ASTM F959

ASTM F959 covers the requirements for compressible washer type direct tension indicators in diameters ranging from 1/2” to 1-1/2” inclusive. These washers are capable of indicating the achievement of a specified minimum bolt tension. They are available in two grades for use with A325 and A490 structural bolts and are also available in a weathering steel option for both grades.

F959 Types

Type 325 and 325-3 For use with A325, F1852 and A325-3, F1852-3 structural bolts
Type 490 and 490-3 For use with A490, F2280 and A490-3, F2280-3 structural bolts

F959 Acceptable Compression Load Range

Diameter Type 325 and 325-3, in kips Type 490 and 490-3, in kips
1/2 12 – 14 15 – 18
5/8 19 – 23 24 – 29
3/4 28 – 34 35 – 42
7/8 39 – 47 49 – 59
1 51 – 61 64 – 77
1-1/8 64 – 77 80 – 96
1-1/4 81 – 98 102 – 122
1-3/8 97 – 117 121 – 145
1-1/2 118 – 143 148 – 178

F959 Chemical Requirements, Heat Analysis

Element Type 325 and 490 Type 325-3 and 490-3
Carbon 0.30 - 0.55%
Manganese 0.50 – 0.90%
Phosphorous, max 0.040% 0.040%
Sulfur, max 0.045% 0.050%
Silicon 0.15 – 0.35% 0.15 – 0.35%
Chromium 0.45 – 0.65%
Nickel 0.25 – 0.45%
Copper 0.25 – 0.45%
  • Weathering steel DTIs may also be made from any of the type 3 steels listed in A325 and F436
  • Weathering Steel DTIs having Copper, Sulfur, and Phosphorous conforming to the above, and having a Corrosion Resistance Index of 6 or higher calculated on the basis of the heat analysis as described in Guide 101 Predictive Method based on the data of Larabee and Coburn shall be considered acceptable.