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 |