In the article on ASME specifications for fastener materials, information was given about scope of fastener material for various ASME grades. In ASME specifications, detail information is given about mechanical properties and marking of fasteners. Marking on a fastener is carried out to identify fastener material. In this article information is given about mechanical properties and grade marking on fasteners. Information about non ferrous material used for making fasteners is also included. For detail information, please refer specification.
Mechanical Properties and Grade Marking
The proof load of a bolt, screw or stud is the specified load the product must withstand without permanent set. The proof load of a nut is the axially applied load the nut must withstand without thread stripping or rupture.
Usually fastener standards specify two types of marks to be on the head of a bolt. The manufacturer’s mark is a symbol identifying the manufacturer (or importer). This is the organization that accepts the responsibility that the fastener meets specified requirements. The grade mark is a standardized mark that identifies the material properties that the fastener meets. Both marks are usually located on the top of the bolt head, most standards indicating that the marks can be raised or depressed. Raised marks are usually preferred by manufacturers because these can only be added during the forging process whereas depressed marks can be added subsequently (possibly with illegitimate marks).
For ready reference tables are reproduced below from internet showing mechanical properties and grade marking for fasteners. They give information about SAE, ASTM / ASME and ISO specifications. Some information is corrected but correctness of information on SAE specification and MECHANICAL REQUIREMENTS FOR STAINLESS STEEL & NON-FERROUS FASTENERS given in the tables has not been verified.
ASTM, SAE AND ISO GRADE MARKINGS AND MECHANICAL PROPERTIES FOR STEEL FASTENERS
| Identification Grade Mark |
Specification | Fastener Description |
Material | Nominal Size Range (in.) |
Mechanical Properties | ||
|---|---|---|---|---|---|---|---|
| Proof Load (psi) |
Yield Strength Min (psi) |
Tensile Strength Min (psi) |
|||||
| No Grade Mark |
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 |
||
| No Grade Mark |
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 |
Bolts, Screws, Studs for High-Temperature Service. Class 1: Carbide solution treated |
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 2-1/2 Over 2-1/2 thru 4 Over 4 thru 7 |
– – – |
105,000 95,000 75,000 |
125,000 115,000 100,000 |
|
| B16 | ASTM A193 Grade B16 |
CrMoVa Alloy Steel | 105,000 95,000 85,000 |
125,000 110,000 100,000 |
|||
| B8 | ASTM A193 Grade B8 Class 1 |
AISI 304 | 1/4 and larger | – | 30,000 | 75,000 | |
| B8C | ASTM A193 Grade B8C Class 1 |
AISI 347 | |||||
| B8M | ASTM A193 Grade B8M Class 1 |
AISI 316 | |||||
| B8T | ASTM A193 Grade B8T Class 1 |
AISI 321 | |||||
| B8 | ASTM A193 Grade B8 Class 2 |
Bolts, Screws, Studs for High-Temperature Service. Class 2: Carbide solution treated and strain hardened. |
AISI 304 Strain Hardened |
1/4 thr 3/4 Over 3/4 thru 1 Over 1 thru 1-1/4 Over 1-1/4 thru 1-1/2 |
– – – – |
100,000 80,000 65,000 50,000 |
125,000 115,000 105,000 100,000 |
| B8C | ASTM A193 Grade B8C Class 2 |
AISI 347 Strain Hardened |
|||||
| B8M | ASTM A193 Grade B8M Class 2 |
AISI 316 Strain Hardened |
