ASTM A966 / A966M - 15(2020)

    Standard Practice for Magnetic Particle Examination of Steel Forgings Using Alternating Current

    Active Standard ASTM A966 / A966M | Developed by Subcommittee: A01.06

    Book of Standards Volume: 01.05


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    Significance and Use

    5.1 For ferromagnetic materials, magnetic particle examination is widely specified for the detection of surface and near-surface flaws such as cracks, laps, seams, and linearly oriented nonmetallic inclusions. Such examinations are included as mandatory requirements in some forging standards such as Specifications A508/A508M and A963/A963M.

    5.2 Use of alternating current as the power source for magnetic particle examination imposes a significant restriction on the detection of subsurface indications, so that the procedure is essentially limited to the finding of flaws that are open to the surface. Attention therefore is drawn to the need to have the component in the finish-machined condition before conducting the magnetic particle examination.

    5.3 The presence of residual magnetic fields in a component may be undesirable, and an advantage of the use of an ac power source for magnetic particle examination is that an acceptable level of demagnetization can be readily achieved.

    1. 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.

    1.3 When subsurface indications are sought in forgings, then dc magnetization in accordance with Practice A275/A275M 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 necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. Unless the order specifies the applicable “M” specification designation [SI units], the inch-pound units shall be used.

    1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

    1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    A275/A275M Practice for Magnetic Particle Examination of Steel Forgings

    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

    A963/A963M Specification for Deep Drawing Steel (DDS), Sheet, Carbon, Cold-Rolled


    ICS Code

    ICS Number Code 77.040.20 (Non-destructive testing of metals)

    UNSPSC Code

    UNSPSC Code 31132100(Steel forgings)


    Referencing This Standard
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    DOI: 10.1520/A0966_A0966M-15R20

    Citation Format

    ASTM A966 / A966M-15(2020), Standard Practice for Magnetic Particle Examination of Steel Forgings Using Alternating Current, ASTM International, West Conshohocken, PA, 2020, www.astm.org

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