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Flange stud bolts are precision-engineered threaded fasteners designed to secure pipe flanges in high-pressure, high-temperature, and vibration-prone systems. They are widely used in oil & gas pipelines, petrochemical refineries, power generation units, and offshore platforms where joint integrity is critical. These bolts provide uniform clamping force across flange faces, ensuring leak-proof sealing when paired with appropriate nuts and gaskets.
Manufactured in compliance with international standards such as ASTM A193, DIN 976, and ISO 898, flange stud bolts are available in multiple grades including stainless steel, carbon steel, and alloy steel variants. Their full-threaded design allows controlled torque distribution, making them ideal for flange bolting systems requiring precise preload tensioning.
KK Fasteners supplies engineered flange stud bolts to industrial clients across global infrastructure sectors, ensuring consistent dimensional accuracy, material traceability, and performance reliability for mission-critical assemblies.
| Parameter | Details |
|---|---|
| Material Grades | SS 304, SS 316, SS 316L, ASTM A193 B7, B7M, Alloy Steel, Carbon Steel |
| Size Range | M6 to M100 / 1/4" to 4" (custom sizes available) |
| Thread Type | Metric (ISO), UNC, UNF, BSW |
| Standards | DIN 976, ASTM A193, ASTM A320, ISO 898, BS 3692 |
| Surface Finish | Black Oxide, Zinc Plated, Hot Dip Galvanized, PTFE Coated |
| Type | Full Threaded Stud Bolts / Double-End Studs |
| Tensile Strength | Up to 1200 MPa (depending on grade) |
| Forming | Hot & Cold Forged |
|---|---|
| Metric Size | M10 to M100 |
| Imperial Size | 3/8" to 4" |
| Threads | UNC, UNF, ISO, BSW & ACME. |
| Standards | DIN, ASME, ISO & IS |
| Variants |
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| Dimension Standards |
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| Alloy Categories |
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| ASTM Specifications |
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| Coatings |
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| Class 150 Flanges ASME B16.5 (Stud bolt sizes) | Length of Stud Bolts | |||||||
| NPS | Outside Diameter of Flange | The diameter of Bolt Circle | The diameter of Bolt Holes | Number of Bolts | Diameter of Bolts | Raised Face 0.06 in |
Ring Joint | |
| 1/2 | 3 1/2 | 2 3/8 | 5/8 | 4 | 1/2 | 2 1/4 | – | |
| 3/4 | 3 7/8 | 2 3/4 | 5/8 | 4 | 1/2 | 2 1/2 | – | |
| 1 | 4 1/4 | 3 1/8 | 5/8 | 4 | 1/2 | 2 1/2 | 3 | |
| 1 1/4 | 4 5/8 | 3 1/2 | 5/8 | 4 | 1/2 | 2 3/4 | 3 1/4 | |
