Hex Bolt Identification Guide
Page Last updated 13/6/2006
Some bolts share identical head identification and have significantly different strengths.
| Identification Grade Mark |
Specification | Description | Material | Proof Load | Yield Strength Min (psi) |
Tensile Strength Min (psi) |
 |
SAE
J429 Grade 5 ASTM A449 |
Bolts, Screws, Studs |
Medium Carbon Steel | 85,000 74,000 |
92,000 thru 81,000 |
120,000 thru 105,000 |
 |
SAE
J429 Grade 5.1 |
Sems | Low or Medium Carbon Steel | 85,000 | - | 120,000 |
 |
SAE
J429 Grade 5.2 |
Bolts, Screws, Studs |
Low Carbon | 85,000 | 92,000 | 120,000 |
 |
ASTM A325 Type 1 |
High Strength Structural Bolts |
Medium Carbon | 85,000 74,000 |
92,000 thru 81,000 |
120,000 thru 105,000 |
 |
ASTM A325 Type 2 |
High Strength Structural Bolts |
Low Carbon | 85,000 | 92,000 | 120,000 |
 |
ASTM A325 Type 3 |
High Strength Structural Bolts |
Corrion Resistant Steel |
85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
 |
ASTM A354 Grade BB |
Bolts, Studs | Alloy Steel | 80,000 75,000 |
83,000 78,000 |
105,000 100,000 |
 |
ASTM A354 Grade BC |
Bolts, Studs | Alloy Steel | 105,000 95,000 |
109,000 99,000 |
125,000 115,000 |
 |
SAE
J429 Grade 7 |
Bolts, Screws | Medium Carbon Alloy Steel | 105,000 | 115,000 | 133,000 |
 |
SAE
J429 Grade 8 |
Bolts, Screws, Studs |
Medium Carbon Alloy Steel | 120,000 | 130,000 | 150,000 |
|
ASTM A354 Grade BD |
Bolts, Screws, Studs |
Alloy Steel | 120,000 | 130,000 | 150,000 |
 |
SAE
J429 Grade 8.1 |
Studs | Medium Carbon Steel | 120,000 | 130,000 | 150,000 |
 |
ASTM A490 | Structural Bolts | Alloy Steel | 120,000 | 130,000 | 150,000 thru 170,000 |
|
ISO
R898 Class 4.6 |
Bolts, Screws, Studs | Low or Median Steel | 33,000 | 36,000 | 60,000 |
|
ISO
R898 Class 5.8 |
Bolts, Screws, Studs | Low or Median Steel | 55,000 | 57,000 | 74,000 |
 |
ISO
R898 Class 8.8 |
Bolts, Screws, Studs | Median Steel | 85,000 | 92,000 | 120,000 |
 |
ISO
R898 Class 8.8 |
Bolts, Screws, Studs | Median Steel | 85,000 | 92,000 | 120,000 |
 |
ISO
R898 Class 10.9 |
Bolts, Screws, Studs | Alloy Steel | 120,000 | 130,000 | 150,000 |
 |
ISO
R898 Class 10.9 |
Bolts, Screws, Studs | Alloy Steel | 120,000 | 130,000 | 150,000 |
 |
ASTM A320 Grade B8 |
Bolts, Screws, Studs | AISI 304 | - | 30,000 | 75,000 |
 |
ASTM A320 Grade B8C |
Bolts, Screws, Studs | AISI 347 | - | 30,000 | 75,000 |
 |
ASTM A320 Grade B8T |
Bolts, Screws, Studs | AISI 321 | - | 30,000 | 75,000 |
 |
ASTM A320 Grade B8F |
Bolts, Screws, Studs | AISI 303 or 303Se |
- | 30,000 | 75,000 |
 |
ASTM A320 Grade B8F |
Bolts, Screws, Studs | AISI 316 | - | 30,000 | 75,000 |
 |
ASTM A320 Grade B8 |
Bolts, Screws, Studs | AISI 304 | - | 50,000 Thru 100,000 |
105,000 Thru 125,000 |
 |
ASTM A320 Grade B8C |
Bolts, Screws, Studs | AISI 347 | - | 50,000 Thru 100,000 |
105,000 Thru 125,000 |
 |
ASTM A320 Grade B8F |
Bolts, Screws, Studs | AISI 303 or 303Se |
- | 50,000 Thru 100,000 |
105,000 Thru 125,000 |
 |
ASTM A320 Grade B8M |
Bolts, Screws, Studs | AISI 316 | - | 50,000 Thru 100,000 |
105,000 Thru 125,000 |
 |
ASTM A320 Grade B8T |
Bolts, Screws, Studs | AISI 321 | - | 50,000 Thru 100,000 |
105,000 Thru 125,000 |
|
ASTM A193 Grade B8T |
Bolts, Screws, Studs | AISI 321 | 30,000 | 75,000 | |
|
ASTM A193 Grade B8 |
Bolts, Screws, Studs | AISI 304 | - | 50,000 thru 100,000 |
100,000 thru 125,000 |
|
ASTM A193 Grade B8C |
Bolts, Screws, Studs | AISI 347 | - | 50,000 thru 100,000 |
100,000 thru 125,000 |
|
ASTM A193 Grade B8M |
Bolts, Screws, Studs | AISI 316 | - | 50,000 thru 95,000 |
90,000 thru 125,000 |
|
ASTM A193 Grade B8T |
Bolts, Screws, Studs | AISI | - | 50,000 thru 95,000 |
100,000 thru 120,000 |
|
SAE
J429 Grade 1 |
Bolts, Screws, Studs | Low or Median Carbon Steel | 33,000 | 36,000 | 60,000 |
 |
ASTM A320 Grade L7B |
Bolts, Screws, Studs, Low temp Appl. |
AISI 4137 | - | 105,000 | 125,000 |
 |
ASTM A320 Grade L7C |
Bolts, Screws, Studs, Low temp Appl. |
AISI 8740 | - | 105,000 | 125,000 |