ISO 4545-1:2017规定了金属材料在0009 807 N至19613 N试验力下的努氏硬度试验方法。 本文件规定了压痕对角线长度的努氏硬度试验≥0020毫米。由于光学测量的局限性和尖端几何形状的缺陷，使用这种方法从较小的压痕中确定努氏硬度超出了本文的范围，因为结果将受到很大的不确定性。ISO 14577-1允许从较小的压痕中测定硬度。 规定了一种定期验证方法，用于用户对使用中的试验机进行例行检查。 金属涂层努氏试验的特殊注意事项见ISO 4516。

ISO 4545-1:2017 specifies the Knoop hardness test method for metallic materials for test forces from 0,009 807 N to 19,613 N. The Knoop hardness test is specified in this document for lengths of indentation diagonals ≥0,020 mm. Using this method to determine Knoop hardness from smaller indentations is outside the scope of this document as results would suffer from large uncertainties due to the limitations of optical measurement and imperfections in tip geometry. ISO 14577-1 allows the determination of hardness from smaller indentations. A periodic verification method is specified for routine checking of the testing machine in service by the user. Special considerations for Knoop testing of metallic coatings can be found in ISO 4516.