| 1 1/2 | 5 | 3 7/8 | 5/8 | 4 | 1/2 | 2 3/4 | 3 1/4 | |
| 2 | 6 | 4 3/4 | 3/4 | 4 | 5/8 | 3 1/4 | 3 3/4 | |
| 2 1/2 | 7 | 5 1/2 | 3/4 | 4 | 5/8 | 3 1/2 | 4 | |
| 3 | 7 1/2 | 6 | 3/4 | 4 | 5/8 | 3 1/2 | 4 | |
| 3 1/2 | 8 1/2 | 7 | 3/4 | 8 | 5/8 | 3 1/2 | 4 | |
| 4 | 9 | 7 1/2 | 3/4 | 8 | 5/8 | 3 1/2 | 4 | |
| 5 | 10 | 8 1/2 | 7/8 | 8 | 3/4 | 3 3/4 | 4 1/4 | |
| 6 | 11 | 9 1/2 | 7/8 | 8 | 3/4 | 4 | 4 1/2 | |
| 8 | 13 1/2 | 11 3/4 | 7/8 | 8 | 3/4 | 4 1/4 | 4 3/4 | |
| 10 | 16 | 14 3/4 | 1 | 12 | 7/8 | 4 1/2 | 5 | |
| 12 | 19 | 17 | 1 | 12 | 7/8 | 4 3/4 | 5 1/4 | |
| 14 | 21 | 18 3/4 | 1 1/8 | 12 | 1 | 5 1/4 | 5 3/4 | |
| 16 | 23 1/2 | 21 1/4 | 1 1/8 | 16 | 1 | 5 1/4 | 5 3/4 | |
| 18 | 25 | 22 3/4 | 1 1/4 | 16 | 1 1/8 | 5 3/4 | 6 1/4 | |
| 20 | 27 1/2 | 25 | 1 1/4 | 20 | 1 1/8 | 6 1/4 | 6 3/4 | |
| 24 | 32 | 29 1/2 | 1 1/4 | 20 | 1 1/4 | 6 3/4 | 7 1/4 | |
| Class 300 Flanges ASME B16.5 | Length of Stud Bolts | |||||||
| NPS | Outside Diameter of Flange | The diameter of Bolt Circle | The diameter of Bolt Holes | Number of Bolts | Diameter of Bolts | Raised Face 0.06 in |
Ring Joint | |
| 1/2 | 3 3/4 | 2 5/8 | 5/8 | 4 | 1/2 | 2 1/2 | 3 | |
| 3/4 | 4 5/8 | 3 1/4 | 3/4 | 4 | 5/8 | 3 | 3 1/2 | |
| 1 | 4 7/8 | 3 1/2 | 3/4 | 4 | 5/8 | 3 | 3 1/2 | |
| 1 1/4 | 5 1/4 | 3 7/8 | 3/4 | 4 | 5/8 | 3 1/4 | 3 3/4 | |
| 1 1/2 | 6 1/8 | 4 1/2 | 7/8 | 4 | 3/4 | 3 1/2 | 4 | |
| 2 | 6 1/2 | 5 | 3/4 | 8 | 5/8 | 3 1/2 | 4 | |
| 2 1/2 | 7 1/2 | 5 7/8 | 7/8 | 8 | 3/4 | 4 | 4 1/2 | |
| 3 | 8 1/4 | 6 5/8 | 7/8 | 8 | 3/4 | 4 1/4 | 4 3/4 | |
| 3 1/2 | 9 | 7 1/4 | 7/8 | 8 | 3/4 | 4 1/4 | 5 | |
| 4 | 10 | 7 7/8 | 7/8 | 8 | 3/4 | 4 1/2 | 5 | |
| 5 | 11 | 9 1/4 | 7/8 | 8 | 3/4 | 4 3/4 | 5 1/4 | |
| 6 | 12 1/2 | 10 5/8 | 7/8 | 12 | 3/4 | 4 3/4 | 5 1/2 | |
| 8 | 15 | 13 | 1 | 12 | 7/8 | 5 1/2 | 6 | |
| 10 | 17 1/2 | 15 1/4 | 1 1/8 | 16 | 1 | 6 1/4 | 6 3/4 | |
| 12 | 20 1/2 | 17 3/4 | 1 1/4 | 16 | 1 1/8 | 6 3/4 | 7 1/4 | |
| 14 | 23 | 20 1/4 | 1 1/4 | 20 | 1 1/8 | 7 | 7 1/2 | |
| 16 | 25 1/2 | 22 1/2 | 1 3/8 | 20 | 1 1/4 | 7 1/2 | 8 | |
| 18 | 28 | 24 3/4 | 1 3/8 | 24 | 1 1/4 | 7 3/4 | 8 1/4 | |
| 20 | 30 1/2 | 27 | 1 3/8 | 24 | 1 1/4 | 8 | 8 3/4 | |
| 24 | 36 | 32 | 1 5/8 | 24 | 1 1/2 | 9 | 10 | |
| Class 900 Flanges ASME B16.5 | Length of Stud Bolts | |||||||
| NPS | Outside Diameter of Flange | The diameter of Bolt Circle | The diameter of Bolt Holes | Number of Bolts | Diameter of Bolts | Raised Face 0.06 in |
Ring Joint | |
| 1/2 | 4 3/4 | 3 1/4 | 7/8 | 4 | 3/4 | 4 1/4 | 4 1/4 | |
| 3/4 | 5 1/8 | 3 1/2 | 7/8 | 4 | 3/4 | 4 1/2 | 4 1/2 | |