95,000 80,000 65,000 50,000 |
110,000 100,000 95,000 90,000 |
|||
| B8T | ASTM A193 Grade B8T Class 2 |
AISI 321 Strain Hardened |
100,000 80,000 65,000 50,000 |
125,000 115,000 105,000 100,000 |
|||
| L7 | ASTM A320 Grade L7 |
Bolts, Screws, Studs for Low-Temperature Service. Quenched and tempered. |
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 Class 1 |
Bolts, Screws, Studs for Low-Temperature Service. Class 1: Carbide solution treated. Class 2: Carbide solution treated and strain hardened. |
AISI 304 | 1/4 and larger | – | 30,000 | 75,000 |
| B8C | ASTM A320 Grade B8C Class 1 |
AISI 347 | |||||
| B8T | ASTM A320 Grade B8T Class 1 |
AISI 321 | |||||
| B8F | ASTM A320 Grade B8F Class 1 |
AISI 303 or 303Se |
|||||
| B8M | ASTM A320 Grade B8M Class 1 |
AISI 316 | |||||
| B8 | ASTM A320 Grade B8 Class 2 |
AISI 304 | 1/4 thru 3/4 Over 3/4 thru 1 Over 1 thru 1-1/4 Over 1-1/4 thru 1-1/2 |
– – – – |
100,000 80,000 65,000 50,000 |
125,000 115,000 105,00 100,00 |
|
| B8C | ASTM A320 Grade B8C Class 2 |
AISI 347 | |||||
| B8F | ASTM A320 Grade B8F Class 2 |
AISI 303 or 303Se |
|||||
| B8T | ASTM A320 Grade B8T Class 2 |
AISI 321 | |||||
| B8M | ASTM A320 Grade B8M Class 2 |
AISI 316 | 1/4 thru 3/4 Over 3/4 thru 1 Over 1 thru 1-1/4 Over 1-1/4 thru 1-1/2 |
– – – – |
95,000 80,000 65,000 50,000 |
110,000 100,000 95,000 90,000 |
|
| Three Radial Lines 120 degrees apart |
SAE J429 Grade 5 |
Bolts, Screws, Studs |
Medium Carbon Steel, Quenched and Tempered | 1/4 thru 1 Over 1 to 1-1/2 |
85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
| ASTM A449 | 1/4 thru 1 Over 1 to 1-1/2 Over 1-1/2 thru 3 |
85,000 74,000 55,000 |
92,000 81,000 58,000 |
120,000 105,000 90,000 |
|||
| Three Radial Lines 90 degrees apart |
SAE J429 Grade 5.1 |
Sems | Low or Medium Carbon Steel, Quenched and Tempered | No. 6 thru 3/8 |
85,000 | – | 120,000 |
| Three Radial Lines 60 degrees apart |
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 |
| – | ASTM A325 Type 2 (Withdrawn) |
Low Carbon Martensitic Steel, Quenched and Tempered | – | – | – | – | |
| 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 |
|
| BD | ASTM A354 Grade BD |
Bolts, Studs |
Alloy Steel, Quenched and Tempered | 1/4 thru 2-1/2 2-3/4 thru 4 |
120,000 105,000 |
130,000 115,000 |
150,000 140,000 |
| BC | ASTM A354 Grade BC |
105,000 95,000 |
109,000 99,000 |
125,000 115,000 |
|||
| Five Radial Lines |
SAE J429 Grade 7 |
Bolts, Screws, |
Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 thru 1-1/2 | 105,000 | 115,000 | 133,000 |
| Six Radial Lines 60 degrees apart |
SAE J429 Grade 8 |
Bolts, Screws, Studs |
Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 thru 1-1/2 | 120,000 | 130,000 | 150,000 |
| No Grade Mark |
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 Grade Mark |
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 Grade Mark |
ISO R898 Class 5.8 |
55,000 | 57,000 | 74,000 | |||
| 8.8
or 88 |
ISO R898 Class 8.8 |
Alloy Steel, Quenched and Tempered | 85,000 | 92,000 | 120,000 | ||
| 10.9
or 109 |
ISO R898 Class 10.9 |
120,000 | 130,000 | 150,000 | |||
FASTENER IDENTIFICATION MARKING – NUTS
| Grade Identification Marking |
Specification | Material | Nominal Size In. |
Proof Load Stress ksi |
Hardness Rockwell |
See Note |
|
|---|---|---|---|---|---|---|---|
| Min | Max | ||||||
| No Mark | ASTM A563 – Grade 0 Hex |
Carbon Steel | 1/4 thru 1-1/2 | 69 | B55 | C32 | 3,4 |
| ASTM A563 – Grade A Hex |
