COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF ASTM A194 GRADE 2H NUTS
ASTM A194 Grade 2H is a high-strength, quenched and tempered carbon steel engineered specifically for high-temperature, high-pressure service conditions. It serves as the definitive global standard for heavy-duty nuts utilized in petrochemical refineries, power generation plants, and critical industrial fluid control systems.
Through a strictly controlled heat treatment process (quenching and tempering), Grade 2H nuts develop exceptional proof load limits and sustained hardness. This ensures they maintain structural integrity and do not strip when subjected to the extreme clamping loads exerted by high-strength alloy steel bolting, such as ASTM A193 Grade B7 studs.
■ Product Overview & Specifications
ASTM A194 Grade 2H represents the industry benchmark for high-pressure, high-temperature mating nuts. This profile combines material science classifications with standard supply ranges.
| Material Classification | Quenched and Tempered Carbon Steel Heavy Hex Nuts |
|---|---|
| UNS Designation | K04002 |
| Microstructure | Tempered Martensite |
| Magnetic State | Magnetic |
| Density | ~7.85 g/cm³ (0.284 lb/in³) |
| Size Range | Metric: M6 to M100 | Imperial: 1/4" to 4" Custom oversized nuts available upon request. |
| Thread Types | UNC, UNF, 8UN, Metric Coarse, Metric Fine |
| Strengthening Method | Quenching & Tempering (Heat Treatment) |
■ Proprietary Datasheet Download (GATED)
Access professional-grade technical data for ASTM A194 Grade 2H, including proof load limit calculations, hardness parameters, and mating bolt torque charts.
ASTM A194 Grade 2H — Complete Technical Datasheet
Contains detailed proof load thresholds up to 175 ksi, dimensional tolerances for ASME B18.2.2 heavy hex profiles, and specific dry and lubricated installation torque values for B7/2H assemblies.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
Material traceability is the backbone of safety in high-pressure systems. Every lot shipped by Ananka is accompanied by fully authenticated documentation mapping back to raw steel mill certificates.
- EN 10204 Type 3.1: Issued by our independent quality department, providing specific heat-traceable test results (actual chemical analysis, mechanical test results, hardness, and proof load).
- EN 10204 Type 3.2: For critical infrastructure or "lethal service" applications, we facilitate third-party witness testing (e.g., TUV, BV, or SGS) to provide the highest level of material assurance.
■ Chemical Composition
Grade 2H is fundamentally a medium-carbon steel. The precise control of carbon and manganese ensures high hardenability during the quenching process.
| Carbon (C) | Manganese (Mn) | Phosphorus (P) | Sulfur (S) | Silicon (Si) |
|---|---|---|---|---|
| 0.40 Min | 1.00 Max | 0.040 Max | 0.050 Max | 0.40 Max |
■ Mechanical Properties
Unlike standard nuts, Grade 2H fasteners are explicitly tested for proof load stress and hardness to guarantee they can withstand the massive tensile loads of high-strength structural bolting.
| Mechanical Property | Up to 1-1/2" Diameter | Over 1-1/2" Diameter |
|---|---|---|
| Proof Load Stress (Heavy Hex) | 175 ksi (1205 MPa) | 150 ksi (1034 MPa) |
| Proof Load Stress (Standard Hex) | 150 ksi (1034 MPa) | 120 ksi (827 MPa) |
| Hardness (Rockwell C) | 24 to 35 HRC | 24 to 35 HRC |
| Hardness (Brinell) | 248 to 327 HBW | 248 to 327 HBW |
■ Equivalent Grades & Designations
| Standard / System | Designation |
|---|---|
| ASME Standard | SA194 Grade 2H |
| Common Trade Name | A194 2H Heavy Hex Nuts |
| European Equivalent | EN 10269 (Approximate Material Match) |
■ Applications & Industries
Grade 2H nuts are mandated wherever high internal pressures and elevated temperatures demand unyielding joint integrity.
- Oil & Gas / Petrochemical: Flanged connections on high-pressure pipelines, wellheads, and heavy-duty valves.
- Power Generation: Fastening systems for steam turbines, boiler feed pumps, and high-temperature exhaust manifolds.
