ASTM A325 Specifications

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

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In 2016, ASTM A325 was officially withdrawn and replaced by ASTM F3125, in which A325 now becomes a grade under the F3125 specification.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 1Medium carbon, carbon boron, or medium carbon alloy steel.
TYPE 2Withdrawn November 1991.
TYPE 3Weathering steel.
TFully threaded A325. (Restricted to 4 times the diameter in length)
MMetric A325.

A325 Connection Types

SCSlip critical connection.
NBearing type connection with threads included in the shear plane.
XBearing-type connection with threads excluded from the shear plane.

A325 Mechanical Properties

SizeTensile, ksiYield, ksiElong. %, minRA %, min
12 – 1120 min92 min1435
118 – 112105 min81 min1435

A325 Type 1 Chemical Properties

Heat Analysis120ksi, %150ksi, %
Carbon0.30 – 0.520.30 – 0.48*
Manganese0.60 min0.60 min
Phosphorus0.035 max0.035 max
Sulfur0.040 max0.040 max
Silicon0.15 – 0.30
Boron0.003 max0.003 max
*Carbon 0.35-0.53% for 1-1/2” A490/150ksi bolts

A325 Type 3 Chemical Properties

Heat Analysis120ksi, % Comp A120ksi, % Comp B120ksi, % Index150ksi, % Index
Carbon0.33 – 0.400.38 – 0.480.30 – 0.520.30 – 0.53
Manganese0.90 – 1.200.70 – 0.900.60 min0.60 min
Phosphorus0.035 max0.035 max0.035 max0.035 max
Sulfur0.040 max0.040 max0.040 max0.040 max
Silicon0.15 – 0.300.30 – 0.50
Copper0.25 – 0.450.20 – 0.400.20 – 0.600.20 – 0.60
Nickel0.25 – 0.450.50 – 0.800.20 min*0.20 min*
Chromium0.45 – 0.650.50 – 0.800.20 min0.20 min
Molybdenum0.06 max0.10 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

Type 1Type 3Type 1Type 3
A563C, C3, D, DH, DH3A563DHA563C3, DH3F436-1F436-3
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.