Prior to its withdrawl in 2016, the ASTM A325 specifications covered high strength heavy hex structural bolts from 1/2″ diameter through 1-1/2″ diameter. These bolts are intended for use in structural connections and therefore have shorter thread lengths than standard hex bolts. Refer to the Structural Bolts page of our site for thread lengths and other related dimensions.
This specification is applicable to heavy hex structural bolts only. For bolts of other configurations and thread lengths with similar mechanical properties.
ASTM A325 Specifications
Bolts for general applications, including anchor bolts, are covered by Specification A449. Also refer to Specification A449 for quenched and tempered steel bolts and studs with diameters greater than 1-1/2″ but with similar mechanical properties.
In 2016, ASTM A325 was officially withdrawn and replaced by ASTM F3125, in which A325 now becomes a grade under the F3125 specification. The F3125 specification is a consolidation and replacement of six ASTM standards, including; A325, A325M, A490, A490M, F1852, and F2280. We are choosing to keep this technical information about the now obsolete A325 specification on our website for reference and informational purposes only.
A325 Types
TYPE 1
Medium carbon, carbon boron, or medium carbon alloy steel.
TYPE 2
Withdrawn November 1991.
TYPE 3
Weathering steel.
T
Fully threaded A325. (Restricted to 4 times the diameter in length)
M
Metric A325.
A325 Connection Types
SC
Slip critical connection.
N
Bearing type connection with threads included in the shear plane.
X
Bearing-type connection with threads excluded from the shear plane.
A325 Mechanical Properties
Size
Tensile, ksi
Yield, ksi
Elong. %, min
RA %, min
1⁄2 – 1
120 min
92 min
14
35
11⁄8 – 11⁄2
105 min
81 min
14
35
A325 Type 1 Chemical Properties
Heat Analysis
120ksi, %
150ksi, %
Carbon
0.30 – 0.52
0.30 – 0.48*
Manganese
0.60 min
0.60 min
Phosphorus
0.035 max
0.035 max
Sulfur
0.040 max
0.040 max
Silicon
0.15 – 0.30
–
Boron
0.003 max
0.003 max
Copper
–
–
Nickel
–
–
Chromium
–
–
Molybdenum
–
–
*Carbon 0.35-0.53% for 1-1/2” A490/150ksi bolts
A325 Type 3 Chemical Properties
Heat Analysis
120ksi, % Comp A
120ksi, % Comp B
120ksi, % Index
150ksi, % Index
Carbon
0.33 – 0.40
0.38 – 0.48
0.30 – 0.52
0.30 – 0.53
Manganese
0.90 – 1.20
0.70 – 0.90
0.60 min
0.60 min
Phosphorus
0.035 max
0.035 max
0.035 max
0.035 max
Sulfur
0.040 max
0.040 max
0.040 max
0.040 max
Silicon
0.15 – 0.30
0.30 – 0.50
Copper
0.25 – 0.45
0.20 – 0.40
0.20 – 0.60
0.20 – 0.60
Nickel
0.25 – 0.45
0.50 – 0.80
0.20 min*
0.20 min*
Chromium
0.45 – 0.65
0.50 – 0.80
0.20 min
0.20 min
Molybdenum
0.06 max
0.10 min*
0.10 min*
*Either Nickel or Molybdenum must be present in the amount specified *Corrosion Index based on ASTM Guide G101
A325 Recommended Hardware
Nuts
Washers
Type 1
Type 3
Type 1
Type 3
Plain
Galvanized
Plain
A563C, C3, D, DH, DH3
A563DH
A563C3, DH3
F436-1
F436-3
Note: Nuts conforming to A194 Grade 2H are a suitable substitute for use with A325 heavy hex structural bolts. The ASTM A563 Nut Compatibility Charthas a complete list of specifications.
