A490 Heavy Hex Bolts
The high-strength structural bolt: alloy steel, 150 to 173 ksi tensile, ½ to 1½ in., never hot-dip galvanized — with the twist-off F2280 and metric A490M variants in the same specification.
Larger heads for higher bearing area in heavy construction and flange service. Heavy pattern heads to ASME B18.2.1, commonly in A193 B7 and A325/A490 structural grades.
Grade A490 in ASTM F3125 is the 150 ksi structural bolt, made from quenched-and-tempered alloy steel at 33 to 38 HRC. It uses the same heavy hex head and short thread as A325 and the same ½ to 1½ in. size range, but carries 25 percent more load. Because of its hardness it must not be hot-dip galvanized; the zinc-aluminium coating under ASTM F3393 (which replaced F1136 and F2833) is the qualified coating, and plain bolts are supplied lightly oiled.
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What A490 must meet.
| Grade / condition and size | Tensile strength, min (ksi) | Yield or proof, min (ksi) | Elongation, min (%) | Reduction of area, min (%) | Hardness |
|---|---|---|---|---|---|
| A490 / F2280 — ½ to 1½ in. | 150 (173 max) | 120 proof (130 by yield method) | — | — | 33–38 HRC (311–352 HBW) |
Values per ASTM F3125/F3125M-23 Tables 5 and 7 (verified against the specification). Confirm the edition called out on your purchase order with our estimating team.
Quenched and tempered at 800 °F minimum. Not hot-dip galvanized or electroplated because of hydrogen embrittlement risk at this hardness.
Full A490 (F3125) data sheet: chemistry, physical properties and standards →
Made to standard or to your drawing.
- Heavily loaded steel building and bridge connections
- Crane, hoist and heavy-equipment structural joints
- Offshore and module structural connections
- Connections where A325 bolt count cannot be increased