Abstract
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. These DTIs 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 following are two types of DTIs: Type 1 DTIs are suitable for comparatively large bearing surfaces and Type 2 DTIs are suitable for comparatively smaller bearing surfaces. DTIs shall have a configuration produced by extrusion, punching, pressing, or similar forming to permit a measurable decrease in thickness when placed in compression. The design shall be such that the degree of plastic deformation of the protrusions shall indicate the tension in a tightened cap screw, bolt, anchor, or stud. The process used for heat treatment of DTIs, if required, shall be through-hardening by heating to a temperature above the upper transformation temperature, quenching in oil, and then tempering by reheating to a suitable temperature to attain desired mechanical/performance properties. Protective coatings, platings, or finishes may be applied on the DTIs if specified. Compression load and hardness of the DTIs shall be determined by performing mechanical tests.
This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
1. Scope
1.1 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.
1.2 Direct tension indicators in nominal diameter sizes 1/4 through 21/2 in. are covered.
1.3 There are two Types of DTIs covered by this specification, Type 1 and Type 2.
1.3.1 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).
TABLE 1 Acceptable Range of Compression LoadA | DTI
Nominal
Diameter
(in.) | Mean Compression LoadB Range
in Pounds (lbs) | Mean Compression LoadC Range
in Pounds (lbs) |
| Grade 5 | Grade 8 | Grade 55 | Grade 105 |
| 1/4 | 2200 to 2450 | 3100 to 3450 | . . . | . . . |
| 5/16 | 3500 to 3850 | 4950 to 5500 | . . . | . . . |
| 3/8 | 5300 to 5850 | 7500 to 8300 | . . . | . . . |
| 7/16 | 7200 to 7900 | 10 100 to 11 200 | . . . | . . . |
| 1/2 | 9700 to 10 700 | 13 700 to 15 340 | 4450 to 4900 | 8500 to 9400 |
| 9/16 | 12 350 to 13 600 | 17 400 to 19 200 | 5700 to 6300 | 10 900 to 12 050 |
| 5/8 | 15 550 to 17 200 | 21 850 to 24 200 | 7050 to 7800 | 13 500 to 15 000 |
| 3/4 | 22 600 to 25 000 | 31 900 to 35 300 | 10 500 to 11 600 | 20 000 to 22 150 |
| 7/8 | 30 850 to 34 100 | 43 550 to 48 100 | 14 500 to 16 000 | 27 650 to 30 550 |
| 1 | 40 200 to 44 400 | 56 700 to 62 700 | 19 000 to 21 000 | 36 250 to 40 100 |
| 11/8 | 45, 100 to 49 850 | 73 150 to 80 900 | 23 950 to 26 450 | 47 300 to 52 300 |
| 11/4 | 56 550 to 62 550 | 91 750 to 101 450 | 30 400 to 33 600 | 59 850 to 66 150 |
| 13/8 | 69 350 to 79 750 | 112 450 to 124 250 | 38 550 to 42 600 | 73 800 to 81 600 |
| 11/2 | 83 350 to 92 150 | 135 150 to 149 400 | 44 050 to 48 700 | 89 300 to 98 700 |
| 15/8 | . . . | . . . | 55 800 to 61 700 | 106 200 to 117 400 |
| 13/4 | 121 850 to 134 650 | 177 850 to 196 500 | 59 550 to 65 850 | 124 600 to 137 750 |
| 17/8 | 154 550 to 170 800 | 206 050 to 227 750 | 75 550 to 83 500 | 144 500 to 159 700 |
| 2 | 160 050 to 177 200 | 236 850 to 261 750 | 78 650 to 86 950 | 165 800 to 183 300 |
| 21/4 | 208 400 to 230 350 | 277 900 to 307 100 | 102 050 to 112 750 | 212 900 to 235 350 |
| 21/2 | 256 500 to 283 500 | 379 600 to 419 600 | 125 400 to 138 600 | 240 550 to 265 850 |
1.3.2 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).
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 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.
2. Referenced Documents (purchase separately) 
The documents listed below are referenced within the subject standard but are not provided as part of the standard.
ASTM Standards
A193/A193M Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature or High Pressure Service and Other Special Purpose Applications
A194/A194M Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both
A307 Specification for Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength
A325 Specification for Structural Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile Strength
A354 Specification for Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners
A449 Specification for Hex Cap Screws, Bolts and Studs, Steel, Heat Treated, 120/105/90 ksi Minimum Tensile Strength, General Use
A563 Specification for Carbon and Alloy Steel Nuts
B633 Specification for Electrodeposited Coatings of Zinc on Iron and Steel
B695 Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel
F436 Specification for Hardened Steel Washers
F606 Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets
F1470 Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
F1554 Specification for Anchor Bolts, Steel, 36, 55, and 105-ksi Yield Strength
F1941 Specification for Electrodeposited Coatings on Threaded Fasteners (Unified Inch Screw Threads (UN/UNR))
ASME Standards
ASMEB18.2.8 Clearance Holes for Bolts Screws, and Studs
SAE Standard
SAEJ995 Mechanical and Material Requirements for Steel Nuts
Keywords
compressible-washer-type; direct tension indicators; DTI; load indicators; load indicating washers; tension indicators;
ICS Code
ICS Number Code 21.060.01 (Fasteners in general)
DOI: 10.1520/F2437-12
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Citing ASTM Standards
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