ASTM International

Standard Specification for Carbon and Alloy Steel Compressible-Washer-Type Direct Tension Indicators for Use with Cap Screws, Bolts, Anchors, and Studs
 N F2437

Annotation

This specification covers the requirements for carbon and alloy steel compressible-washer-type direct tension indicators capable of indicating a specified bolt tension in cap screws, bolts, anchors, and studs.

Direct tension indicators in nominal diameter sizes ? through 2? in. are covered.

There are two Types of DTIs covered by this specification, Type 1 and Type 2.

Type 1 DTIs are suitable for comparatively large bearing surfaces. Type 1 DTIs are available in Grades 55 and 105, which differ in the amount of tension they indicate at a prescribed gap (see Table 1).

NOTE 1—Examples of a comparatively large bearing surface would include heavy hex bolts, heavy hex nuts, and so forth.

Type 2 DTIs are suitable for comparatively smaller bearing surfaces.Type 2 DTIs are available in Grades 5 and 8, which differ in the amount of tension they indicate at a prescribed gap (see Table 1).

NOTE 2—Examples of a comparatively small bearing surface would include a hex cap screw, hex nut, and so forth.

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.

The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

The following precautionary statement pertains only to the test method portions, Section 12 and Appendix XI 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.