ASTM, SAE and ISO Grade Markings for Steel Fasteners
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| Identification Grade Mark |
Specification | Fastener Description |
Material | Nominal Size Range (in.) |
Mechanical Properties | ||
| Proof Load(psi) |
Yield Strength Min (psi) |
Tensile Strength Min (psi) |
|||||
 NoGradeMark |
SAE J429 Grade 1 |
Bolts, Screws, Studs |
Low or Medium Carbon Steel |
1/4 thru 1-1/2 |
33,000 | 36,000 | 60,000 |
| ASTM A307 Grades A&B |
Low Carbon Steel |
1/4 thru 4 | — | — | |||
| SAE J429 Grade 2 |
Low or Medium Carbon Steel |
1/4 thru 3/4 Over 3/4 to 1-1/2 |
55,000 33,000 |
57,000 36,000 |
74,000 60,000 |
||
| NoGradeMark |
SAE J429 Grade 4 |
Studs | Medium Carbon Cold Drawn Steel |
1/4 thru 1-1/2 |
— | 100,000 | 115,000 |
| B5 |
ASTM A193 Grade B5 |
AISI 501 | 1/4 Thru 4 | — | 80,000 | 100,000 | |
| B6 |
ASTM A193 Grade B6 |
AISI 410 | 85,000 | 110,000 | |||
| B7 |
ASTM A193 Grade B7 |
AISI 4140, 4142, OR 4105 |
1/4 thru 2-1/2Over 2-1/2 thru 4Over 4 thru 7 | ——- | 105,000 95,00075,000 |
125,000 115,000100,000 |
|
| B16 |
ASTM A193 Grade B16 |
CrMoVa Alloy Steel |
105,000 95,00085,000 |
125,000 115,000100,000 |
|||
| B8 |
ASTM A193 Grade B8 |
AISI 304 | 1/4 and larger | — | 30,000 | 75,000 | |
| B8C |
ASTM A193 Grade B8C |
AISI 347 | |||||
| B8M |
ASTM A193 Grade B8M |
AISI 316 | |||||
| B8T |
ASTM A193 Grade B8T |
Bolts, Screws, Studs for High-Temperature Service | AISI 321 | 1/4 and larger |
— | 30,000 | 75,000 |
| B8 |
ASTM A193 Grade B8 |
AISI 304Strain Hardened | 1/4 thr 3/4Over 3/4 thru 1Over 1 thru 1-1/4Over 1-1/4 thru 1-1/2 | ——— | 100,000 80,00065,000 50,000 |
125,000 115,000105,00 0100,000 |
|
| B8C |
ASTM A193 Grade B8C |
AISI 347Strain Hardened | |||||
| B8M |
ASTM A193 Grade B8M |
AISI 316Strain Hardened | 95,000 80,00065,000 50,000 |
110,000 100,00095,00 090,000 |
|||
| B8T |
ASTM A193 Grade B8T |
AISI 321Strain Hardened | 100,000 80,00065,000 50,000 |
125,000 115,000105,000 100,000 |
|||
| L7 |
ASTM A320 Grade L7 |
Bolts, Screws, Studs for Low-Temperature Service | AISI 4140,4142 or 4145 | 1/4 thru 2-1/2 | — | 105,000 | 125,000 |
| L7A |
ASTM A320 Grade L7A |
AISI 4037 | |||||
| L7B |
ASTM A320 Grade L7B |
AISI 4137 | |||||
| L7C |
ASTM A320 Grade LC7 |
AISI 8740 | |||||
| L43 |
ASTM A320 Grade L43 |
AISI 4340 | 1/4 thru 4 | — | 105,000 | 125,000 | |
| B8 |
ASTM A320 Grade B8 |
Bolts, Screws, Studs for Low-Temperature Service | AISI 304 | 1/4 and larger | — | 30,000 | 75,000 |
| B8C |
ASTM A320 Grade B8C |
AISI 347 | |||||
| B8T |
ASTM A320 Grade B8T |
AISI 321 | |||||
| B8F |
ASTM A320 Grade B8F |
AISI 303or 303Se | |||||
| B8M |
ASTM A320 Grade B8M |
AISI 316 | |||||
| B8 |
ASTM A320 Grade B8 |
