What is ASME?
The American Society of Mechanical Engineers (ASME) is a globally recognized standards-developing organization that publishes engineering codes governing the design, dimensions, and performance of mechanical components used in pressure systems, piping, and industrial equipment.
ASME fasteners are manufactured and dimensioned in accordance with ASME standards and ASME specifications, which define critical parameters such as thread forms, dimensional tolerances, geometry, and load performance. These standards ensure consistent fitment, interchangeability, and safety in pressure-containing and load-bearing assemblies.
Unlike material-focused specifications, ASME standards concentrate on how a fastener is shaped, sized, and assembled, while material strength and chemical composition are typically governed by ASTM grades. As a result, ASME specifications are commonly applied alongside ASTM material standards within the broader fastener standards framework to achieve full compliance in piping, petrochemical, power generation, and pressure vessel applications.
ASME Fastener Standards
The following table outlines the most commonly referenced ASME standards for fasteners, covering bolts, nuts, studs, threads, and dimensional requirements.
| ASME Standard | Description / Scope |
|---|---|
| ASME B16.5 | Dimensions and tolerances for studs and hex bolts used with Class 150 / 300 / 400 / 600 / 900 / 1500 / 2500 flanges, covering sizes from 1/2” to 24”. |
| ASME B16.47 | Dimensions and tolerances for studs and hex bolts for large diameter flanges (Class 150 / 300 / 400 / 600 / 900) ranging from 26” to 60”. |
| ASME B18.10 | Standard dimensions for oval neck track bolts and matching nuts used in rail and industrial applications. |
| ASME B18.15 | Standard dimensions for carbon steel and stainless steel forged eye bolts, including shoulder pattern and plain eye bolts. |
| ASME B18.16.3M | Standard dimensions for prevailing-torque type steel metric hex nuts and metric hex flange nuts. |
| ASME B18.16.4 | Dimensional standard for serrated hex flange nuts used for vibration resistance. |
| ASME B18.16.6 | Dimensional standard for nylon insert hex lock nuts (nylock nuts). |
| ASME B18.2.1 | Dimensional standard covering square bolts, hex bolts, heavy hex bolts, askew head bolts, hex flange bolts, lobed head bolts, and lag screws. |
| ASME B18.2.2 | Dimensional standard for machine screw nuts including hex nuts, square nuts, hex flange nuts, and coupling nuts. |
| ASME B18.2.3.1M | Dimensional standard for metric hex cap screws covering sizes from M5 to M100. |
| ASME B18.2.3.2M | Dimensional standard for metric hex cap screws covering sizes from M5 to M24. |
| ASME B18.2.3.3M | Dimensional standard for metric heavy hex cap screws covering sizes from M12 to M36. |
| ASME B18.2.3.4M | Dimensional standard for metric hex flange screws covering sizes from M5 to M16. |
| ASME B18.2.3.5M | Dimensional standard for metric hex bolts covering sizes from M5 to M100. |
| ASME B18.3 | Dimensional and performance requirements for socket head cap screws, shoulder screws, and set screws. |
| ASME B18.31.1 | Standard for continuous thread studs used with nuts in bolted assemblies. |
| ASME B18.31.2 | Standard for full-length threaded studs commonly used in pressure vessels and flanged joints. |
| ASME B1.1 | Unified Inch Screw Thread standard defining thread form, tolerances, and classes of fit (UNC, UNF, UNEF). |
| ASME B1.13M | Metric screw thread standard defining ISO metric thread dimensions and tolerances. |
ASME Specifications vs ASTM Specifications
A common misconception is that ASME and ASTM standards are interchangeable. In reality, they serve distinct but complementary roles in fastener engineering.
| Aspect | ASME | ASTM |
|---|---|---|
| Primary Focus | Design & dimensions | Material & mechanical properties |
| Governs | Threads, tolerances, geometry | Chemical composition, strength |
| Typical Example | ASME B18.2.1 | ASTM A193 B7 |
| Used Together | Yes | Yes |
Where ASME Fasteners Are Used?
ASME-compliant fasteners are mandatory or preferred in industries where pressure, safety, and code compliance are critical:
- Pressure vessels
- Oil & gas pipelines
- Power plants
- Heat exchangers
- Valves and flanged joints
- Petrochemical and refinery units
ASME fasteners are commonly referenced in ASME Boiler and Pressure Vessel Code (BPVC) and piping codes such as ASME B31.
ASME Fasteners Supplied by Jade Alloys
At Jade Alloys, we manufacture and supply fasteners that conform to applicable ASME dimensional standards, combined with certified ASTM material grades.
Our Capabilities Include:
- ASME-compliant hex bolts and stud bolts
- Heavy hex nuts as per ASME B18.2.2
- Unified thread forms (UNC / UNF)
- Full traceability with Material Test Certificates (MTC)
- Third-party inspection on request
We support both standard and custom ASME fasteners for domestic and export projects.
