1.1 本规范涵盖了碳钢和合金钢可压缩垫圈型直接张力指示器（DTI）的要求，该指示器能够指示有头螺钉、螺栓、锚固件和螺柱中的特定螺栓张力。 1.2 英寸尺寸的直接张力指示器 1. / 4. 到2 1. / 2. 在里面包括公制尺寸M6和M72。 1.3 对于英制紧固件，直接张力指示器有两种类型和四个等级，即5、8、55和105级，对于公制紧固件，有两个性能等级，即8.8和10.9级，每个等级在给定间隙下的压缩载荷要求不同（见 表1 和 表2 ). 1.3.1 类型1 DTI适用于相对较小的轴承表面。样式1 DTI可用于5级和8级，它们在规定间隙处指示的张力量不同（参见 表1 和 表3 ). 1.3.2 类型2 DTI适用于较大的支承面。样式2 DTI可用于55级和105级，它们在规定间隙处指示的张力量不同（参见 表1 和 表3 ). （A） 压缩载荷要求确定了直接张力指示器的能力，以满足这些等级的典型张力要求。用户没有义务根据这些张力安装紧固件和DTI，并且可以自由指定安装到较低的张力值。如有规定，DTI供应商应根据 15.2 使用户能够为应用的预期目标张力选择适当的间隙标准。 （B） 标称尺寸为5级和8级的平均压缩载荷值达到1- 1. / 2. in基于SAE J429带帽螺钉验证载荷的75%。标称尺寸大于1的5级- 1. / 2. 最多2个- 1. / 2. 包括在内，平均压缩载荷值基于ASTM A449验证载荷的75%。标称尺寸大于1的8级- 1. / 2. 最多2个- 1. / 2. 包括在内，平均压缩载荷值基于ASTM A354BD验证载荷的75%。 （C） 55级和105级的平均压缩载荷值基于60 % 所用匹配紧固件的屈服强度。 （A） 性能等级8.8和10.9的平均压缩载荷值基于ISO 898验证载荷的75%- 1螺栓/螺柱/螺钉。 （A） 英制螺栓和带帽螺钉尺寸在ASME B18.2.1中指定，公制螺栓尺寸在ISO 4014中指定。 （B） 英制螺母尺寸在ASME B18.2.2中指定，公制螺母尺寸在ISO 4032中指定。 1.4 直接张力指示器用于安装在螺栓或有头螺钉头、六角螺母下，或紧靠硬化垫圈或其他平面硬化表面。 1.5 推荐的紧固件- 符合中引用标准要求的紧固件 表3 被视为与所列DTI等级或类别兼容。 1.6 英寸DTI的值用英寸-磅单位表示，公制DTI的值用国际单位制表示。以国际单位制或英寸表示的数值- 磅单位应单独视为标准单位。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.7 以下预防说明仅适用于试验方法部分，第 12 本标准无意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。 1.8 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 specification covers the requirements for carbon and alloy steel compressible-washer-type direct tension indicators (DTIs) capable of indicating a specified bolt tension in cap screws, bolts, anchors, and studs. 1.2 Direct tension indicators in inch sizes 1 / 4 through 2 1 / 2 in. and metric sizes M6 and M72 are covered. 1.3 Direct tension indicators have two styles and four grades for inch fasteners, Grades 5, 8, 55, and 105, and two property classes for metric fasteners, property classes 8.8 and 10.9 each of which differ in their compressive load requirements at a given gap (see Table 1 and Table 2 ). 1.3.1 Style 1 DTIs are suitable for comparatively smaller bearing surfaces. Style 1 DTIs are available in Grades 5 and 8, which differ in the amount of tension they indicate at a prescribed gap (see Table 1 and Table 3 ). 1.3.2 Style 2 DTIs are suitable for comparatively large bearing surfaces. Style 2 DTIs are available in Grades 55 and 105, which differ in the amount of tension they indicate at a prescribed gap (see Table 1 and Table 3 ). (A) Compression load requirements establish the capability of the direct tension indicators to satisfy typical tension requirements for these grades. The user is not obliged to install fasteners and DTIs to these tensions, and is free to specify installation to lower tension values. When so specified, the DTI supplier shall provide a load-gap curve in accordance with 15.2 to enable the user to select the appropriate gap criteria for the intended target tension of the application. (B) The Mean compression load values for Grades 5 and 8 in nominal sizes up through 1- 1 / 2 in are based upon 75% of the proof load for SAE J429 cap screws. For Grade 5 in nominal sizes over 1- 1 / 2 in and up to 2- 1 / 2 in inclusive, the mean compression load values are based on 75% of the proof load for ASTM A449. For grade 8 in nominal sizes over 1- 1 / 2 in and up to 2- 1 / 2 in inclusive, mean compression load values are based upon 75 % of the proof load for ASTM A354BD. (C) Mean compression load values for Grades 55 and 105 are based upon 60 % of the yield strength for the matching fasteners on which they are used. (A) The Mean compression load values for property classes 8.8 and 10.9 are based upon 75% of the proof load for ISO 898-1 Bolts/Stud/Screws. (A) A Inch bolt and cap screw dimensions are designated in ASME B18.2.1 and metric bolt dimensions are designated in ISO 4014. (B) Inch nuts dimensions are designated in ASME B18.2.2 and metric nut dimensions are designated in ISO 4032. 1.4 Direct tension indicators are intended for installation under a bolt or cap screw head, a hex nut, or against a hardened washer or other flat hardened surface. 1.5 Recommended Fasteners— Fasteners meeting the requirements of the standards referenced in Table 3 are considered compatible with the DTI grade or class listed. 1.6 The values stated for Inch DTIs are expressed in inch-pound units and for Metric DTIs values are expressed in SI units.The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.7 The following precautionary statement pertains only to the test method portions, Section 12 of this specification: 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. 1.8 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.