Meaning and purpose
5.1 The thickness of the coating is usually of great importance to its performance. For most nonferrous metal coating on the steel, magnetic method for nondestructive measurement of coating thickness is reliable, suitable for specification acceptance testing and SPC/SQC application.

5.2 this test method is not applied to determine the thickness of electrodeposited nickel coating on steel. Test method B530 is suitable for this determination.

ASTM B499-2021 “Test Method for Measuring the Thickness of Unmagnetized Coatings on Magnetic Base Metal Materials by Magnetization”

The scope of
1.1 the test methods include the use of magnetic equipment for black metal or other non-magnetic coating thickness on the magnetic base metal nondestructive measurement. It is intended to complement the manufacturer’s instructions for the operation of the instruments and is not intended to replace them.

Note 1: contains more than 8% phosphorus autocatalytic deposition ni-p alloy with sufficient non-magnetic, as long as the measured before any heat treatment, can use this kind of test methods for measuring.

1.2 these instruments measure the magnets and magnetic attraction between parent metal, affected by the presence of coating (classified as “magnetic pull off”), or the change of the magnetic flux density inside probe (classified as “electronic”). These instruments cannot distinguish the thickness of individual layers. They can only measure the probe the cumulative thickness, and all layers below until the base metal.

ASTM B499-2021 “Test Method for Measuring the Thickness of Unmagnetized Coatings on Magnetic Base Metal Materials by Magnetization”

1.3 Measurements made according to this test method will comply with the requirements of ISO International Standard 2178.

1.4 units – to SI units shall be deemed to be standard. The values given in the brackets are for reference only.

1.5 This standard is not intended to address all safety issues, 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 to determine the applicability of regulatory restrictions prior to use.

1.6 this international standard is the technical barriers to trade, according to the world trade organization committee issued “about setting international standards, guidelines and recommendations of the decision of the principle of” the establishment of the internationally recognized principles of standardization.