1.1这些试验方法包括测定金属材料的洛氏硬度和洛氏表面硬度，包括洛氏硬度试验机器验证的试验方法（B部分）和标准硬度试块的校准（C部分）。 1.2以英寸-磅为单位的数值应视为标准值。国际单位制仅供参考。 1.3 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。 （见注释6。） 注1:美国国家标准与技术研究所（NIST）维持美国的国家洛氏硬度标准。1998年6月，NIST发布了新的罗克韦尔C标度（HRC）试块作为标准参考材料。使用NIST的主要参考标准机校准试块。 NIST标准的主要优点是其HRC水平与世界其他工业化国家一致。NIST HRC水平确定的材料硬度略高于美国过去75年使用的历史标准。E 18修订版要求，洛氏硬度压头和硬度计的所有性能验证必须使用可追溯至NIST维持的洛氏标准的校准试块。 这可以通过使用可追溯到NIST标准的校准商用试块或直接使用NIST SRM来实现。该要求仅适用于NIST提供主要参考试块的罗克韦尔标尺。 注2-在本标准的早期版本中，球压头要求为硬钢。从本版本开始，也允许使用碳化钨球。这一变化是计划中的未来过渡的第一步，以消除钢球，只允许使用碳化钨球。 钢球压头的消除计划在大约两年内进行。使用碳化钨球将改善洛氏硬度试验，因为钢球在使用过程中会变平，从而导致硬度值错误升高。此外，NIST计划使用碳化钨球对HRB规模进行标准化。由于这一变化，本版本还要求，当使用球压头时，洛氏硬度值必须报告，标度名称后接字母“S”表示使用钢球，或字母“W”表示使用碳化钨球。 用户需要注意的是，洛氏硬度测试对比了钢球和碳化钨球的使用，结果不同。例如，根据被测材料及其硬度水平，使用碳化钨球压头的洛氏B标尺试验得出的结果比使用钢球压头时低一个洛氏点。

1.1 These test methods cover the determination of the Rockwell hardness and the Rockwell superficial hardness of metallic materials, including test methods for the verification of machines for Rockwell hardness testing (Part B) and the calibration of standardized hardness test blocks (Part C). 1.2 Values stated in inch-pound units are to be regarded as the standard. SI units are provided for information only. 1.3 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. (See Note 6.) Note 1—The National Institute of Standards and Technology (NIST) maintains the national Rockwell hardness standards for the United States. In June 1998, NIST released new Rockwell C scale (HRC) test blocks as Standard Reference Materials (SRMs). The blocks were calibrated using NIST's primary reference standardizing machine. The major benefit of the NIST standards is that their HRC levels are in line with the other industrialized countries around the world. The NIST HRC levels establish the hardness of materials slightly harder than the historical standards used in the United States for the past 75 years. The revision of E 18 requires that all performance verifications of Rockwell hardness indenters and hardness machines must be made using test blocks calibrated traceable to the Rockwell standards maintained by NIST. This can be accomplished through the use of commercial test blocks calibrated traceable to the NIST standards or by directly using the NIST SRMs. This requirement will apply only to the Rockwell scale(s) for which NIST supplies primary reference test blocks. Note 2—In previous editions of this standard, ball indenters were required to be of hard steel. Beginning with this edition, tungsten-carbide balls are also allowed. This change is a first step in a planned future transition to eliminate steel balls and allow only the use of tungsten carbide balls. The elimination of steel ball indenters is scheduled to occur in about two years. The use of tungsten carbide balls will provide an improvement to the Rockwell hardness test because of the tendency of steel balls to flatten with use, which results in an erroneously elevated hardness value. In addition, NIST is planning to standardize the HRB scale using tungsten-carbide balls. As a result of this change, this edition also requires that when a ball indenter is used, the Rockwell hardness value must be reported with the scale designation followed by the letter "S" to indicate the use of a steel ball or the letter "W" to indicate the use of a tungsten carbide ball. The user is cautioned that Rockwell hardness tests comparing the use of steel and tungsten carbide balls have been shown to give different results. For example, depending on the material tested and its hardness level, Rockwell B scale tests using a tungsten carbide ball indenter have given results up to one Rockwell point lower than when a steel ball indenter is used.