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Dti Washer, Galvanized

Selected F959 Load Indicating Flat Washer Hot Dipped Galvanized3/4 F959 Direct Tension Indicator Washer, Galvanized
F959 Load Indicating Flat Washer Hot Dipped Galvanized3/4 F959 Direct Tension Indicator Washer, Galvanized

ASTM F959, Type A325 Direct Tension Indicator (DTI) washers are used to indicate the correct bolt tension when an A325 structural bolt is installed. The DTI is placed under a hardened surface such as a bolt head, nut, or hardened washer, with the bumps facing away from the structural steel. As the bolt is tensioned, the clamping force flattens the bumps, reducing the gap. The operator then checks the gap between the bumps to ensure the bumps have been crushed to within a determined tolerance, which results in the bolt reaching its proper tension. Dimensional specifications are governed by ASME B18.2.6. Available in mechanical galvanized finish, which provides a corrosion resistant zinc coating.

Products

Governing Standards

ASTM F959 Covers the requirements for compressible-washer-type direct tension indicators capable of indicating the achievement of a specified minimum bolt tension in a structural bolt.
ASME B18.2.6 Covers the general and dimensional data for five products in the inch series recognized as American National Standard. These five structural products include: (a) Heavy Hex Structural Bolts: ASTM A325 or ASTM A490; (b) Heavy Hex Nuts: ASTM A563; (c) Hardened Steel Washers; Circular, Circular Clipped or Beveled: ASTM F436; (d) Compressible Washer-Type Direct Tension Indicators: ASTM F959; (e) Twist-Off-Type Tension Control Structural Bolts: Heavy Hex and Round: ASTM F1852.

Chemical Properties

Per ASTM F959-2009
Grade Carbon Manganese Phosphorus Sulfur Silicon
% by weight % by weight % by weight % by weight % by weight
DTI - Type 325 0.30-0.55 0.50-0.90 0.04 0.045 0.15-0.35

Mechanical Properties

Per ASTM F959-2009
Acceptable Range of
Compression Loads
Size Type A325
(1000 lbs)
1/2 12-14
5/8 19-23
3/4 28-34
7/8 39-47
1 51-61
1 1/8 56-67
1 1/4 71-85
1 3/8 85-102
1 1/2 103-124

Dimensional Specifications

Direct Tension Indicator washer dimensions
Per ASME B18.2.6-2011
Size A B C Number of
Protrusions
(Equally
Spaced)		 E F
Inside
Diameter		 Protrusion
Tangential
Diameter		 Outside
Diameter		 Thickness
Without
Protrusion		 With
Protrusion
Min Max Max Min Max Min Max
1/2 0.523 0.527 0.788 1.167 1.187 4 0.104 0.180
5/8 0.654 0.658 0.956 1.355 1.375 4 0.126 0.220
3/4 0.786 0.790 1.125 1.605 1.625 5 0.126 0.230
7/8 0.917 0.921 1.294 1.855 1.875 5 0.142 0.240
1 1.048 1.052 1.463 1.980 2.000 6 0.158 0.270
1 1/8 1.179 1.183 1.631 2.230 2.250 6 0.158 0.270
1 1/4 1.311 1.315 1.800 2.480 2.500 7 0.158 0.270
1 3/8 1.442 1.446 1.969 2.730 2.750 7 0.158 0.270
1 1/2 1.573 1.577 2.138 2.980 3.000 8 0.158 0.270
  1. All dimensions are in inches.