Note: In 2016, ASTM A490 was officially withdrawn and replaced by
ASTM F3125, in which A490 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 A490 specification on our website for reference and
informational purposes only.
Prior to its withdrawl in 2016, the ASTM A490 specification covered quenched and tempered, alloy steel,
heavy hex structural bolts from 1/2″
diameter through 1-1/2″ diameter with a minimum 150 ksi tensile. 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. A490 bolts are similar
in application and dimensions to A325 heavy hex structural bolts but are made from an alloy steel rather
than a medium carbon steel, resulting in a higher strength fastener. The A490 specification is applicable
to heavy hex structural bolts only. For bolts with different thread lengths than specified for structural
bolts but with similar mechanical properties, see SpecificationÂ
A354 grade BD. ASTM A490 bolts shall not be coated by hot-dip galvanizing, mechanical deposition, or
electroplating with zinc due to the potential risk of hydrogen embrittlement. ASTM has approved coating
A490 bolts with Zinc/Aluminum Corrosion Protective Coatings per ASTM F1136 Grade 3, commercially called
dacromet. Additional testing in the form of Magnetic Particle Inspection for Longitudinal Discontinuities
and Transverse Cracks is a requirement of the A490 specification.
| A490 Types |
| Â TYPE 1 |
Medium carbon and alloy steel. |
| Â TYPE 2 |
Withdrawn in 2002. |
| Â TYPE 3 |
Weathering steel. |
|
|
| M |
Metric A490. |
| A490 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. |
| A490 Mechanical Properties |
| Size |
Tensile, ksi |
Yield, ksi |
Elong. %, min |
RA %, min |
| 1/2 - 1-1/2 |
150-173 |
130 |
14 |
40 |
| A490 Chemical Properties |
| Type 1 Bolts |
| Element |
Sizes 1/2 to 1-3/8 |
Size 1-1/2 |
| Carbon, max |
0.30 - 0.48% |
0.35 - 0.53% |
| Phosphorus, max |
0.040% |
0.040% |
| Sulfur, max |
0.040% |
0.040% |
| Alloying Elements |
* |
* |
| * Steel, as defined by the American Iron and Steel Institute, shall be considered to be
alloy when the maximum range given for the content of alloying elements exceeds one of more of the
following limits: Manganese, 1.65%, silicon, 0.60%, copper, 0.60%, or in which a definite range or a minimum
quantity of any of the following elements is specified or required within the limits of the recognized field
of constructional alloy steels: aluminum, chromium up to 3.99%, cobalt, columbium, molybdenum, nickel, titanium,
tungsten, vanadium, zirconium or any other alloying elements added to obtain a desired alloying effect. |
| Type 3 Bolts |
| Element |
Sizes 1/2 to 3/4 |
Size above 3/4 |
| Carbon |
0.20 - 0.53% |
0.30 - 0.53% |
| Manganese, min |
0.40% |
0.40% |
| Phosphorus, max |
0.035% |
0.035% |
| Sulfur, max |
0.040% |
0.040% |
| Copper |
0.20 - 0.60% |
0.20 - 0.60% |
| Chromium, min |
0.45% |
0.45% |
| Nickel, min |
0.20% |
0.20% |
| or |
|
|
| Molybdenum, min |
0.15% |
0.15% |