Carbon Steel | 1/4 thru 1-1/2 | 90 | B68 | C32 | 3,4 | |
| ASTM A563 – Grade B Hex |
Carbon Steel | 1/4 thru 1 | 120 | B69 | C32 | 3,4 | |
| over 1 thru 1-1/2 | 105 | ||||||
| Three circumferential marks 120 degrees apart |
ASTM A563 – Grade C Heavy Hex |
Carbon Steel May be Quenched and Tampered |
1/4 thru 4 | 144 | B78 | C38 | 5 |
|
Three circumferential marks |
ASTM A563 – Grade C3 Heavy Hex |
Atmospheric Corrosion Resistant Steel May be Quenched and Tampered |
1/4 thru 4 | 144 | B78 | C38 | 5,9 |
| D | ASTM A563 – Grade D Heavy Hex |
Carbon Steel May be Quenched and Tampered |
1/4 thru 4 | 150 | B84 | C38 | 6 |
| DH | ASTM A563 – Grade DH Heavy Hex |
Carbon Steel Quenched and Tampered |
1/4 thru 4 | 175 | C24 | C38 | 6 |
| DH3 | ASTM A563 – Grade DH3 |
Atmospheric Corrosion Resistant Steel, Quenched and Tampered |
1/4 thru 4 | 175 | C24 | C38 | 5,9 |
| 1 | ASTM A194 – Grade 1 |
Carbon Steel | 1/4 thru 4 | 120 for Hex Nuts, 130 for Heavy Hex Nuts |
B70 | – | 7 |
| 2 | ASTM A194 – Grade 2 |
Medium Carbon Steel |
1/4 thru 4 | 135 Hex, 150 Heavy Hex |
159 BHN | 352 BHN | 7,8 |
| 2H | ASTM A194 – Grade 2H |
Medium Carbon Steel, Quenched and Tempered |
1/4 thru 4 | 150 Hex, 175 Heavy Hex |
C24 | C38 | 7 |
| 2HM | ASTM A194 – Grade 2HM |
Medium Carbon Steel, Quenched and Tempered |
1/4 thru 4 | 135 Hex, 150 eavy Hex |
159 BHN | 237 BHN | 7,8 |
| 4 | ASTM A194 – Grade 4 |
Medium Carbon Alloy Steel, Quenched and Tempered |
1/4 thru 4 | 150 Hex, 175 Heavy Hex |
C24 | C38 | 7 |
| 7 | ASTM A194 – Grade 7 |
Medium Carbon Alloy Steel, Quenched and Tempered |
1/4 thru 4 | 150 Hex, 175 Heavy Hex |
C24 | C38 | 7 |
| 7M | ASTM A194 – Grade 7M |
Medium Carbon Alloy Steel, Quenched and Tempered |
1/4 thru 4 | 135 Hex, 150 Heavy Hex | 159 BHN | 237 BHN | 7 |
| See Note 1,2 | See Note 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.
MECHANICAL REQUIREMENTS FOR STAINLESS STEEL & NON-FERROUS FASTENERS
| Grade | General Descpription of Material |
Bolts, Screws and Studs | Nuts | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Full Size Bolts, Screws, Studs |
Machine Test Sprecimens of Bolts, Screws, Studs |
Hardness Rockwell |
Proof Load Stress |
Hardness Rockwell |
|||||
| Yield Strength |
Tensile Strength |
Yield Strength |
Tensile Strength |
Elong- ation |
|||||
| Min psi | Min psi | Min psi | Min psi | % Min. | Min | psi | Min | ||
| 303A | Austenitic Stainless Steel- Sol. Annealed |
30,000 | 75,000 | 30,000 | 75,000 | 20 | B75 | 75,000 | B75 |
| 304-A | Austenitic Stainless Steel- Sol. Annealed |
30,000 | 75,000 | 30,000 | 75,000 | 20 | B75 | 75,000 | B75 |
| 304 | Austenitic Stainless Steel- Cold Worked |
50,000 | 90,000 | 45,000 | 85,000 | 20 | B85 | 90,000 | B85 |
| 304-SH | Austenitic Stainless Steel- Strain Hardened |
See Note 11 |
See Note 11 |
See Note 11 |
See Note 11 |
15 | C25 | See Note 11 |
C20 |
| 305-A | Austenitic Stainless Steel- Sol. Annealed |
30,000 | 75,000 | 30,000 | 75,000 | 20 | B70 | 75,000 | B70 |
| 305 | Austenitic Stainless Steel- Cold Worked |
50,000 | 90,000 | 45,000 | 85,000 | 20 | B85 | 90,000 | B85 |
| 305-SH | Austenitic Stainless Steel- Strain Hardened |
See Note 11 |
See Note 11 |
See Note 11 |
See Note 11 |
15 | C25 | See Note 11 |
C20 |
| 316-A | Austenitic Stainless Steel- Sol. Annealed |
30,000 | 75,000 | 30,000 | 75,000 | 20 | B70 | 75,000 | B70 |
| 316 | Austenitic Stainless Steel- Cold Worked |
50,000 | 90,000 | 45,000 | 85,000 | 20 | B85 | 90,000 | B85 |
