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    ASTM B499 - 09(2021)e1

    Standard Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic Basis Metals

    Active Standard ASTM B499 | Developed by Subcommittee: B08.10

    Book of Standards Volume: 02.05


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    Significance and Use

    5.1 The thickness of a coating is often critical to its performance. For most nonferrous coatings on steel, the magnetic method is reliable for measuring coating thickness nondestructively and is suitable for specification acceptance testing and SPC/SQC applications.

    5.2 This test method should not be used to determine the thickness of electrodeposited nickel coatings on steel. Test Method B530 is suitable for that determination.

    1. Scope

    1.1 This test method covers the use of magnetic instruments for the nondestructive measurement of the thickness of nonmagnetic coatings over ferrous or other magnetic base metals. It is intended to supplement manufacturers’ instructions for the operation of the instruments and is not intended to replace them.

    Note 1: Autocatalytically deposited nickel-phosphorus alloys containing more than 8 % phosphorus are sufficiently nonmagnetic to be measured by this test method, as long as the measurement is made prior to any heat treatment.

    1.2 These instruments measure either the magnetic attraction between a magnet and the basis metal, as influenced by the presence of the coating (categorized as “magnetic pull-off”), or the change in magnetic-flux density within the probe (categorized as “electronic”). These instruments cannot distinguish the thickness of individual layers. They can only measure the cumulative thickness of all layers beneath the probe down to the base metal.

    1.3 Measurements made in accordance with this test method will be in compliance with the requirements of ISO International Standard 2178.

    1.4 Units—The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

    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.

    International Standard

    ISO 2178 Non-Magnetic Coatings on Magnetic SubstrateMeasurement of Coating ThicknessMagnetic Method Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.

    ASTM Standards

    B530 Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Electrodeposited Nickel Coatings on Magnetic and Nonmagnetic Substrates


    ICS Code

    ICS Number Code 17.040.20 (Properties of surfaces)

    UNSPSC Code

    UNSPSC Code


    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/B0499-09R21E01

    Citation Format

    ASTM B499-09(2021)e1, Standard Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic Basis Metals, ASTM International, West Conshohocken, PA, 2021, www.astm.org

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