-
Call Us On
+91 97695 84950
-
Mail Us @
[email protected]
Heavy Hex Nuts
Heavy Hex Nuts are engineered to withstand extreme tension and vibration. Their wider dimensions across the flats and increased thickness distribute the load over a larger area, reducing the chance of nut deformation and providing exceptional strength in high-load assemblies.
Moksh Tubes & Fittings LLP is a leading manufacturer, supplier, and exporter of Heavy Hex Nuts in India, specializing in ASTM A194 Grade 2H, Grade 8, and Grade 8M. Our products are widely supplied to Indian petrochemical projects and Gulf / GCC countries including UAE, Saudi Arabia, Qatar, Oman, and Kuwait.
Manufactured via hot and cold forging processes, our nuts feature precision-tapped threads that ensure smooth engagement with stud bolts, preventing galling and providing a permanent, leak-proof seal for high-pressure flanges.
Download Heavy Hex Nuts Datasheet
Get the complete Heavy Hex Nuts datasheet with chemical composition, mechanical properties, heat treatment details, and applications. Enter your email to receive the PDF instantly.
We respect your privacy. Your email will only be used to send the datasheet.
SPECIFICATIONS
| Category | Details |
|---|---|
| Material | Carbon/Alloy Steel, Stainless Steel, Duplex & Super Duplex Steel, Nickel Alloys, Inconel, Monel, Titanium |
| Size Range | 1/4" to 4" (Imperial) | M6 to M100 (Metric) |
| Thread Type | UNC, UNF, Metric Coarse, Metric Fine (8-UN standard for > 1") |
| Finishes | PTFE (Teflon), Zinc Plated, Hot Dip Galvanized (HDG), Black Oxide, Cadmium, Plain |
| Standards | ASTM A194, ASTM A563, ASME B18.2.2, DIN 6915, ISO 4032 |
| Mating Fasteners | ASTM A193 B7/B8 Studs, ASTM A325/A490 Structural Bolts |
Dimensional Data
Heavy Hex Nut Dimensions (ASME B18.2.2 - Imperial)
| Nominal Size | Threads per Inch (UNC) | Width Across Flats (F) (inches) | Thickness / Height (H) (inches) |
|---|---|---|---|
| 1/2" | 13 | 7/8 | 31/64 |
| 5/8" | 11 | 1-1/16 | 39/64 |
| 3/4" | 10 | 1-1/4 | 47/64 |
| 7/8" | 9 | 1-7/16 | 55/64 |
| 1" | 8 | 1-5/8 | 63/64 |
| 1-1/8" | 8 (8-UN) | 1-13/16 | 1-7/64 |
| 1-1/4" | 8 (8-UN) | 2 | 1-7/32 |
| 1-1/2" | 8 (8-UN) | 2-3/8 | 1-15/32 |
| 2" | 8 (8-UN) | 3-1/8 | 1-31/32 |
*Above 1" nominal size, the 8-UN (8 threads per inch) thread series is standard for ASTM A194 Grade 2H heavy hex nuts used in high-pressure flanges.
Available Grades & Materials
ASTM A194 – Standard Specification for Carbon/Alloy/Stainless Nuts:
| Material Grade | Common Application |
|---|---|
| ASTM A194 Grade 2H (Carbon Steel) | High-pressure, high-temperature service (Paired with B7 studs) |
| ASTM A194 Grade 2HM | Sour gas / NACE MR0175 compliant (Paired with B7M studs) |
| ASTM A194 Grade 8 (SS304) | Corrosive environments, general stainless applications (Paired with B8 studs) |
| ASTM A194 Grade 8M (SS316) | Marine environments, chemical processing (Paired with B8M studs) |
| ASTM A194 Grade 4 / 7 | Extreme high-temperature service / Sub-zero applications |
GRADE 2H (CARBON STEEL)
STAINLESS STEEL (GRADE 8/8M)
DUPLEX & SUPER DUPLEX
NICKEL ALLOYS
HAYNES SUPERALLOYS
TITANIUM ALLOYS
Applications of Heavy Hex Nuts
Heavy Hex Nuts are the standard for high-stress connections across major industries:
Pipeline Flanges
- Securing raised face (RF) and ring-type joint (RTJ) flanges under high pressure.
Structural Steel
- Used with A325 and A490 structural bolts for bridge and building construction.
Oil & Gas Refineries
- Fastening pressure vessels, heat exchangers, and high-temperature manifolds.
Power Generation
- Securing steam turbines, boilers, and high-pressure steam lines.
Offshore Platforms
- PTFE coated Grade 2H and 8M nuts are used to resist severe marine corrosion.
Water Works
- Large diameter valves and pump casings in municipal water treatment plants.
Mechanical Properties – ASTM A194
| Grade | Proof Load Stress (MPa) | Hardness (Brinell HBW) | Hardness (Rockwell) |
|---|---|---|---|
| Grade 2H | 1205 (for up to 1-1/2") | 248 - 352 | 24 - 38 HRC |
| Grade 2HM | 1035 | 159 - 235 | 99 HRB - 22 HRC |
| Grade 8 / 8M (Carbide Solution Treated) | 550 | 126 - 300 | 60 HRB - 32 HRC |
*Grade 2H requires high proof load stress for heavy industrial use, while Grade 8/8M prioritizes corrosion resistance.
Tolerances & Quality Standards
- Thread Tolerance: Unified Inch threads conform to ASME B1.1 Class 2B fit; Metric threads to ISO 965 Class 6H.
- Dimensional Tolerance: Strictly adheres to ASME B18.2.2 ensuring proper wrench fitment and bearing surface flatness.
- Overtapping for Galvanizing: Nuts that are Hot-Dip Galvanized (HDG) are tapped slightly oversize (overtapped) to accommodate the thickness of the zinc coating on the mating stud bolt.
Why Choose Moksh Tubes?
Frequently Asked Questions (FAQ)
Why use a Heavy Hex Nut instead of a Standard Hex Nut?
Heavy hex nuts have a larger width across the flats and are slightly thicker. This provides a greater bearing surface against the flange face, preventing the nut from pulling through or deforming under the extreme tension required in high-pressure piping systems.
What stud bolt should be used with an ASTM A194 Grade 2H heavy hex nut?
Grade 2H nuts are most commonly paired with ASTM A193 Grade B7 stud bolts for high-temperature and high-pressure service.
What does "8-UN" mean in relation to heavy hex nuts?
8-UN stands for 8 threads per inch. For heavy hex nuts and studs larger than 1 inch in diameter, the 8-UN thread series is standard (instead of UNC) to ensure consistent thread engagement and strength across larger sizes.
Are Heavy Hex Nuts reusable after being tightened in a flange?
In critical high-pressure and high-temperature applications, it is generally recommended to replace heavy hex nuts and studs once they have been fully torqued and removed, as the threads may have yielded or deformed slightly.
Contact Us
For further information, quotes, or custom manufacturing of Heavy Hex Nuts, Moksh Tubes & Fittings LLP is your dependable partner for industrial flanged fastening solutions.
Get in Touch