ASTM 193/194/A320 Specifications
ASTM 193/194/A320 Specifications
ASTM 193 GRADES
| B7 | Alloy steel, AISI 4140/4142 quenched and tempered |
| B8 | Class 1 Stainless steel, AISI 304, carbide solution treated. |
| B8M | Class 1 Stainless steel, AISI 316, carbide solution treated. |
| B8 | Class 2 Stainless steel, AISI 304, carbide solution treated, strain hardened |
| B8M | Class 2 Stainless steel, AISI 316, carbide solution treated, strain hardened |
MECHANICAL PROPERTIES
| Grade | Size | Tensile ksi, min | Yield, ksi, min | Elong, %, min | RA % min |
| B7 | Up to 2-1/2 | 125 | 105 | 16 | 50 |
| 2-5/8 - 4 | 115 | 95 | 16 | 50 | |
| 4-1/8 - 7 | 100 | 75 | 18 | 50 | |
| B8 Class 1 | All | 75 | 30 | 30 | 50 |
| B8M Class 1 | All | 75 | 30 | 30 | 50 |
| B8 Class 2 | Up to 3/4 | 125 | 100 | 12 | 35 |
| 7/8 - 1 | 115 | 80 | 15 | 35 | |
| 1-1/8 - 1-1/4 | 105 | 65 | 20 | 35 | |
| 1-3/8 - 1-1/2 | 100 | 50 | 28 | 45 | |
| B8M Class 2 | Up to 3/4 | 110 | 95 | 15 | 45 |
| 7/8 - 1 | 100 | 80 | 20 | 45 | |
| 1-1/8 - 1-1/4 | 95 | 65 | 25 | 45 | |
| 1-3/8 - 1-1/2 | 90 | 50 | 30 | 45 |
ASTM A 194 GRADE
Mechanical Properties
Grade Identification Markings
| Grade Identification Marking5 | Specification | Material | Nominal Size, In. | Tempering Temp. °F | Proof Load Stress, ksi | Hardness Rockwell | See Note | |
| Min | Max | |||||||
| 2 | ASTM A194 Grade 2 | Medium Carbon Steel | 1/4 - 4 | 1000 | 150 | 159 | 352 | 1,2,3 |
| 2H | ASTM A194 Grade 2H | Medium Carbon Steel, Quenched and Tempered | 1/4 - 4 | 1000 | 175 | C24 | C38 | 1,2 |
| 2HM | ASTM A194 Grade 2HM | Medium Carbon Steel, Quenched and Tempered | 1/4 - 4 | 1000 | 150 | 159 | 237 | 1,2,3 |
| 4 | ASTM A194 Grade 4 | Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 - 4 | 1100 | 175 | C24 | C38 | 1,2 |
| 7 | ASTM A194 Grade 7 | Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 - 4 | 1100 | 175 | C24 | C38 | 1,2 |
| 7M | ASTM A194 Grade 7M | Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 - 4 | 1100 | 150 | 159 | 237 | 1,2,3 |
| 8 | ASTM A194 Grade 8 | Stainless AISI 304 | 1/4 - 4 | - | 80 | 126 | 300 | 4 |
| 8M | ASTM A194 Grade 8M | Stainless AISI 316 | 1/4 - 4 | - | 80 | 126 | 300 | 4 |
ASTM 194 NUT DIMENSIONS
| Nominal Size | F | C | H | Weight | |||||
| Width Across Flats | Width Across Corners | Thickness | Per Nut | ||||||
| Basic | Max | Min | Max | Min | Basic | Max | Min | ||
| 3/8 | 11/16 | 0.688 | 0.669 | 0.794 | 0.763 | 23/64 | 0.377 | 0.341 | 0.03 |
| 1/2 | 7/8 | 0.875 | 0.850 | 1.010 | 0.969 | 31/64 | 0.504 | 0.464 | 0.07 |
| 5/8 | 1-1/16 | 1.062 | 1.031 | 1.227 | 1.175 | 39/64 | 0.631 | 0.587 | 0.12 |
| 3/4 | 1-1/4 | 1.250 | 1.212 | 1.443 | 1.382 | 47/64 | 0.758 | 0.710 | 0.20 |
| 7/8 | 1-7/16 | 1.438 | 1.394 | 1.660 | 1.589 | 55/64 | 0.885 | 0.833 | 0.30 |
| 1 | 1-5/8 | 1.625 | 1.575 | 1.876 | 1.796 | 63/64 | 1.012 | 0.956 | 0.43 |
