1、Designation:B49909(Reapproved 2014)Endorsed by AmericanElectroplaters SocietyEndorsed by NationalAssociation of Metal FinishersStandard Test Method forMeasurement of Coating Thicknesses by the MagneticMethod:Nonmagnetic Coatings on Magnetic Basis Metals1This standard is issued under the fixed design
2、ation B499;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reappro
3、val.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the use of magnetic instrumentsfor the nondestructive measurement of the thickness of non-magnetic coatings over ferrous or other magnetic base metals.It is intended to supplem
4、ent manufacturersinstructions for theoperation of the instruments and is not intended to replacethem.NOTE1Autocatalytically deposited nickel-phosphorus alloys contain-ing more than 8%phosphorus are sufficiently nonmagnetic to bemeasured by this test method,as long as the measurement is made priorto
5、any heat treatment.1.2 These instruments measure either the magnetic attrac-tion between a magnet and the basis metal,as influenced by thepresence of the coating(categorized as“magnetic pull-off”),orthe change in magnetic-flux density within the probe(catego-rized as“electronic”).These instruments c
6、annot distinguish thethickness of individual layers.They can only measure thecumulative thickness of all layers beneath the probe down tothe base metal.1.3 Measurements made in accordance with this test methodwill be in compliance with the requirements of ISO Interna-tional Standard 2178 as printed
7、in 1982.1.4 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish
8、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B530 Test Method for Measurement of Coating Thicknessesby the Magnetic Method:Electrodeposited Nickel Coat-ings on Magnetic and Nonmagnetic Subs
9、trates2.2 International Standard:ISO 2178 Non-Magnetic Coatings on Magnetic SubstrateMeasurement of Coating ThicknessMagnetic Method33.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 accuracy,nthe measure of the magnitude of errorbetween the result of a measurement and the true t
10、hickness ofthe item being measured.3.1.2 adjustment,nthe physical act of aligning a instru-ments thickness readings to match those of a known thicknesssample(removal of bias),in order to improve the accuracy ofthe instrument on a specific surface or within a specific portionof its measurement range.
11、An adjustment will affect theoutcome of subsequent readings.3.1.3 calibration,nthe high-level,controlled and docu-mented process of obtaining measurements on traceable cali-bration standards over the full operating range of theinstrument,then making the necessary instrument adjustments(as required)t
12、o correct any out-of-tolerance conditions.3.1.3.1 DiscussionCalibration of coating thickness instru-ments is performed by the equipment manufacturer,an autho-rized agent,or by an authorized,trained calibration laboratoryin a controlled environment using a documented process.Theoutcome of the calibra
13、tion process is to restore/realign theinstrument to meet/exceed the manufacturers stated accuracy.1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 onTest Methods.Current edition approved May 1,2
14、014.Published May 2014.Originallyapproved in 1969.Last previous edition approved in 2009 as B499 09.DOI:10.1520/B0499-09R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer
15、to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.4 refer
16、ence standard,na specimen of known thicknessused to verify the accuracy of a coating thickness measuringinstrument.3.1.5 verification of accuracy,nobtaining measurementson a reference standard prior to instrument use for the purposeof determining the ability of the coating thickness instrument toproduce reliable values,compared to the combined instrumentmanufacturers stated accuracy and the stated accuracy of thereference standard.4.Summary of Test Method4.1 Magnetic pull-off instruments employ
