ASME B18.31.2 Fully Threaded Stud Bolts for Industrial Flange Connections
We specialize in manufacturing and supplying ASME B18.31.2 threaded studs — delivering exceptional performance, strength, and resistance for your most-demanding applications.
ASME B18.31.2 continuous thread stud bolts are fully threaded fasteners designed for use in flanged joints, pressure vessels, and high-strength bolting applications. Manufactured in accordance with ASME B18.31.2, these stud bolts provide uniform load distribution, reliable clamping force, and compatibility with a wide range of nuts and flange standards.
Continuous thread stud bolts are widely used in oil & gas, petrochemical, power generation, offshore, and heavy industrial piping systems.
What Are ASME B18.31.2 Continuous Thread Stud Bolts？
ASME B18.31.2 specifies the dimensions, materials, and technical requirements for continuous thread studs (also known as threaded rod) used in pressure vessels, flanges, and industrial machinery.
Continuous thread studs enable ease of installation, strong clamping, and flexible length adjustment — making them a preferred choice for many heavy-duty applications.
ASME B18.31.2 – Continuous Thread Stud, Double-End Stud, and Flange Bolting Stud (Stud Bolt) (Inch Series)
This standard covers the dimensional and material requirements for continuous-thread and double-end threaded studs, used primarily for bolting flanged connections, valves, pressure vessels, and other industrial applications
ASME B18.31.2 Scope
ASME B18.31.2 provides specifications for:
- Continuous Thread Studs (Fully Threaded Rods):
Threads run the full length of the stud. - Double-End Studs:
Threads on both ends, with a plain (unthreaded) center portion. Used when bolted parts are removed frequently.
Dimensions and specification
| Feature | Details |
|---|---|
| Thread Series | UNC (Coarse) and UNF (Fine) as per ASME B1.1 |
| Nominal Diameters | 1/4 inch through 4 inches |
| Stud Lengths | Specified in inches, typically from 1″ up to 48″ |
| End Configuration | Chamfered ends, optional radius or 45° bevel |
| Unthreaded Center (Double-End) | Minimum 1.5 × diameter between threaded portions |
Dimensions for Continuous thread studs
Stud bolt Materials made according to ASME B18.31.2
| ASTM A307 | Grade A & B |
| ASTM A320, A320M | Grade L7, L7M, B8, B8M |
| ASTM A325, A325M | Grade 8.8 |
| ASTM A490, A490M | Grade 10.9 |
| ASTM A193/A193M | Grade B7, B7M, B8, B8M, B16 |
Testing & Quality Requirements
Stud bolts manufactured to ASME B18.31.2 are typically supplied with:
- Dimensional inspection
- Thread gauge inspection
- Chemical analysis (per ASTM material standard)
- Mechanical testing (tensile, hardness)
- Certification: EN 10204 3.1 / 3.2 (upon request)
Customised Coating Systems on stud bolt
Zinc + Fluorocarbon / PTFE
Cadmium + Fluorocarbon /PTFE
Zinc Nickel + Fluorocarbon /PTFE
Zinc Plating + Xylan 1424 Blue coated stud bolt
Xylar 2 + Xylan 1070 Blue coated stud bolt
Standard reference
| Standard | Description |
|---|---|
| ASME B1.1 | Unified Inch Screw Threads (UNC/UNF) |
| ASME B18.2.1 | Hex Bolts and Screws |
| ASME B18.2.2 | Hex Nuts |
ASME B18.31.2 continuous thread stud bolts provide reliable fastening solutions for high-pressure and critical bolted joints. With precise dimensional control, full-thread engagement, and compatibility with ASTM bolting materials, these stud bolts are widely specified for industrial and energy applications.