| 1-1/8 | 1-13/16 | 1.812 | 1.756 | 2.093 | 2.002 | 1-7/64 | 1.139 | 1.079 | 0.59 |
| 1-1/4 | 2 | 2.000 | 1.938 | 2.309 | 2.209 | 1-7/32 | 1.251 | 1.187 | 0.79 |
| 1-3/8 | 2-3/16 | 2.188 | 2.119 | 2.526 | 2.416 | 1-11/32 | 1.378 | 1.310 | 1.02 |
| 1-1/2 | 2-3/8 | 2.375 | 2.300 | 2.742 | 2.622 | 1-15/32 | 1.505 | 1.433 | 1.31 |
| 1-5/8 | 2-9/16 | 2.562 | 2.481 | 2.959 | 2.828 | 1-19/32 | 1.632 | 1.556 | 1.62 |
| 1-3/4 | 2-3/4 | 2.750 | 2.662 | 3.175 | 3.035 | 1-23/32 | 1.759 | 1.679 | 2.04 |
| 1-7/8 | 2-15/16 | 2.938 | 2.844 | 3.392 | 3.242 | 1-27/32 | 1.886 | 1.802 | 2.41 |
| 2 | 3-1/8 | 3.125 | 3.025 | 3.608 | 3.449 | 1-31/32 | 2.013 | 1.925 | 2.99 |
| 2-1/4 | 3-1/2 | 3.500 | 3.388 | 4.041 | 3.862 | 2-13/64 | 2.251 | 2.155 | 4.19 |
| 2-1/2 | 3-7/8 | 3.875 | 3.750 | 4.474 | 4.275 | 2-29/64 | 2.505 | 2.401 | 5.64 |
| 2-3/4 | 4-1/4 | 4.250 | 4.112 | 4.907 | 4.688 | 2-45/64 | 2.759 | 2.647 | 7.38 |
| 3 | 4-5/8 | 4.625 | 4.475 | 5.340 | 5.102 | 2-61/64 | 3.013 | 2.893 | 9.50 |
| 3-1/4 | 5 | 5.000 | 4.838 | 5.774 | 5.515 | 3-3/16 | 3.252 | 3.124 | 11.94 |
| 3-1/2 | 5-3/8 | 5.375 | 5.200 | 6.207 | 5.928 | 3-7/16 | 3.506 | 3.370 | 15.26 |
| 3-3/4 | 5-3/4 | 5.750 | 5.562 | 6.640 | 6.341 | 3-11/16 | 3.760 | 3.616 | 18.12 |
| 4 | 6-1/8 | 6.125 | 5.925 | 7.073 | 6.755 | 3-15/16 | 4.014 | 3.862 | 21.80 |
| Dimensions per ASME B18.2.2 1987 (1999) | |||||||||
ASTM A320 Grades
L7 Alloy steel, AISI 4140/4142 Quenched and tempered
L43 Alloy steel, AISI 4340 Quenched and tempered
B8 Class 1 Stainless steel, AISI 304, carbide solution treated
B8M Class 1 Stainless steel, AISI 316, carbide solution treated
B8 Class 2 Stainless steel, AISI 304, carbide solution treated, strain hardened
B8M Class 2 Stainless steel, AISI 316, carbide solution treated, strain hardened
Mechanical Properties
| Grade | Size | Tensile, ksi, min |
Yield, ksi, min |
Charpy Impact 20-ft-lbf @ temp |
Elong, %, min |
RA, %, min |
| L7 | Up to 21/2 | 125 | 105 | -150° F | 16 | 50 |
| L43 | Up to 4 | 125 | 105 | -150° F | 16 | 50 |
| B8 Class 1 |
All | 75 | 30 | N/A | 30 | 50 |
| B8M Class 1 |
All | 75 | 30 | N/A | 30 | 50 |
| B8 Class 2 |
Up to 3/4 | 125 | 100 | N/A | 12 | 35 |
| 7/8 - 1 | 115 | 80 | N/A | 15 | 35 | |
| 11/8 - 11/4 | 105 | 65 | N/A | 20 | 35 | |
| 13/8 - 11/2 | 100 | 50 | N/A | 28 | 45 | |
| B8M Class 2 |
Up to 3/4 | 110 | 95 | N/A | 15 | 45 |
| 7/8 - 1 | 100 | 80 | N/A | 20 | 45 | |
| 11/8 - 11/4 | 95 | 65 | N/A | 25 | 45 | |
| 13/8 - 11/2 | 90 | 50 | N/A | 30 | 45 |
Recommended Nuts and Washers
| Grade | Nuts | Washers |
| L7 | A194 Grade 4 or 7 | F436 |
| L43 | A194 Grade 4 or 7 | F436 |
| B8 Class 1 | A194 Grade 8 | SS304 |
| B8M Class 1 | A194 Grade 8M | SS316 |
| B8 Class 2 | A194 Grade 8, strain hardened | SS304 |
| B8M Class 2 | A194 Grade 8M, strain hardened | SS316 |