- Pressure Vessels: Sealing heat exchangers, chemical reactors, and distillation columns under extreme PSI.
- Water & Fluid Control: Heavy-duty industrial pumps, desalination plants, and fluid transfer systems.
■ Compatible Fastener Assemblies
Ananka Group manufactures a comprehensive range of Grade 2H nuts, engineered to be perfectly matched with our high-strength A193 bolting products.
| Nuts (A194 Gr 2H) | Mating Bolts (A193 Gr B7) | Mating Studs (A193 Gr B7) |
|---|---|---|
| Heavy Hex Nuts | Heavy Hex Bolts | Fully Threaded Studs |
| Standard Hex / Jam Nuts | Socket Head Cap Screws | Double End Studs |
| Coupling Nuts / Slotted Nuts | Flange Bolts | Tap-End Studs |
■ Standards & Specifications
Manufactured to meet the most stringent international dimensional and material codes.
- ASTM A194 / ASME SA194: Standard Specification for Carbon and Alloy Steel Nuts for Bolts for High Pressure or High Temperature Service.
- ASME B18.2.2: Dimensional standard for Square and Hex Nuts (specifically Heavy Hex profiles).
- ASME B1.1: Unified Inch Screw Threads (UNC, UNF, 8UN).
- ASME B1.13M: Metric Screw Threads (M Profile).
■ Torque & Installation Guidelines (Typical B7 / 2H Pairing)
The following torque values are approximate for A193 B7 studs mated with A194 2H heavy hex nuts. Proper lubrication is vital to achieve accurate clamping force without exceeding the material's yield point.
| Nominal Diameter | Threads Per Inch (UNC) | Target Torque — Dry (ft-lbs) | Target Torque — Lubricated (ft-lbs) |
|---|---|---|---|
| 1/2" | 13 | 90 | 65 |
| 5/8" | 11 | 180 | 130 |
| 3/4" | 10 | 320 | 230 |
| 1" | 8 | 770 | 550 |
■ Why Choose Ananka Group?
Ananka Group is a leading manufacturing-driven organization specializing in high-performance bolting packages for the global energy and infrastructure sectors.
- In-House Manufacturing: Complete production control from raw material selection and hot forging through to precision thread tapping and CNC machining.
- 100% Traceability: Heat numbers are stamped directly on the nuts (alongside the '2H' mark) for absolute supply chain transparency.
- Custom Surface Coatings: Supplied plain, hot-dip galvanized (HDG), zinc-plated, or PTFE/Xylan coated based on specific environmental and offshore project needs.
- Certifications: ISO 9001:2015, ISO 14001:2015, and strict adherence to ASME and PED 2014/68/EU quality protocols.
■ Frequently Asked Questions
1. What does "2H" stand for?
The "2" designates the base medium-carbon steel chemistry, while the "H" indicates that the nut has been subjected to a rigorous quench and temper (heat treatment) process to achieve high hardness and high proof load strength.
2. What bolts or studs are typically paired with Grade 2H nuts?
A194 Grade 2H nuts are most commonly mated with ASTM A193 Grade B7 studs and heavy hex bolts. They are also suitable for pairing with A193 B16, F3125 A325, and A490 structural bolts.
3. What is the maximum operating temperature for Grade 2H nuts?
When properly installed and lubricated, ASTM A194 Grade 2H nuts perform reliably in high-temperature environments up to approximately 427°C (800°F).
4. Can Grade 2H nuts be galvanized?
Yes. They are frequently hot-dip galvanized (HDG) or zinc-plated to resist corrosion. However, the internal threads must be properly overtapped after galvanizing the nut to accommodate the extra thickness of the zinc layer on the bolt.
5. Why are 2H nuts usually "Heavy Hex" instead of standard hex?
The "Heavy Hex" profile is slightly wider and thicker than standard hex nuts. This additional mass provides a broader bearing surface and deeper thread engagement, allowing the nut to handle massive proof loads without stripping the threads or crushing.
For project-specific technical support or to request a quote for ASTM A194 Grade 2H fasteners, please contact the Ananka Group Sales and Engineering Team at sales@anankafasteners.com or via WhatsApp at +91 86557 47687. Secure your high-pressure systems with certified components and world-class manufacturing expertise.