AISI 304 | 1/4 thru 3/4Over 3/4 thru 1Over 1 thru 1-1/4Over 1-1/4 thru 1-1/2 | ——— | 100,000 80,00065,00 50,00 |
100,000 80,00065,00 50,00 |
|
| B8C |
ASTM A320 Grade B8C |
AISI 347 | |||||
| B8F |
ASTM A320 Grade B8F |
AISI 303or 303Se | |||||
| B8M |
ASTM A320 Grade B8M |
AISI 316 | |||||
| B8T |
ASTM A320 Grade B8T |
AISI 321 | |||||
 |
SAE J429 Grade 5 |
Bolts, Screws, Studs | Medium Carbon Steel, Quenched and Tempered | 1/4 thru 1Over 1 to 1-1/2 | 85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
| ASTM A449 | 1/4 thru 1Over 1 to 1-1/2Over 1-1/2 thru 3 | 85,000 74,000 55,000 |
92,000 81,00058,000 |
120,000 105,00090,000 |
|||
 |
SAE J429 Grade 5.1 |
Sems | Low or Medium Carbon Steel, Quenched and Tempered |
No. 6thru 3/8 | 85,000 | — | 120,000 |
 |
SAE J429 Grade 5.2 |
Bolts, Screws, Studs | Low Carbon Martensitic Steel, Quenched and Tempered |
1/4 thru 1 | 85,000 | 92,000 | 120,000 |
| A325 |
ASTM A325 Type 1 |
High Strength Structural Bolts | Medium Carbon Steel, Quenched and Tempered |
1/2 thru 1 1-1/8 thru 1-1/2 |
85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
| A325 |
ASTM A325 Type 2 |
Low Carbon Martensitic Steel, Quenched and Tempered |
1/2 thru 1 | 85,000 | 92,000 | 120,000 | |
| A325 |
ASTM A325 Type 3 |
Atmospheric Corrosion Resisting Steel, Quenched and Tempered |
1/2 thru 1 1-1/8 thru 1-1/2 |
85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
|
 BB |
ASTM A354 Grade BB |
Bolts, Studs | Alloy Steel, Quenched and Tempered | 1/4 thru 2-1/2 2-3/4 thru 4 |
80,000 75,000 |
83,000 78,000 |
105,000 100,000 |
 BC |
ASTM A354 Grade BC |
105,000 95,000 |
109,000 99,000 |
125,000 115,000 |
|||
 |
SAE J429 Grade 7 |
Bolts, Screws | Medium Carbon Alloy Steel, Quenched and Tempered 4 |
1/4 thru 1-1/2 |
105,000 | 115,000 | 133,000 |
 |
SAE J429Grade 8 | Bolts, Screws, Studs | Medium Carbon Alloy Steel, Quenched and Tempered |
1/4 thru 1-1/2 | 120,000 | 130,000 | 150,000 |
| ASTM A354 Grade BD |
Alloy Steel, Quenched and Tempered 4 |
||||||
| No GradeMark |
SAE J429 Grade 8.1 |
Studs | Medium Carbon Alloy or SAE 1041 Modified Elevated Temperature Drawn Steel |
1/4 thru 1-1/2 |
120,000 | 130,000 | 150,000 |
| A490 |
ASTM A490 | High Strength Structural Bolts |
Alloy Steel, Quenched and Tempered |
1/2 thru 1-1/2 |
120,000 | 130,000 | 150,000 min 170,000 max |
| No GradeMark |
ISO R898 Class 4.6 |
Bolts, Screws, Studs | Medium Carbon Steel, Quenched and Tempered | All Sizes thru 1-1/2 |
33,000 | 36,000 | 60,000 |
| No GradeMark |
ISO R898 Class 5.8 |
55,000 | 57,000 | 74,000 | |||
| 8.8or88 |
ISO R898 Class 8.8 |
Alloy Steel, Quenched and Tempered | 85,000 | 92,000 | 120,000 | ||
| 10.9or109 |
ISO R898 Class 10.9 |
120,000 | 130,000 | 150,000 | |||
FASTENER IDENTIFICATION
MARKING
| Grade Identification Marking |
