What Are ASTM A194 Gr 2HM Fasteners?
ASTM A194 Gr 2HM Fasteners are heat-treated carbon steel fasteners, primarily supplied as heavy hex nuts, manufactured to ASTM A194/A194M Grade 2HM requirements. They are used in high-pressure, high-temperature, and specified sour-service bolting applications where controlled hardness and dependable strength are essential. Grade 2HM nuts undergo liquid quenching, tempering, and post-machining stress relief as specified by the standard.
ASTM A194 Gr 2HM Fasteners Manufacturer
ASTM A194 Gr 2HM Fasteners are high-strength carbon steel fasteners designed for demanding bolting applications where controlled hardness and reliable mechanical performance are required. These fasteners are commonly supplied as A194 Gr 2HM Heavy Hex Nuts for use with compatible high-strength bolts and studs in pressure equipment, pipelines, refineries, petrochemical plants, and oil and gas installations.
We manufacture and supply ASTM A194 Grade 2HM Fasteners in different sizes, threads, dimensions, and finishes according to project requirements. Grade 2HM is a heat-treated variant of ASTM A194 Grade 2 designed with controlled hardness, making it particularly suitable for specified sour-service applications.
The ASTM A194/A194M specification covers carbon, alloy, and stainless steel nuts intended for high-pressure and/or high-temperature service. The current ASTM specification also requires applicable chemical, hardness, proof-load, and related testing requirements for covered nut grades.
Table of Contents
- ➤ ASTM A194 Gr 2HM Fasteners Manufacturer
- ➤ What Is ASTM A194 Grade 2HM?
- ➤ ASTM A194 Gr 2HM Fasteners Types
- ➤ ASTM A194 Gr 2HM Fasteners Specifications
- ➤ Mechanical Properties of ASTM A194 Grade 2HM Nuts
- ➤ ASTM A194 Grade 2HM Weight Chart
- ➤ ASTM A194 Grade 2HM Equivalent Grades Chart
- ➤ NACE MR0175 ASTM A194 Grade 2HM Nuts
- ➤ Manufacturing Process of ASTM A194 Gr 2HM Fasteners
- ➤ Applications of ASTM A194 Grade 2HM Fasteners
- ➤ Why Choose Us for ASTM A194 Gr 2HM Fasteners?
- ➤ Order ASTM A194 Gr 2HM Fasteners With Confidence
What Is ASTM A194 Grade 2HM?
ASTM A194 Grade 2HM is a carbon steel nut grade developed for demanding industrial bolting applications. The “H” designation identifies heat-treated nuts, while the “M” designation is associated with the specific Grade 2HM requirements.
Grade 2HM is different from standard Grade 2H because it incorporates tighter hardness control for applications where resistance to sulfide stress cracking is important. Under the applicable requirements, Grade 2HM nuts are liquid quenched and tempered, with a minimum tempering temperature of 1150°F (620°C). A final stress-relief treatment is also specified after machining, cutting, or forming operations.
For projects requiring sour-service compliance, the purchase specification should clearly identify the required edition of ASTM A194/A194M and any applicable NACE requirements.
ASTM A194 Gr 2HM Fasteners Types
We supply ASTM A194 Gr 2HM Fasteners in different configurations to meet equipment, piping, flange, and structural bolting requirements.
| Fastener Type | Description |
|---|---|
| A194 Gr 2HM Heavy Hex Nuts | Heavy-pattern nuts used with high-strength bolts and studs |
| ASTM A194 Grade 2HM Hex Nuts | Standard hex-pattern nuts for compatible bolting assemblies |
| 2HM Jam Nuts | Reduced-height nuts used where installation space is limited, subject to specification requirements |
| 2HM Locking Nut Assemblies | Used where additional resistance to loosening is required |
| ASME SA194 Grade 2HM Nuts | ASME-designated equivalent for pressure equipment applications |
| Custom 2HM Nuts | Manufactured to specified dimensions, threads, coatings, and inspection requirements |
Heavy hex nuts are especially common in industrial flange and pressure-equipment applications because their larger bearing surface and wrenching dimensions support demanding bolted connections.
ASTM A194 Gr 2HM Fasteners Specifications
| Property | ASTM A194 Grade 2HM |
|---|---|
| Standard | ASTM A194/A194M |
| ASME Designation | ASME SA194 |
| Grade | 2HM |
| Material | Carbon Steel |
| Condition | Quenched & Tempered |
| Minimum Tempering Temperature | 1150°F (620°C) |
| Common Product | Heavy Hex Nuts |
| Hardness | 159–235 HB |
| Rockwell Hardness | 84–99 HRB |
| Application | High-pressure, high-temperature and sour-service bolting |
| Dimensional Standard | ASME B18.2.2 / applicable purchase specification |
| Size Range | Commonly 1/4 in to 4 in; metric sizes available according to requirements |
Mechanical Properties of ASTM A194 Grade 2HM Nuts
The most important mechanical characteristic of ASTM A194 2HM Sour Service Fasteners is controlled hardness. Available specification data identifies Grade 2HM with a completed-nut hardness range of approximately 159–235 HB and 84–99 HRB.
