1.1 该分类涵盖了标准商业等级白云母裂片的测定，并规定了每个等级的最大允许物理缺陷。无论云母的基本颜色或其来源如何，它都适用于商用天然白云母裂片。 1.2 以英寸-磅为单位的数值应视为标准值。括号中给出的值仅供参考。 1.3 本标准与ISO 6386非常相似。预计材料将使用任一标准的标准进行相同分类。中“ASTM等级号”下所示的等级 表1 和 表2 在ISO 6386-1981的“旧等级号”下显示。 1.4 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。

1.1 This classification covers the determination of muscovite mica splittings of standard commercial grades and specifies the maximum allowable physical defects for each grade. It is applicable to commercially available natural muscovite mica splittings regardless of the basic color of the mica or its source. 1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard is very similar to ISO 6386. It is expected that materials would be classified identically using the criteria of either standard. The grades shown under “ASTM Grade No.” in Table 1 and Table 2 are shown under “Old Grade No.” in ISO 6386-1981. 1.4 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.