This chart detailed bolt strength requirements by grade. All specifications below are per ASTM. For more information on fasteners, visit our Fastener Learning Hub.
Bolt Strength Requirement By Grade Chart
| Specification | Material | Nominal Size (Inches) | Proof Load Min (ksi) | Strength Min (ksi) | Hardness Min | Hardness Max |
|---|---|---|---|---|---|---|
| A307 Grade A | Low or Medium Carbon Steel | 1/4″ to 4″ | – | 60 | B69 | B100 |
| A307 Grade B | Low or Medium Carbon Steel | 1/4″ to 4″ | – | 60 min 100 max |
B69 | B95 |
| F1554 Grade 36 | Low or Medium Carbon Steel | 1/4″ to 4″ | – | 58 min 80 max |
– | – |
| F1554 Grade 55 | Low or Medium Carbon Steel | 1/4″ to 2″ 2-1/4″ to 2-1/2″ 2-3/4″ to 3″ 3-3/4″ to 4″ |
– | 75 min 95 max |
– | – |
| F1554 Grade 105 | Medium Carbon Alloy Steel, Q & T |
1/4″ to 3″ | – | 125 min 150 max |
– | – |
| A193/A320 Grade B8 |
AISI SS304 Stainless |
All Included No Restrictions |
– | 75 | – | B96 |
| A193/A320 Grade B8M |
AISI SS316 Stainless |
All Included No Restrictions |
– | 75 | – | B96 |
| F3125 Grade A325 Type 1 |
Medium Carbon Steel Q & T |
1/2″ to 1″ | 85 | 120 | C25 | C34 |
| F3125 Grade A325 Type 3 |
Atomspheric Corrosion Resistant Steel, Q & T |
1-1/8″ to 1-1/2″ | 74 | 105 | C19 | C30 |
| A449 Type 1 or 3 |
Medium Carbon Steel Q & T |
1-1/4″ to 1″ 1-1/8″ to 1-1/2″ 1-5/8″ to 3″ |
85 74 55 |
120 105 90 |
C25 C19 B91 |
C34 C30 B100 |
| A193 Grade B7 |
Medium Carbon Alloy Steel, Q & T |
1/4″ to 2-1/2″ 2-5/8″ to 4″ 4-1/8″ to 7″ |
– | 125 115 100 |
– | C35 C35 C35 |
| A193 Grade B7M |
ANSI 4140, 4142, or 4145 |
1/4″ to 2-1/2″ | – | 125 | – | – |
| A354 Grade BC |
Medium Carbon Alloy Steel, Q & T |
1/4″ to 2-1/2″ 2-5/8″ to 4″ |
105 95 |
125 115 |
C26 C22 |
C36 C33 |
| F3125 Grade A490 Type 1 |
Medium Carbon Alloy Steel, Q & T |
1/2″ to 1″ | 120 | 150 min 173 max |
C33 | C38 |
| F3125 Grade A490 Type 3 |
Atmospheric Corrosion Resistant Steel, Q & T |
1/2″ to 1-1/2″ | 120 | 150 min 173 max |
C33 | C38 |
| A354 Grade BD |
Medium Carbon Alloy Steel, Q & T |
1/4″ to 2-1/2″ 2-5/8″ to 4″ |
120 105 |
150 140 |
C3 C313 |
C39 C39 |