Torque-Tension — T = K · d · F
Torque T
—
lbf·in
Torque (ft·lbf)
—
ft·lbf
Clamp Force
—
lbf
Grade-Based Preload
Proof Load Stress
—
ksi or MPa
Clamp Force
—
lbf or N
Torque Required
—
lbf·in or N·mm
Nut factors: K=0.10 (lubricated), K=0.15 (cadmium plate), K=0.20 (plain steel), K=0.22 (zinc plate), K=0.25–0.30 (dry/rusty)
Bolt Grade Properties Reference
| Grade | Proof (ksi) | Yield (ksi) | UTS (ksi) | Proof (MPa) | Yield (MPa) | UTS (MPa) |
|---|---|---|---|---|---|---|
| SAE Grade 2 (1/4–3/4") | 55 | 57 | 74 | 379 | 393 | 510 |
| SAE Grade 5 (1/4–1") | 85 | 92 | 120 | 586 | 634 | 827 |
| SAE Grade 8 (1/4–1.5") | 120 | 130 | 150 | 827 | 896 | 1034 |
| ASTM A307 (all) | — | — | 60 | — | — | 414 |
| ASTM A325 (≤1") | 85 | 92 | 120 | 586 | 634 | 827 |
| ASTM A325 (>1") | 74 | 81 | 105 | 510 | 558 | 724 |
| ASTM A490 (all) | 120 | 130 | 150 | 827 | 896 | 1034 |
| ISO 4.6 | 225 | — | — | — | 240 | 400 |
| ISO 8.8 | — | 93 | 116 | — | 640 | 800 |
| ISO 10.9 | — | 130 | 151 | — | 900 | 1040 |
| ISO 12.9 | — | 157 | 177 | — | 1080 | 1220 |
Tensile Stress Areas (in²): 1/4-20=0.0318, 5/16-18=0.0524, 3/8-16=0.0775, 1/2-13=0.1419, 5/8-11=0.2260, 3/4-10=0.3340, 7/8-9=0.4620, 1-8=0.6057
Bolt Circle Layout
Bolt Spacing (arc)
—
in
Bolt Pitch Angle
—
°
| # | X | Y | Angle (°) |
|---|