本文件适用于尺寸不超过500mm的内径千分尺，最大测量范围为25mm，刻度间隔和分辨率分别为0,01mm。它规定了内部零件最重要的尺寸、功能和质量特征 测微计及其测试。

The document applies to internal micrometers for dimensions up to 500 mm, with a maximal measuring range of 25 mm and a scale interval and a resolution of 0,01mm respectively. It specifies the most important dimensional, functional and quality characteristics of internal micrometers and their testing.