ASTM A194 Grade 2H Heavy Hex Nuts
ASTM A194 Grade 2H heavy hex nuts are high-strength nuts commonly used in structural and flange bolting applications. RAM Threading supplies 2H heavy hex nuts designed to meet demanding industrial requirements and are frequently paired with ASTM A193 B7 stud bolts for reliable, high-performance assemblies.
Key Features
- High-strength carbon steel construction
- Heat-treated (quenched and tempered) for enhanced hardness and durability
- Designed for high-pressure and high-temperature service
- Heavy hex design for improved load distribution and strength
- Precision Class 2B threading for secure fit and engagement
- Excellent performance in demanding industrial environments
- Compatible with ASTM A193 B7 stud bolts
Applications of ASTM A194 2H Heavy Hex Nuts
ASTM A194 Grade 2H heavy hex nuts are widely used in high-pressure and high-temperature applications where strength, durability, and reliability are critical.
Common applications include:
- Oil & gas refineries
- Petrochemical and chemical processing plants
- Pressure vessels and flanged connections
- Power generation facilities
- Heat exchangers
- Industrial piping systems
Commonly Paired With B7 stud bolts
ASTM A194 Grade 2H heavy hex nuts are most commonly paired with ASTM A193 B7 stud bolts to create a high-strength, reliable bolting system. This combination is designed to handle extreme pressure and temperature conditions while maintaining secure and consistent clamping force.
By matching the mechanical properties of B7 stud bolts, Grade 2H nuts ensure proper load distribution, thread engagement, and long-term performance in critical applications.
Per ASTM A193/A193M-16
| Diameter | Proof Load Stress | Core Hardness | Tempering Temperature | |
|---|---|---|---|---|
| Min psi | Min (Rockwell C) | Max (Rockwell C) | Min | |
| 1/4″ thru 1 1/2″ | 175,000 | C24 | C35 | 850°F |
| Over 1 1/2″ | 175,000 | C35 | 850°F | |
Per ASTM A193/A193M-16
| Grade | Material | Carbon | Manganese | Phosphorus | Sulfur (1) | Silicon |
|---|---|---|---|---|---|---|
| % by weight | % by weight | % by weight | % by weight | % by weight | ||
| 2H | Carbon Steel | 0.40 min | 1.00 max | 0.040 max | 0.050 max | 0.04 max |
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 | UNF | UN8 | F | G | H | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Width Across Flats | Width Across Corners | Thickness | ||||||||||
| Basic | Max | Min | Max | Min | Basic | Max | Min | |||||
| 1/4 | 0.250 | 20 | 28 | 1/2 | 0.500 | 0.488 | 0.577 | 0.556 | 15/64 | 0.250 | 0.218 | |
| 5/16 | 0.313 | 18 | 24 | 9/16 | 0.562 | 0.546 | 0.650 | 0.620 | 19/64 | 0.314 | 0.280 | |
| 3/8 | 0.375 | 16 | 24 | 11/16 | 0.688 | 0.669 | 0.794 | 0.763 | 23/64 | 0.377 | 0.341 | |
| 7/16 | 0.438 | 14 | 20 | 3/4 | 0.750 | 0.728 | 0.866 | 0.830 | 27/64 | 0.441 | 0.403 | |
| 1/2 | 0.500 | 13 | 20 | 7/8 | 0.875 | 0.850 | 1.010 | 0.990 | 31/64 | 0.504 | 0.464 | |
| 9/16 | 0.563 | 12 | 18 | 15/16 | 0.938 | 0.909 | 1.083 | 1.037 | 35/64 | 0.568 | 0.526 | |
| 5/8 | 0.625 | 11 | 18 | 1 1/16 | 1.062 | 1.031 | 1.227 | 1.175 | 39/64 | 0.631 | 0.587 | |
| 3/4 | 0.750 | 10 | 16 | 1 1/4 | 1.250 | 1.212 | 1.443 | 1.382 | 47/64 | 0.758 | 0.710 | |
| 7/8 | 0.875 | 9 | 14 | 1 7/16 | 1.438 | 1.394 | 1.660 | 1.589 | 55/64 | 0.885 | 0.833 | |
| 1 | 1.000 | 8 | 14 | 1 5/8 | 1.625 | 1.575 | 1.876 | 1.796 | 63/64 | 1.012 | 0.956 | |
| 1 1/8 | 1.125 | 7 | 12 | 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 | 12 | 8 | 2 | 2.000 | 1.380 | 2.309 | 2.209 | 1 7/32 | 1.251 | 1.187 |
| 1 3/8 | 1.375 | 6 | 12 | 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 | 12 | 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 | 12 | 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 | 12 | 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 | 12 | 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 | 12 | 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 | 12 | 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 | 12 | 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 | 12 | 8 | 4 1/4 | 4.250 | 4.112 | 4.907 | 4.688 | 2 45/64 | 2.759 | 2.647 |
| 3 | 3.000 | 4 | 12 | 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 | 12 | 8 | 5 | 5.000 | 4.838 | 5.774 | 5.515 | 3 3/16 | 3.252 | 3.124 |
| 3 1/2 | 3.500 | 4 | 12 | 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 | 12 | 8 | 5 3/4 | 5.750 | 5.562 | 6.341 | 6.207 | 3 11/16 | 3.670 | 3.616 |
| 4 | 4.000 | 4 | 12 | 8 | 6 1/8 | 6.125 | 5.925 | 6.755 | 6.555 | 3 15/16 | 4.014 | 3.862 |
Coating & Finish Options
ASTM A194 Grade 2H heavy hex nuts are available in a variety of finishes to meet different environmental and performance requirements.
- Plain Finish: Plain 2H heavy hex nuts are supplied without coating and are commonly used in controlled or non-corrosive environments. This option provides full strength and precise thread engagement without added cost.
- Hot-Dip Galvanized: Galvanized 2H nuts offer enhanced corrosion resistance for outdoor or high-moisture environments. This finish is commonly used in structural and exposed applications.
- PTFE Coated: PTFE-coated 2H nuts provide excellent corrosion resistance and reduce friction during installation. This helps prevent galling and allows for more consistent torque, making them ideal for corrosive environments.
Plain 2H Heavy Hex Nuts
Plain ASTM A194 Grade 2H heavy hex nuts are supplied without any additional coating, making them a cost-effective and reliable option for general-purpose applications in controlled environments. This finish maintains precise thread dimensions for proper engagement with ASTM A193 B7 stud bolts, ensuring consistent performance and load distribution. Plain 2H nuts are commonly used in high-pressure and high-temperature applications where corrosion exposure is minimal.
PTFE Coated 2H Heavy Hex Nuts
PTFE-coated ASTM A194 Grade 2H heavy hex nuts are designed for use in corrosive and demanding environments where additional protection is required. The PTFE coating provides excellent resistance to chemicals, moisture, and environmental exposure while also reducing friction during installation. This helps prevent galling and allows for more consistent torque, making PTFE-coated 2H nuts ideal for oil & gas, petrochemical, and marine applications.
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