A325 Heavy Hex Bolts
The structural steel connection bolt: heavy hex head, 120 ksi tensile, ½ to 1½ in., quenched and tempered, with the twist-off F1852 and metric A325M 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.
ASTM F3125 consolidated the old A325, A490, F1852 and F2280 specifications. Grade A325 is the 120 ksi heavy hex structural bolt used in bolted steel connections, in Type 1 (plain carbon, boron or alloy steel) and Type 3 (weathering steel). It is limited to ½ through 1½ in., has a short thread length so the shank is in the shear plane, and is supplied with A563 DH nuts and F436 washers as a matched assembly.
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What A325 must meet.
| Grade / condition and size | Tensile strength, min (ksi) | Yield or proof, min (ksi) | Elongation, min (%) | Reduction of area, min (%) | Hardness |
|---|---|---|---|---|---|
| A325 / F1852 — ½ to 1½ in. | 120 | 85 proof (92 by yield method) | — | — | 25–34 HRC (253–319 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. Loads per thread size are listed in Table 5; the stress basis is shown here.
Quenched and tempered at 800 °F minimum. Hot-dip galvanized A325 bolts are tested after galvanizing; A490 must not be hot-dip galvanized.
Full A325 (F3125) data sheet: chemistry, physical properties and standards →
Made to standard or to your drawing.
- Bolted steel building and bridge connections
- Pipe-rack and module structural joints
- Equipment structural frames
- Crane runway and rail connections