1.1 本规程涵盖了使用磁性和涡流式测厚仪（量规）对金属（即导电）基材上的涂层进行无损测厚。基材可以是黑色或有色金属。被测量的涂层或镀层可以是导电或绝缘的，也可以是黑色或非黑色的。 1.2 实践中涵盖了这些工具的更具体用途 D7091 以及ASTM发布的以下试验方法:试验方法 B244页 , B499页 和 B530 . 1.3 单位- 以国际单位制表示的数值应视为标准值。 括号中给出的值是英寸-磅单位的数学转换，仅供参考，不被视为标准值。 1.4 根据本规程进行的测量将符合ISO的要求 2178，1982年印刷。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 概述- 大多数测厚仪不适用于涂层基材厚度和材料的所有组合。特定仪器的限制通常由其制造商描述。在选择要使用的仪器和所需的测量精度之前，应审查待测量的基材和涂层组合以及基材和涂层的固有变化。 4.2 磁性- 磁性仪表测量磁铁与涂层或其基材之间的磁力，或穿过涂层和基材的磁通量路径的磁阻。 这些仪表设计用于测量磁性基底上非磁性涂层的厚度。其中一些还将测量磁性或非磁性基底上镍涂层的厚度。 6. 4.3 涡流- 涡流式测厚仪是测量由涂层厚度变化引起的涡流感应线圈阻抗变化的电子仪器。只有当涂层的导电性与基材的导电性显著不同时，才能使用它们。 4.4 准确性- 测量精度取决于仪器、箔、其校准和标准化以及其操作条件。 精度还受到第节中列出的干扰的影响 5. ，例如零件几何形状（曲率）、磁导率、电导率和表面粗糙度。 注2: 理想条件下的这种做法可以使涂层厚度在±10范围内确定 % 或在±2.5μm（或±0.0001）范围内 英寸），以较大者为准。（参见 附录X2 .)

1.1 This practice covers the use of magnetic- and eddy current-type thickness instruments (gauges) for nondestructive thickness measurement of a coating on a metal (that is, electrically conducting) substrate. The substrate may be ferrous or nonferrous. The coating or plating being measured may be electrically conducting or insulating as well as ferrous or non-ferrous. 1.2 More specific uses of these instruments are covered by Practice D7091 and the following test methods issued by ASTM: Test Methods B244 , B499 , and B530 . 1.3 Units— The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard. 1.4 Measurements made in accordance with this practice will be in compliance with the requirements of ISO 2178 as printed in 1982. 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. ====== Significance And Use ====== 4.1 General— Most thickness gauges are not applicable to all combinations of coating-substrate thicknesses and materials. The limitations of a particular instrument are generally delineated by its manufacturer. The substrate material and coating combination to be measured as well as the inherent variations in the substrate and coating shall be reviewed prior to selecting the instrument to be used and the measurement accuracy required. 4.2 Magnetic— Magnetic-type gauges measure either magnetic attraction between a magnet and a coating or its substrate, or reluctance of a magnetic flux path passing through the coating and substrate. These gauges are designed to measure thickness of a nonmagnetic coating on a magnetic substrate. Some of them will also measure thickness of nickel coatings on a magnetic or nonmagnetic substrate. 6 4.3 Eddy Current— Eddy current-type thickness gauges are electronic instruments that measure variations in impedance of an eddy current inducing coil caused by coating thickness variations. They can only be used if the electrical conductivity of the coating differs significantly from that of the substrate. 4.4 Accuracy— The accuracy of a measurement depends on the instrument, the foils, its calibration and standardization, and its operating conditions. The accuracy is also affected by the interferences listed in Section 5 , such as part geometry (curvature), magnetic permeability, electrical conductivity, and surface roughness. Note 2: This practice under ideal conditions may allow the coating thickness to be determined within ±10 % of its true thickness or to within ±2.5 μm (or ±0.0001 in.), whichever is the greater. (See exceptions in Appendix X2 .)