ASTM A194 Grade 2H Heavy Hex Nuts
ASTM A194 Grade 2H Heavy Hex Nuts are industrial-grade nuts commonly used with ASTM A193 B7 stud bolts to form complete bolting assemblies for flange connections. Unlike standard hex nuts used for general fastening purposes, Grade 2H heavy hex nuts are manufactured with a heavier pattern, providing increased nut thickness and larger bearing surfaces for applications requiring stable tightening and reliable joint performance.
The heavy hex design allows these nuts to better match high strength stud bolts and provides improved contact between the nut, bolt and connected components. During installation, the larger wrenching dimensions allow proper tightening torque to be applied, helping maintain consistent clamping force in bolted flange joints. This makes ASTM A194 Grade 2H nuts widely selected for industrial equipment where connection reliability is important. ASTM A194 Grade 2H Heavy Hex Nuts are typically paired with ASTM A193 B7 stud bolts in applications such as oil and gas pipelines, petrochemical facilities, pressure vessels, power generation equipment and other industrial piping systems. Available in different sizes, thread configurations and surface finishes, these nuts can be supplied according to project requirements and assembly specifications.
Specification:
1. Diameter: The diameter of an A194 heavy hex nut refers to the size of the nut’s threaded hole. It is typically specified using a measurement like 1/2″, 5/8″, or 3/4″, indicating the inner diameter.
2. Grade: The grade 2H of an A194 heavy hex nut signifies its strength and material properties.
3. Material: These nuts are commonly made from carbon steel or alloy steel, depending on the grade, to meet specific strength and performance requirements.
4. Surface Treatment: Surface treatment refers to any coating or finish applied to the outer surface of the nuts
| Product name | A194 Grade 2H Heavy Hex Nuts |
|---|---|
| Standard | ASTM A194 |
| Diameter | 1/4"-4" |
| Thread: | UNC/UNF/8UN |
| Materials: | C45 STEEL |
| Grade: | 2H |
| Proof Load Stress: | 175KSI |
| Hardness: | C24-C38 |
| Marking: | 2H+Customer Brand |
| Dimension: | ASME B 18.2.2, ASME B 18.2.4.6M |
| Surface treatment: | Black Oxide Coating/Zinc Plating (Electroplating)/Hot-Dip Galvanizing/Mechanical Galvanizing/Dacromet Coating/Painting or Powder Coating |
| Application Industry | Construction/Bridges/Industrial Structures/Equipment and Machinery/Infrastructure |
Chemical Composition for A194 2H Heavy Hex Nuts:
| Chemical Elements | Composition |
|---|---|
| Carbon | 0.15 Min |
| Manganese | 1.00 Max |
| Phosphorus | 0.04 Max |
| Sulfur | 0.05 Max |
| Silicon | 0.4 Max |
Proof Load:
| Norminal Size | Thread Per Inch | Proof Load,lbf (Heavy Hex) | Proof Load,lbf (Hex) |
|---|---|---|---|
| 1/4″ | 20 | 5570 | 4770 |
| 5/16″ | 18 | 9170 | 7860 |
| 3/8″ | 16 | 13560 | 11620 |
| 7/16″ | 14 | 18600 | 15940 |
| 1/2″ | 13 | 24830 | 21280 |
| 9/16″ | 12 | 31850 | 27300 |
| 5/8″ | 11 | 39550 | 33900 |
| 3/4″ | 10 | 58450 | 50100 |
| 7/8″ | 9 | 80850 | 69300 |
| 1″ | 8 | 106000 | 90900 |
| 1 1/8″ | 8 | 138200 | 118500 |
| 1 1/4″ | 8 | 175000 | 150000 |
| 1 3/8″ | 8 | 215800 | 185000 |
| 1 1/2″ | 8 | 261100 | 223800 |
Dimension Chart of ASTM A194 Gr.2H Heavy Hex Nut:
The dimension chart of ASTM A194 Grade 2H Heavy Hex Nuts provides detailed dimensional information to help customers select the correct nut size for their bolting assemblies. Compared with standard hex nuts, heavy hex nuts have their own dimensional requirements, including larger width across flats, greater thickness and heavier body dimensions. These dimensions are important for ensuring proper fit and compatibility with matching stud bolts during installation.