| 1 | 5 7/8 | 4 | 1 | 4 | 7/8 | 5 | 5 | |
| 1 1/4 | 6 1/4 | 4 3/8 | 1 | 4 | 7/8 | 5 | 5 | |
| 1 1/2 | 7 | 4 7/8 | 1 1/8 | 4 | 1 | 5 1/2 | 5 1/2 | |
| 2 | 8 1/2 | 6 1/2 | 1 | 8 | 7/8 | 5 3/4 | 5 3/4 | |
| 2 1/2 | 9 5/8 | 7 1/2 | 1 1/8 | 8 | 1 | 6 1/4 | 6 1/4 | |
| 3 | 9 1/2 | 7 1/2 | 1 | 8 | 7/8 | 5 3/4 | 5 3/4 | |
| 4 | 11 1/2 | 9 1/4 | 1 1/4 | 8 | 1 1/8 | 6 3/4 | 6 3/4 | |
| 5 | 13 3/4 | 11 | 1 3/8 | 8 | 1 1/4 | 7 1/2 | 7 1/2 | |
| 6 | 15 | 12 1/2 | 1 1/4 | 12 | 1 1/8 | 7 1/2 | 7 3/4 | |
| 8 | 18 1/2 | 15 1/2 | 1 1/2 | 12 | 1 3/8 | 8 3/8 | 8 3/4 | |
| 10 | 21 1/2 | 18 1/2 | 1 1/2 | 16 | 1 3/8 | 9 1/4 | 9 1/4 | |
| 12 | 24 | 21 | 1 1/2 | 20 | 1 3/8 | 10 | 10 | |
| 14 | 25 1/4 | 22 | 1 5/8 | 20 | 1 1/2 | 10 3/4 | 11 | |
| 16 | 27 3/4 | 24 1/4 | 1 3/4 | 20 | 1 5/8 | 11 1/4 | 11 1/2 | |
| 18 | 31 | 27 | 2 | 20 | 1 7/8 | 12 3/4 | 13 1/4 | |
| 20 | 33 3/4 | 29 1/2 | 2 1/8 | 20 | 2 | 13 3/4 | 14 1/4 | |
| 24 | 41 | 35 1/2 | 2 5/8 | 20 | 2 1/2 | 17 1/4 | 18 | |
| Class 1500 Flanges ASME B16.5 | Length of Stud Bolts | |||||||
| NPS | Outside Diameter of Flange | The diameter of Bolt Circle | The diameter of Bolt Holes | Number of Bolts | Diameter of Bolts | Raised Face 0.06 in |
Ring Joint | |
| 1/2 | 4 3/4 | 3 1/4 | 7/8 | 4 | 3/4 | 4 1/4 | 4 1/4 | |
| 3/4 | 5 1/8 | 3 1/2 | 7/8 | 4 | 3/4 | 4 1/2 | 4 1/2 | |
| 1 | 5 7/8 | 4 | 1 | 4 | 7/8 | 5 | 5 | |
| 1 1/4 | 6 1/4 | 4 3/8 | 1 | 4 | 7/8 | 5 | 5 | |
| 1 1/2 | 7 | 4 7/8 | 1 1/8 | 4 | 1 | 5 1/2 | 5 1/2 | |
| 2 | 8 1/2 | 6 1/2 | 1 | 8 | 7/8 | 5 3/4 | 5 3/4 | |
| 2 1/2 | 9 5/8 | 7 1/2 | 1 1/8 | 8 | 1 | 6 1/4 | 6 1/4 | |
| 3 | 10 1/2 | 8 | 1 1/4 | 8 | 1 1/8 | 7 | 7 | |
| 4 | 12 1/4 | 9 1/2 | 1 3/8 | 8 | 1 1/4 | 7 3/4 | 7 3/4 | |
| 5 | 14 3/4 | 11 1/2 | 1 5/8 | 8 | 1 1/2 | 9 3/4 | 9 3/4 | |
| 6 | 15 1/2 | 12 1/2 | 1 1/2 | 12 | 1 3/8 | 10 1/4 | 10 1/2 | |
| 8 | 19 | 15 1/2 | 1 3/4 | 12 | 1 5/8 | 11 1/2 | 12 3/4 | |
| 10 | 23 | 19 | 2 | 12 | 1 7/8 | 13 1/4 | 13 1/2 | |
| 12 | 26 1/2 | 22 1/2 | 2 1/8 | 16 | 2 | 14 3/4 | 15 1/4 | |
| 14 | 29 1/2 | 25 | 2 3/8 | 16 | 2 1/4 | 16 | 16 3/4 | |
| 16 | 32 1/2 | 27 3/4 | 2 5/8 | 16 | 2 1/2 | 17 1/2 | 18 1/2 | |
| 18 | 36 | 30 1/2 | 2 7/8 | 16 | 2 3/4 | 19 1/2 | 20 3/4 | |
| 20 | 38 3/4 | 32 3/4 | 3 1/8 | 16 | 3 | 21 1/4 | 22 1/4 | |
| 24 | 46 | 39 | 3 5/8 | 16 | 3 1/2 | 24 1/4 | 25 1/2 | |
Flange stud bolts are used wherever flanged joints must withstand pressure, temperature fluctuations, and vibration while maintaining leak-proof integrity.
