ASTM A194 Grade 8M Heavy Hex Nuts
ASTM A194 Grade 8M heavy hex nuts are stainless steel nuts designed for high-temperature and corrosion-resistant bolting applications. RAM Threading supplies 8M heavy hex nuts commonly used in pressure service and paired with ASTM A193 B8M stud bolts to provide reliable performance in demanding industrial environments.
Per ASTM A193/A193M-16
| Diameter | Proof Load Stress (Min psi) | Core Hardness (Rockwell) |
|---|---|---|
| 1/4″ thru 4″ | 80,000 | C32 max |
Per ASTM A193/A193M-16
| Grade | Material | Carbon % by weight |
Manganese % by weight |
Phosphorus % by weight |
Sulfur (1) % by weight |
Silicon % by weight |
Chromium % by weight |
Nickel % by weight |
Molybdenum % by weight |
|---|---|---|---|---|---|---|---|---|---|
| 8M | Type 316 Stainless Steel | 0.08 max | 2.00 max | 0.045 max | 0.030 max | 1.00 max | 16.0–18.0 | 10.0–14.0 | 2.00–3.00 |
ASTM A194
This specification covers a variety of carbon, alloy, and martensitic stainless steel nuts in the size range
1⁄4 through 4 in. and metric M6 through M100 nominal. It also covers austenitic stainless steel nuts in the
size range 1⁄4 in. and M6 nominal and above. These nuts are intended for high-pressure or high-temperature
service, or both. Grade substitutions without the purchaser’s permission are not allowed.
ASME B18.2.2
Covers the complete general and dimensional data for the various types of inch series square and hex nuts,
including machine screw nuts and coupling nuts.
ASME B1.1 UNC & UNF Class 2B
Specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads.
| Nominal Diameter | UNC | UN8 | F Width Across Flats |
G Width Across Corners |
H Thickness |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basic | Max | Min | Max | Min | Basic | Max | Min | ||||||
| Fraction | Decimal | ||||||||||||
| 1/4 | 0.250 | 20 | 1/2 | 0.500 | 0.488 | 0.577 | 0.556 | 15/64 | 0.250 | 0.218 | |||
| 5/16 | 0.313 | 18 | 9/16 | 0.562 | 0.546 | 0.650 | 0.220 | 19/64 | 0.314 | 0.280 | |||
| 3/8 | 0.375 | 16 | 11/16 | 0.688 | 0.669 | 0.794 | 0.763 | 23/64 | 0.377 | 0.341 | |||
| 7/16 | 0.438 | 14 | 3/4 | 0.750 | 0.728 | 0.866 | 0.830 | 27/64 | 0.441 | 0.403 | |||
| 1/2 | 0.500 | 13 | 7/8 | 0.875 | 0.850 | 1.010 | 0.990 | 31/64 | 0.504 | 0.464 | |||
| 9/16 | 0.563 | 12 | 15/16 | 0.938 | 0.909 | 1.083 | 1.037 | 35/64 | 0.568 | 0.526 | |||
| 5/8 | 0.625 | 11 | 1 1/16 | 1.062 | 1.031 | 1.227 | 1.175 | 39/64 | 0.631 | 0.587 | |||
| 3/4 | 0.750 | 10 | 1 1/4 | 0.250 | 1.212 | 1.443 | 1.382 | 47/64 | 0.758 | 0.710 | |||
| 7/8 | 0.875 | 9 | 1 7/16 | 1.438 | 1.394 | 1.660 | 1.589 | 55/64 | 0.885 | 0.833 | |||
| 1 | 1.000 | 8 | 1 5/8 | 1.625 | 1.575 | 1.876 | 1.796 | 63/64 | 1.012 | 0.956 | |||
| 1 1/8 | 1.125 | 7 | 8 | 1 13/16 | 1.812 | 1.756 | 2.093 | 2.002 | 1 7/64 | 1.139 | 1.079 | ||
| 1 1/4 | 1.250 | 7 | 8 | 2 | 2.000 | 1.380 | 2.309 | 2.209 | 1 7/32 | 1.251 | 1.187 | ||
| 1 3/8 | 1.375 | 6 | 8 | 2 3/16 | 2.188 | 2.119 | 2.526 | 2.416 | 1 11/32 | 1.378 | 1.310 | ||
| 1 1/2 | 1.500 | 6 | 8 | 2 3/8 | 2.375 | 2.300 | 2.742 | 2.622 | 1 15/32 | 1.505 | 1.433 | ||
| 1 5/8 | 1.625 | 5 1/2 | 8 | 2 9/16 | 2.562 | 2.481 | 2.959 | 2.828 | 1 19/32 | 1.632 | 1.556 | ||
| 1 3/4 | 1.750 | 5 | 8 | 2 3/4 | 2.750 | 2.662 | 3.175 | 3.035 | 1 23/32 | 1.759 | 1.679 | ||
| 1 7/8 | 1.875 | 5 | 8 | 2 15/16 | 2.938 | 2.844 | 3.392 | 3.242 | 1 27/32 | 1.886 | 1.802 | ||
| 2 | 2.000 | 4 1/2 | 8 | 3 1/8 | 3.125 | 3.025 | 3.608 | 3.449 | 1 31/32 | 2.013 | 1.925 | ||
| 2 1/4 | 2.250 | 4 1/2 | 8 | 3 1/2 | 3.500 | 3.388 | 4.041 | 3.862 | 2 13/64 | 2.251 | 2.155 | ||
| 2 1/2 | 2.500 | 4 | 8 | 3 7/8 | 3.875 | 3.750 | 4.474 | 4.275 | 2 29/64 | 2.505 | 2.401 | ||
| 2 3/4 | 2.750 | 4 | 8 | 4 1/4 | 4.250 | 4.112 | 4.907 | 4.688 | 2 45/64 | 2.759 | 2.647 | ||
| 3 | 3.000 | 4 | 8 | 4 5/8 | 4.625 | 4.475 | 5.340 | 5.102 | 2 61/64 | 3.013 | 2.893 | ||
| 3 1/4 | 3.250 | 4 | 8 | 5 | 5.000 | 4.838 | 5.774 | 5.515 | 3 3/16 | 3.252 | 3.124 | ||
| 3 1/2 | 3.500 | 4 | 8 | 5 3/8 | 5.375 | 5.200 | 6.207 | 5.928 | 3 7/16 | 3.506 | 3.370 | ||
| 3 3/4 | 3.750 | 4 | 8 | 5 3/4 | 5.750 | 5.562 | 5.562 | 6.341 | 3 11/16 | 3.670 | 3.616 | ||
| 4 | 4.000 | 4 | 8 | 6 1/8 | 6.125 | 5.925 | 5.925 | 6.755 | 3 15/16 | 4.014 | 3.862 | ||