ASTM F2437 covers the requirements for compressible washer type direct tension indicators in diameters ranging from 1/4” to 2-1/2” inclusive. These washers are capable of indicating a specified bolt tension in cap screws, bolts, anchors, and studs. They are available in two styles, and two grades within each style.
F2437 Types and Recommended Fasteners
F2437 Acceptable Compression Load Range
| Mean Compression Load Range (lbs) |
| Diameter |
Grade 5 |
Grade 8 |
Grade 55 |
Grade 105 |
| ½ |
9,700 – 10,700 |
13,700 – 15,340 |
4,450 – 4,900 |
8,500 – 9,400 |
| 5/8 |
15,550 – 17,200 |
21,850 – 24,200 |
7,050 – 7,800 |
13,500 – 15,000 |
| ¾ |
22,600 – 25,000 |
31,900 – 35,300 |
10,500 – 11,600 |
20,000 – 22,150 |
| 7/8 |
30,850 – 34,100 |
43,550 – 48,100 |
14,500 – 16,000 |
27,650 – 30,550 |
| 1 |
40,200 – 44,400 |
56,700 – 62,700 |
19,000 – 21,000 |
36,250 – 40,100 |
| 1-1/8 |
40,250 –44,450 |
73,150 – 80,900 |
23.950 – 26,450 |
47,300 – 52,300 |
| 1-1/4 |
51,100 – 56,450 |
91,750 – 101,450 |
30,400 – 33,600 |
59,850 – 66,150 |
| 1-3/8 |
61,150 – 67,600 |
112,450 – 124,250 |
38,550 – 42,600 |
73,800 – 81,600 |
| 1-1/2 |
74,350 – 82,150 |
135,150 – 149,400 |
44,050 – 48,700 |
89,300 – 98,700 |
| 1-3/4 |
74,450 – 82,300 |
177,850 – 196,500 |
59,550 – 65,850 |
124,600 – 137,750 |
| 2 |
98,000 – 108,300 |
236,850 – 261,750 |
78,650 – 86,950 |
165,800 – 183,300 |
| 2-1/4 |
127,400 – 140,800 |
277,900 – 307,100 |
102,050 – 112,750 |
212,900 – 235,350 |
| 2-1/2 |
156,750 – 173,250 |
379,600 – 419,600 |
125,400 – 138,600 |
240,550 – 265,850 |
| 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 to enable the user to select the appropriate gap criteria for the intended target tension for the application. |
F2437 Chemical Requirements, Heat Analysis
| Element |
Heat Analysis, All Types and Grades |
| Carbon |
0.30 – 0.55% |
| Manganese |
0.50 – 0.90% |
| Phosphorus |
0.040% max |
| Sulfur |
0.045% max |
| Silicon |
0.15 – 0.35% |