Flange stud bolts are manufactured using precision cold forging and CNC threading processes to ensure uniform grain flow and dimensional accuracy. Heat treatment cycles are applied to achieve required mechanical properties such as tensile strength and hardness stability. Each batch undergoes rigorous inspection including dimensional verification, thread gauging, hardness testing, and surface finish analysis.
KK Fasteners implements full lot traceability with material test certificates (MTC) aligned to EN 10204 3.1 standards. Compliance with ISO 9001:2015, RoHS, and REACH ensures global industrial acceptance. Every flange stud bolt is validated for torque performance consistency before dispatch, ensuring reliability in critical bolting applications.
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Flange stud bolts are fully threaded fasteners used to join pipe flanges in pressure systems. They work with nuts on both ends to create uniform clamping force, ensuring leak-proof and vibration-resistant joints in pipelines, pressure vessels, and industrial equipment.
The choice depends on application conditions. ASTM A193 B7 carbon steel is widely used for high-strength requirements in oil & gas systems, while stainless steel grades like SS 316 are preferred for corrosive environments such as marine, chemical, and offshore installations.
Flange stud bolts are commonly manufactured according to ASTM A193, ASTM A320, DIN 976, ISO 898, and BS 3692 standards. These define mechanical strength, dimensional accuracy, and material performance for safe industrial flange connections.
Selection depends on flange rating, operating pressure, temperature, and environmental exposure. Engineers typically match bolt grade and size with ASME flange specifications to ensure proper torque, sealing performance, and long-term joint reliability.
Look for manufacturers with ISO certification, material traceability, and compliance with international standards like ASTM and DIN. Reliable suppliers also provide test certificates, inspection reports, and proven export experience. KK Fasteners supports global industries with certified production and documented quality assurance.
Flange stud bolts play a critical role in ensuring structural integrity across high-pressure industrial systems where failure is not an option. With precision engineering, certified materials, and strict quality control, KK Fasteners delivers reliable fastening solutions tailored for global infrastructure and industrial demands.
For technical specifications, custom requirements, or bulk supply inquiries, connect with KK Fasteners to receive engineered support and project-specific quotations designed for your application needs.
