1.1 本试验方法涵盖通过测量测试热电偶的电动势与参考热电偶（之前称为二级标准）的电动势之间的差异来确定热电偶相对于NIST铂67（Pt-67）的热电动势的试验，参考热电偶的电动势与NIST铂67具有已知关系。 1.2 本试验适用于在通常与热电偶及其延长线相关的温度范围内的新热电偶材料。规范中受保护热电偶的建议温度上限表 E230 列出了与字母指定的热电偶类型相关的范围。 ASTM MNL-12 2. 列出了扩展电路材料的温度范围。 1.3 本试验不适用于稳定性试验或不均匀性试验。 1.4 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 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和健康实践，并确定监管限制的适用性。 ====意义和用途====== 5.1 该测试方法旨在在一个或多个测试温度下校准热电偶。获得的数据有时被称为emf的初始值，因为在测试温度下的时间有限。 5.2 该测试方法主要用于热电材料线轴或线圈或带材的供应商。通常一次测试一个以上的样本，单个热电偶的合成EMF用于匹配用作热电偶或延伸接线的配对热电偶。 5.3 使用本试验方法测试的由两个不同热电偶组成的热电偶的电动势可通过在特定温度下从正极热电偶的电动势中代数减去负极热电偶的电动势来确定。热电偶的电动势也可以通过试验方法中所述的试验来确定 E220 ，但试验方法 E220 不考虑单个热电偶相对于Pt-67的电动势值。 5.4 该试验方法通常用于热电偶材料在生产或分销过程中的校准，而不是用于准确测定所用热电偶的性能。如果测试样品以前使用过，测试结果可能不会反映与热电偶在使用时相同的电动势。 例如，由于使用过程中的化学或冶金反应，导线中可能会产生不均匀性。由于电动势是在热梯度中产生的，并且在测试条件下沿导线的温度分布不太可能与使用时相同，因此测试结果可能会产生误导。 5.5 测试结果适用于规范验收、制造控制、设计或研发目的。

1.1 This test method covers a test for determining the thermoelectric emf of a thermoelement versus NIST platinum 67 (Pt-67) by means of measuring the difference between the emf of the test thermoelement and the emf of a reference thermoelement (previously referred to as a secondary standard), which has a known relationship to NIST Pt-67. 1.2 This test is applicable to new thermocouple materials over the temperature ranges normally associated with thermocouples and their extension wires. The table on Suggested Upper Temperature Limits for Protected Thermocouples in Specification E230 lists the ranges associated with the letter-designated types of thermocouples. ASTM MNL-12 2 lists the temperature range of extension circuit materials. 1.3 This test is not applicable to stability testing or inhomogeneity testing. 1.4 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 5.1 This test method is designed to calibrate a thermoelement at one or more test temperatures. The data obtained are sometimes referred to as initial values of emf because the time at the test temperature is limited. 5.2 This test method is employed mainly by providers of spools or coils of wire or strips of thermoelectric material. Generally more than one specimen at a time is tested, and the resultant emfs of individual thermoelements are used to match to companion thermoelements for use as thermocouples or in extension wiring. 5.3 The emf of a thermocouple comprised of two different thermoelements as tested with this test method may be determined by algebraically subtracting the emf of the negative thermoelement from the emf of the positive thermoelement at a particular temperature. The emf of a thermocouple may also be determined by the test described in Test Method E220 , but Test Method E220 does not take into account the values of the emf of the individual thermoelements relative to Pt-67. 5.4 This test method is normally used for the calibration of thermocouple materials during their production or distribution, not for the accurate determination of the properties of a used thermocouple. If the test samples were subjected to previous use, the test results may not reflect the same emf as the thermocouple did while in service. For example, inhomogeneities may have been induced in the wires because of a chemical or metallurgical reaction while in service. Since emf is developed in the thermal gradient, and it is unlikely that the temperature profile along the wire under testing conditions will be the same as it was while in service, the test results may be misleading. 5.5 The test results are suitable for specification acceptance, manufacturing control, design, or research and development purposes.