The following dimension chart lists the commonly used specifications of ASTM A194 Grade 2H Heavy Hex Nuts, including nominal diameter, thread size, width across flats, width across corners and nut height. The dimensions are based on applicable ASME standards and are commonly used for matching ASTM A193 B7 stud bolts in flange bolting applications. Different sizes and thread configurations of ASTM A194 Grade 2H Heavy Hex Nuts can be supplied according to project requirements. Selecting the correct nut dimensions helps ensure proper engagement with the stud bolt threads, suitable tightening conditions and reliable assembly performance for industrial bolting systems.
| Mon | 3/8 | 1/2 | 9/16 | 5/8 | 3/4 | 7/8 | 1 | 1-1/8 | 1-1/4 | 1-3/8 | 1-1/2 | 1-5/8 | 1-3/4 | 1-7/8 | 2 | 2-1/4 | 2-1/2 | 2-3/4 | 3 | 3-1/4 | 3-1/2 | 3-3/4 | 4 |
| P | 16|24|32 | 13|20|28 | 12|18|24 | 11|18|24 | 10|16|20 | 9|14|20 | 8|12|20 | 7|12|18 | 7|12|18 | 6|12|18 | 6|12|18 | 6|12|18 | 5|8|12 | 6 | 4.5 | 4.5 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| s min | 0.669 | 0.85 | 0.909 | 1.031 | 1.212 | 1.394 | 1.575 | 1.756 | 1.938 | 2.119 | 2.3 | 2.481 | 2.662 | 2.844 | 3.025 | 3.388 | 3.75 | 4.112 | 4.475 | 4.838 | 5.2 | 5.562 | 5.925 |
| s max | 0.688 | 0.875 | 0.938 | 1.062 | 1.25 | 1.438 | 1.625 | 1.812 | 2 | 2.188 | 2.375 | 2.562 | 2.75 | 2.938 | 3.125 | 3.5 | 3.875 | 4.25 | 4.625 | 5 | 5.375 | 5.75 | 6.125 |
| e min | 0.763 | 0.969 | 1.037 | 1.175 | 1.382 | 1.589 | 1.796 | 2.002 | 2.209 | 2.416 | 2.622 | 2.828 | 3.035 | 3.242 | 3.449 | 3.862 | 4.275 | 4.688 | 5.102 | 5.515 | 5.928 | 6.341 | 6.755 |
| e max | 0.794 | 1.01 | 1.083 | 1.227 | 1.443 | 1.66 | 1.876 | 2.093 | 2.309 | 2.526 | 2.742 | 2.959 | 3.175 | 3.392 | 3.608 | 4.041 | 4.474 | 4.907 | 5.34 | 5.774 | 6.207 | 6.64 | 7.073 |
| k min | 0.341 | 0.464 | 0.526 | 0.587 | 0.71 | 0.833 | 0.956 | 1.079 | 1.187 | 1.31 | 1.433 | 1.556 | 1.679 | 1.802 | 1.925 | 2.155 | 2.401 | 2.647 | 2.893 | 3.124 | 3.37 | 3.616 | 3.862 |
| k max | 0.377 | 0.504 | 0.568 | 0.631 | 0.758 | 0.885 | 1.012 | 1.138 | 1.251 | 1.378 | 1.505 | 1.632 | 1.759 | 1.886 | 2.013 | 2.251 | 2.505 | 2.759 | 3.013 | 3.252 | 3.506 | 3.76 | 4.014 |
Application of A194 Heavy Hex Nuts:
ASTM A194 Grade 2H nuts are used with high-strength bolts and studs in high-pressure and high-temperature bolted connections. They are commonly selected for equipment where the fastening system must maintain mechanical integrity under demanding pressure, temperature, and service conditions.
Pressure Vessels and Process Equipment
Grade 2H nuts are commonly used for pressure vessels, heat exchangers, boilers, flanges, and process equipment. They are typically paired with ASTM A193 alloy steel studs or bolts to secure flanged and pressure-containing connections.
Piping and Flanged Connections
These nuts are widely used in industrial piping systems, pipe flanges, valves, pumps, and pressure-rated connections where high-strength bolting is required. The nut-and-stud assembly helps maintain the clamping force needed to keep flanged joints securely assembled.
Oil, Gas and Petrochemical Equipment
ASTM A194 Grade 2H nuts are also used in oil and gas facilities, refineries, petrochemical plants, power-generation equipment, and other process installations where high-pressure or elevated-temperature bolted connections are encountered.