Specification | Material | Nominal SizeIn. | Proof LoadStressksi |
Hardness Rockwell |
See Note |
|
| Min | Max | ||||||
 No Mark |
ASTM A563 – Grade 0 |
Carbon Steel |
1/4 thru 1-1/2 |
69 | B55 | C32 | 3,4 |
| ASTM A563 – Grade A |
Carbon Steel |
1/4 thru 1-1/2 |
90 | B68 | C32 | 3,4 | |
| ASTM A563 – Grade B | Carbon Steel | 1/4 thru 1 | 120 | B69 | C32 | 3,4 | |
| over 1 thru 1-1/2 |
105 | ||||||
 |
ASTM A563 – Grade C |
Carbon Steel May be Quenchedand Tampered |
1/4 thru 4 | 144 | B78 | C38 | 5 |
 |
ASTM A563 – Grade C3 |
Atmospheric CorrosionResistant SteelMay be Quenchedand Tampered |
1/4 thru 4 | 144 | B78 | C38 | 5,9 |
 |
ASTM A563 – Grade D |
Carbon Steel May be Quenchedand Tampered |
1/4 thru 4 | 150 | B84 | C38 | 6 |
 |
ASTM A563 – Grade DH |
Carbon Steel Quenchedand Tampered |
1/4 thru 4 | 175 | C24 | C38 | 6 |
 |
ASTM A563 – Grade DH3 |
Atmospheric CorrosionResistant Steel,Quenchedand Tampered |
1/4 thru 4 | 175 | C24 | C38 | 5,9 |
 |
ASTM A194 – Grade 1 |
Carbon Steel |
1/4 thru 4 | 130 | B70 | — | 7 |
 |
ASTM A194 – Grade 2 |
Medium CarbonSteel |
1/4 thru 4 | 150 | 159 | 352 | 7,8 |
 |
ASTM A194 – Grade 2H |
Medium Carbon Steel, Quenchedand Tempered |
1/4 thru 4 | 175 | C24 | C38 | 7 |
 |
ASTM A194 – Grade 2HM |
Medium Carbon Steel, Quenchedand Tempered |
1/4 thru 4 | 150 | 159 | 237 | 7,8 |
 |
ASTM A194 – Grade 4 |
Medium Carbon Alloy Steel,Quenchedand Tempered |
1/4 thru 4 | 175 | C24 | C38 | 7 |
 |
ASTM A194 – Grade 7 |
Medium Carbon Alloy Steel,Quenchedand Tempered |
1/4 thru 4 | 175 | C24 | C38 | 7 |
 |
ASTM A194 – Grade 7M |
Medium Carbon Alloy Steel,Quenchedand Tempered |
1/4 thru 4 | 150 | 159 | 237 | 7 |
| See Note 1,2 | 10 | ||||||
NOTES:
- In addition to the indicated grade marking, all grades, except A563 grades O, A and B, must be marked for manufacturer identification.
- The markings shown for all grades of A194 nuts are for cold formed and hot forged nuts. When nuts are machined from bar stock the nut must be additionally marked with the letter ‘B’.
- Nuts are not required to be marked unless specified by the purchaser. When marked, the identification marking shall be the grade letter O, A or B.
- Properties shown are those of nonplated or noncoated coarse thread hex nuts.
- Properties shown are those of coarse thread heavy hex nuts.
- Properties shown are those of coarse thread heavy hex nuts.
- Properties shown are those of coarse 8-pitch thread heavy hex nuts.
- Hardnesses are Brinell Hardness Numbers.
- The nut manufacturer, at his option, may add other markings to indicate the use of atmospheric corrosion resistant steel.
- Specifications —
- ASTM A563 — Carbon and Alloy Steel Nuts.
ASTM A194/A194M — Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service.