flux—the product of the magnetic induction
1.5 The values stated in either SI units or inch-pound units
and the area of a surface (or cross section) when the magnetic
are to be regarded separately as standard. The values stated in
induction is uniformly distributed and normal to the plane of
each system may not be exact equivalents; therefore, each
the surface. The concept that the magnetic field is flowing
system shall be used independently of the other. Combining
along the lines of force suggests that these lines are therefore
values from the two systems may result in non-conformance
“flux” lines, and they are called magnetic flux.
with the standard.
3.1.4 magnetic particle method of examination—a method
for detecting discontinuities on or near the surface in suitably
1
This practice is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
3
A01.06 on Steel Forgings and Billets. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2015. Published May 2015. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1944. Last previous edition approved in 2013 as A275/A275M – 08 Standards volume information, refer to the standard’s Document Summary page on
(2013). DOI: 10.1520/A0275_A0275M-15. the ASTM website.
2 4
For ASME Boiler and Pressure Vessel Code applications see related Method AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
SA-275/SA-275M in Section II of that Code. 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
A275/A275M
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A275/A275M − 08 (Reapproved 2013) A275/A275M − 15
Standard Practice for
1
Magnetic Particle Examination of Steel Forgings
This standard is issued under the fixed designation A275/A275M; 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 (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
2
1.1 This practice covers a procedure for magnetic particle examination of steel forgings. The procedure will produce consistent
results upon which acceptance standards can be based. This practice does not contain acceptance standards or recommended
quality levels.
1.2 Only direct current or rectified alternating (full or half wave) current shall be used as the electric power source for any of
the magnetizing methods. Alternating current is not permitted because its capability to detect subsurface discontinuities is very
limited and therefore unsuitable.
1.2.1 Portable battery powered electromagnetic yokes are outside the scope of this practice.
NOTE 1—Guide E709 may be utilized for magnetic particle examination in the field for machinery components originally manufactured from steel
forgings.
1.3 The minimum requirements for magnetic particle examination shall conform to practice standards of Practice E1444/
E1444M. If the requirements of this practice are in conflict with the requirements of Practice E1444/E1444M, the requirements
of this practice shall prevail.
1.4 This practice and the applicable material specifications are expressed in both inch-pound units and SI units. However, unless
the order specifies the applicable “M” specification designation [SI units], the material shall be furnished to inch-pound units.
1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.6 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.
2. Referenced Documents
3
2.1 ASTM Standards:
A508/A508M Specification for Quenched and Tempered Vacuum-Treated Carbon and Alloy Steel Forgings for Pressure Vessels
A788/A788M Specification for Steel Forgings, General Requirements
E709 Guide for Magnetic Particle Testing
E1444/E1444M Practice for Magnetic Particle Testing
2.2 Other Document:
4
Recommended Practice No. SNT-TC-1A, Supplement B-Magnetic Particle Method
3. Terminology
3.1 Definitions:
3.1.1 indication—the visual magnetic particle buildup resulting from leakage fields in the magnetic field.
1
This practice is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.06
on Steel Forgings and Billets.
Current edition approved April 1, 2013May 1, 2015. Published April 2013May 2015. Originally approved in 1944. Last previous edition approved in 20082013 as
A275/A275M – 08.A275/A275M – 08 (2013). DOI: 10.1520/A0275_A0275M-08R13.10.1520/A0275_A0275M-15.
2
For ASME Boiler and Pressure Vessel Code applications see related Method SA-275/SA-275M in Section II of that Code.
3
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
4
Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
A275/A275M − 15
3.1.2 linear indication—an indication in which the length is at least three times the width. The minimum length of indications
1
to be considered linear shall be ⁄16 in. [1.6 mm].
3.1.3 magnetic flux—the product of the magnetic induction
...
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