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- F3125 Grade A325 (Group 120) and A490 (Group 150)
- Diameters ½ to 1½ in, UNC threads
- A563 DH / C nuts, F436 hardened washers
- Plain, hot-dip or mechanically galvanized (A325)
- Snug-tight, pretensioned or slip-critical joints
- Rotational capacity tested per lot
What it is
ASTM F3125 replaced the separate A325, A490, F1852 and F2280 specifications in 2015. It covers heavy hex structural bolts in two strength groups – Group 120 (Grade A325, 120 ksi minimum tensile strength) and Group 150 (Grade A490, 150 ksi) – used in steel buildings and bridges designed to AISC 360 and the RCSC Specification.
World Steel supplies F3125 assemblies with every structural steel package for the US, Canada, the Caribbean and Latin America: bolt, nut and washer from one lot, tested together and packed per connection.
Sizes and properties
| Diameter | TPI | Head AF | Stress area | A325 min. tensile | A490 min. tensile | Pretension A / B |
|---|---|---|---|---|---|---|
| ½ in | 13 | ⅞ in | 0.142 in² | 17.0 kips | 21.3 kips | 12 / 15 kips |
| ⅝ in | 11 | 1 1/16 in | 0.226 in² | 27.1 kips | 33.9 kips | 19 / 24 kips |
| ¾ in | 10 | 1¼ in | 0.334 in² | 40.1 kips | 50.1 kips | 28 / 35 kips |
| ⅞ in | 9 | 1 7/16 in | 0.462 in² | 55.4 kips | 69.3 kips | 39 / 49 kips |
| 1 in | 8 | 1⅝ in | 0.606 in² | 72.7 kips | 90.9 kips | 51 / 64 kips |
| 1⅛ in | 7 | 1 13/16 in | 0.763 in² | 91.6 kips | 114.5 kips | 64 / 80 kips |
| 1¼ in | 7 | 2 in | 0.969 in² | 116.3 kips | 145.4 kips | 81 / 102 kips |
| 1½ in | 6 | 2⅜ in | 1.405 in² | 168.6 kips | 210.8 kips | 118 / 148 kips |
Joint types and installation
The RCSC Specification recognises snug-tight, pretensioned and slip-critical joints. Pretensioned joints are tightened by turn-of-nut, calibrated wrench, twist-off (TC) bolts or direct tension indicators to at least 70 % of the minimum tensile strength.
Grade A490 (Group 150) bolts must not be hot-dip galvanized – hydrogen embrittlement risk. Use plain finish or approved coatings.
Assemblies
Nuts: ASTM A563 Grade DH (galvanized) or C / DH (plain); washers: ASTM F436 hardened, Type 1. Lubricated, galvanized nuts and rotational-capacity testing of each lot are required for galvanized A325 assemblies.
Normas e requisitos por mercado
Normas segundo as quais a World Steel projeta, fabrica e documenta este produto – e os principais requisitos geométricos e de carga em cada mercado.
Estados Unidos
- ASTM F3125High-strength structural bolts
- RCSC 2020Specification for structural joints
- AISC 360Bolted connections, chapter J
- ASTM A563 / F436Nuts and hardened washers
- Pretension
- ≥ 0.70 × min. tensile strength (RCSC)
Austrália / NZ
- AS/NZS 1252.1Equivalent structural bolting in Australia / NZ
Resumo apenas para orientação – prevalecem a especificação do projeto, a edição da norma adotada e a autoridade competente.
Acabamentos
| Acabamento | Normas / observações |
|---|---|
| Plain / black | Oiled, for painted or indoor connections |
| Hot-dip galvanized | ASTM F2329 · ISO 10684 · AS/NZS 1214 – nuts tapped oversize and lubricated |
| Zn/Al flake | ASTM F3393 / F1136 coatings for A490 |
Perguntas frequentes
Is A325 still a standard?
A325 is now a grade within ASTM F3125 – drawings that call for A325 are supplied as F3125 Grade A325.
Can A490 bolts be galvanized?
No – hot-dip galvanizing of Group 150 bolts is not permitted; plain or approved zinc-flake coatings are used.