| 316-SH | Austenitic Stainless Steel- Strain Hardened |
See Note 11 |
See Note 11 |
See Note 11 |
See Note 11 |
15 | C25 | See Note 11 |
C20 |
| XM7-A | Austenitic Stainless Steel- Sol. Annealed |
30,000 | 75,000 | 30,000 | 75,000 | 20 | B70 | 75,000 | B70 |
| XM7 | Austenitic Stainless Steel- Cold Worked |
50,000 | 90,000 | 45,000 | 85,000 | 20 | B85 | 90,000 | B85 |
| 384-A | Austenitic Stainless Steel- Sol. Annealed |
30,000 | 75,000 | 30,000 | 75,000 | 20 | B70 | 75,000 | B70 |
| 384 | Austenitic Stainless Steel- Cold Worked |
50,000 | 90,000 | 45,000 | 85,000 | 20 | B85 | 90,000 | B85 |
| 410-H | Martensitic Stainless Steel- Hardened and Tempered |
95,000 | 125,000 | 95,000 | 125,000 | 20 | C22 | 125,000 | C22 |
| 410-HT | Martensitic Stainless Steel- Hardened and Tempered |
135,000 | 180,000 | 135,000 | 180,000 | 12 | C36 | 180,000 | C36 |
| 416-H | Martensitic Stainless Steel- Hardened and Tempered |
95,000 | 125,000 | 95,000 | 125,000 | 20 | C22 | 125,000 | C22 |
| 416-HT | Martensitic Stainless Steel- Hardened and Tempered |
135,000 | 180,000 | 135,000 | 180,000 | 12 | C36 | 180,000 | C36 |
| 430 | Ferritic Stainless Steel |
40,000 | 70,000 | 40,000 | 70,000 | 20 | B75 | 70,000 | B75 |
| 464-HF | Naval Brass | 15,000 | 52,000 | 14,000 | 50,000 | 25 | B56 | 52,000 | B56 |
| 464 | Naval Brass | 27,000 | 60,000 | 25,000 | 57,000 | 25 | B65 | 60,000 | B65 |
| 462 | Naval Brass | 27,000 | 52,000 | 24,000 | 50,000 | 20 | B65 | 52,000 | B65 |
| 642 | Aluminum Bronze | 35,000 | 72,000 | 35,000 | 72,000 | 15 | B75 | 72,000 | B75 |
| 630 | Aluminum Bronze | 50,000 | 105,000 | 50,000 | 105,000 | 10 | B90 | 105,000 | B90 |
| 614 | Aluminum Bronze | 40,000 | 75,000 | 40,000 | 75,000 | 30 | B70 | 75,000 | B70 |
| 510 | Phosphor Bronze | 35,000 | 60,000 | 35,000 | 60,000 | 15 | B60 | 60,000 | B60 |
| 675 | Manganese Bronze | 22,000 | 55,000 | 22,000 | 55,000 | 20 | B60 | 55,000 | B60 |
| 655-HF | Silicon Bronze | 20,000 | 52,000 | 18,500 | 50,000 | 20 | B60 | 52,000 | B60 |
| 655 | Silicon Bronze | 38,000 | 70,000 | 36,000 | 68,000 | 15 | B75 | 70,000 | B75 |
| 651 | Silicon Bronze | 45,000 | 75,000 | 42,500 | 72,000 | 8 | B75 | 75,000 | B75 |
| 661 | Silicon Bronze | 38,000 | 70,000 | 38,000 | 70,000 | 15 | B75 | 70,000 | B75 |
| NICU- A-HF |
Nickel-Copper Alloy A |
25,000 | 70,000 | 25,000 | 70,000 | 20 | B70 | 70,000 | B70 |
| NICU-A | Nickel-Copper Alloy A |
40,000 | 80,000 | 40,000 | 80,000 | 20 | B80 | 80,000 | B80 |
| NICU-B | Nickel-Copper Alloy B |
40,000 | 80,000 | 40,000 | 80,000 | 20 | B80 | 80,000 | B80 |
| NICU-K(7) | Nickel-Copper Aluminum Alloy |
90,000 | 130,000 | 90,000 | 130,000 | 20 | C24 | 130,000 | C24 |
| 2024-T4 | Aluminum Alloy | 40,000 | 55,000 | 40,000 | 55,000 | 14 | B70 | 55,000 | B70 |
| 6061-T6 | Aluminum Alloy | 35,000 | 42,000 | 35,000 | 42,000 | 12 | B50 | 42,000 | B50 |
Note 11:
Austenitic stainless steel, strain hardened bolts, screws, studs, and nuts shall have the following strength properties.
| Product Size | Bolts, Screws, Studs | Nuts | |||
|---|---|---|---|---|---|
| Tested Full Size | Machine Test Specimens | Proof Load Stress |
|||
| Yield Strength |
Tensile Strength |
Yield Strength |
Tensile Strength |
||
| in. | min. psi | min. psi | min. psi | min. psi | psi |
| to 5/8 in. | 100,000 | 125,000 | 90,000 | 115,000 | 125,000 |
| over 5/8 to 1 in. | 70,000 | 105,000 | 65,000 | 100,000 | 105,000 |
| over 1 to 1-1/2 in. | 50,000 | 90,000 | 45,000 | 85,000 | 90,000 |