ASTM A194 Grade 2HM Mechanical Properties Chart
| Mechanical Property | ASTM A194 Grade 2HM |
|---|---|
| Brinell Hardness | 159–235 HB |
| Rockwell Hardness | 84–99 HRB |
| Proof Load Stress – Heavy Hex | 150 ksi |
| Proof Load Stress – Hex | 135 ksi |
| Minimum Tempering Temperature | 1150°F (620°C) |
| Heat Treatment | Quenched & Tempered |
| Post-Machining Stress Relief | Required |
ASTM A194 Grade 2HM Weight Chart
The following chart provides approximate theoretical weights for commonly supplied Grade 2HM heavy hex nuts. Actual weight can vary with thread pitch, tolerances, dimensional standard, chamfer, and manufacturing configuration. Final weights should therefore be confirmed against the approved dimensional drawing or purchase specification.
A194 Gr 2HM Heavy Hex Nuts Weight Chart
| Nominal Size | Approx. Weight per 100 Nuts (kg) |
|---|---|
| 1/4" | 0.9 |
| 5/16" | 1.5 |
| 3/8" | 2.3 |
| 7/16" | 3.1 |
| 1/2" | 4.2 |
| 9/16" | 5.5 |
| 5/8" | 7.0 |
| 3/4" | 11.5 |
| 7/8" | 17.0 |
| 1" | 24.0 |
| 1-1/8" | 32.0 |
| 1-1/4" | 42.0 |
| 1-3/8" | 53.0 |
| 1-1/2" | 65.0 |
| 1-5/8" | 79.0 |
| 1-3/4" | 94.0 |
| 2" | 125.0 |
ASTM A194 Grade 2HM Equivalent Grades Chart
| Standard / Designation | Equivalent / Reference |
|---|---|
| ASTM | A194 Grade 2HM |
| ASME | SA194 Grade 2HM |
| UNS | K04100* |
| Material Type | Medium Carbon Steel |
| Heat Treatment | Quenched & Tempered |
| DIN / EN | No exact direct equivalent |
| JIS | No exact direct equivalent |
| ISO | No exact direct equivalent |
NACE MR0175 ASTM A194 Grade 2HM Nuts
NACE MR0175 ASTM A194 Grade 2HM Nuts are used in applications where material selection for sour-service environments is important. Hydrogen sulfide-containing environments can create specific risks such as sulfide stress cracking, making hardness control and compliance with the applicable sour-service requirements particularly important.
Grade 2HM is associated with controlled hardness requirements, which is one reason this grade is selected for certain sour-service bolting applications. However, compliance with NACE MR0175 / ISO 15156 should never be assumed solely from the ASTM grade. The complete material condition, hardness, environment, temperature, and project requirements must be reviewed before specifying the nuts.
For sour-service orders, we can provide the applicable inspection and documentation requirements when they are stated in the purchase specification.
Manufacturing Process of ASTM A194 Gr 2HM Fasteners
Applications of ASTM A194 Grade 2HM Fasteners
The controlled mechanical properties of ASTM A194 Grade 2HM Fasteners make them suitable for critical industrial bolting applications, including:
- Oil and gas pipelines
- Refineries
- Petrochemical plants
- Chemical processing plants
- Pressure vessels
- Heat exchangers
- Power generation equipment
- Process piping
- Valves and pumps
- Flanges and pipe connections
- Offshore and onshore equipment
- Sour-service installations
These fasteners are generally selected where the bolting system must satisfy specific pressure, temperature, hardness, and material compatibility requirements.
Why Choose Us for ASTM A194 Gr 2HM Fasteners?
We supply ASTM A194 Gr 2HM Fasteners with attention to material traceability, dimensional accuracy, heat-treatment requirements, and customer-specific inspection needs. Our range can be supplied for standard industrial requirements as well as engineered projects requiring specific sizes, threads, coatings, documentation, and testing.
As an ASTM A194 Gr 2HM Fasteners Manufacturer, we support customers with:
- ASTM A194/A194M Grade 2HM compliant products
- Heavy hex and hex nut configurations
- Standard and customized dimensions
- Controlled heat-treatment processes
- Hardness and proof-load testing
- Material traceability
- Inspection documentation
- Export-quality packaging
- Bulk and project-based orders
We also serve customers looking for an ASME SA194 Grade 2HM Nuts Stockist and an ASTM A194 Grade 2HM Fasteners Supplier in India, with supply options tailored to project specifications.
Order ASTM A194 Gr 2HM Fasteners With Confidence
From standard heavy hex nuts to project-specific sour-service requirements, we help customers source ASTM A194 Gr 2HM Fasteners with appropriate technical documentation and quality controls.
Contact us with your drawings, specifications, quantity, and application requirements to discuss the right ASTM A194 Grade 2HM Fasteners for your project.
ASTM A194 Gr 2HM Fasteners – FAQs
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