Grade 8M SS Heavy Hex Nut
Grade 8M SS Heavy Hex Nut
Manufacturers:
ASTM A194 Grade 8M heavy hex nuts are manufactured from AISI 316 grade stainless steel and tested to meet ASTM A194 Grade 8M. Dimensional specifications are governed by ASME B18.2.2. Grade markings for A194 Grade 8M heavy hex nuts consists of the number/letter combination of 8M. Grade 8M stainless steel heavy hex nuts are intended for use in high-pressure and/or high-temperature service with ASTM A193 and A320 bolting of similar material, such as B8M and B8M Class 2. Heavy hex nuts provide increased bearing surface area over finished nuts.
Products
Governing Standards
| 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. |
Grade 8M Stainless Steel Material Marking
Chemical Properties
| Per ASTM A194/A194M-16 | |||||||||
| Grade | Material | Carbon | Manganese | Phosphorus | Sulfur (1) | Silicon | Chromium | Nickel | Molybdenum |
| % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % 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 |
- 1. Because of the degree to which sulfur segregates, product analysis for sulfur over 0.060 % max is not technologically appropriate.
Dimensional Specifications
| Per ASME B18.2.2-2015 | |||||||||||
| Nominal Diameter | UNC | UN8 | F | G | H | ||||||
| Width Across Flats | Width Across Corners | Thickness | |||||||||
| Basic | Max | Min | Max | Min | Basic | Max | Min | ||||
| 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 |
- All dimensions are in inches.
Mechanical Properties
| Stainless AISI 316 | Per ASTM A194/A194M-16 | |
| Diameter | Proof Load Stress | Core Hardness |
| Min psi | Rockwell | |
| 1/4" thru 4" | 80,000 | C32 max |