Standards
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175 / ISO 15156-2
- NORSOK M-650 Qualified
- API 6A Certified
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Incoloy 925 Bolts (UNS N09925) — Bolting Hub
Hex bolts, heavy hex bolts, stud bolts, cap screws, anchor bolts, eye bolts in nickel-iron-chromium alloy
Incoloy 925 bolts (UNS N09925) is the broad bolting hub on this site, covering every head-style fastener in the alloy. The choice of bolt type depends on the joint configuration: head form (hex / heavy hex / square / socket / countersunk), thread reach (full or partial), end form (chamfered / cup / oval), and whether the bolt is used with a nut, threaded into a tapped hole, embedded in concrete, or anchored in another fastening medium. All Incoloy 925 bolts share the same metallurgy, aged condition delivering 110 ksi yield, 165 ksi tensile, with hardness controlled within the NACE MR0175 35 HRC sour-service cap, what differs is the geometry. This page is the navigation hub for the specific bolt-type pages; for the API 6A wellhead-spec stud-and-nut bolting that drives most volume, see stud bolts.
Need Incoloy 925 bolts? Email info@torqbolt.com with bolt type, diameter × length, thread series, quantity, applicable standards. WhatsApp +91-22-66157017.
Bolt Types, Pick the Right Page
| Bolt Type | Standard | Use | Page |
|---|---|---|---|
| Stud bolts (full-thread, 2 nuts) | ASTM B805 / ASTM A193 / API 6A | API 6A wellhead, Christmas tree, BOP, flange bolting | stud bolts |
| Hex bolts (integral hex head) | ASME B18.2.1 / ISO 4014 | General structural + machinery bolting | hex bolts |
| Heavy hex bolts (larger AF, structural) | ASME B18.2.6 / EN 14399 | High-load structural-steel + pressure-vessel | heavy hex bolts |
| Hex cap screws (precision) | ASME B18.2.1 Grade A / ISO 4014 Grade A | Rotating machinery, valve internals, precision joints | hex cap screws |
| Socket head cap screws (internal hex) | ASME B18.3 / DIN 912 | Tight-clearance + counterbored applications | socket head cap screws |
| 12-point screws (external 12-point drive) | ASME B18.2.7M / NAS 1351 | Aerospace + high-torque tight-access bolting | 12-point screws |
| Countersunk screws (flush head) | ASME B18.6.3 / DIN 7991 | Flush-surface fastening; aerodynamic / aesthetic joints | countersunk screws |
| Set screws (grub / headless) | ASME B18.3 / DIN 913–916 | Shaft-collar + hub-locking applications | set screws |
| Push bolts (for body removal / extraction) | Customer drawing | Push-out service for hub / bushing extraction | push bolts |
| U-bolts (curved-form rod) | ASME / customer drawing | Pipe / cable / shaft clamping | u-bolts |
| Threaded rods (continuous-thread, cut to length) | ASTM F1554 / DIN 976 | Cut-to-length stud + anchor-rod service | threaded rods |
| Studs (broad category, includes welding studs) | ASME B18.31.2 / DIN 938–940 / AWS D1.6 | Tap-end / welding / continuous variants | studs |
Common Mechanical Properties (All Bolt Types, Aged)
| Property | Aged Condition (ASTM B805 min) |
|---|---|
| Tensile Strength | 165 ksi (1140 MPa) min |
| 0.2% Yield Strength | 110 ksi (760 MPa) min |
| Elongation in 4D | 18% min |
| Hardness | 32–35 HRC (NACE sour-service cap) |
| Charpy V-notch at -46°C | 40 J min (NACE) |
Selecting the Right Bolt Type
- API 6A wellhead / Christmas tree bolting: Use stud bolts with heavy hex nuts per API 6A spec.
- Pressure vessel bonnet bolting (one-sided access): Use hex bolts or heavy hex bolts + nut on accessible side.
- Rotating machinery (precision joints): Use hex cap screws with washer face.
- Tight-clearance / counterbored joints: Use socket head cap screws.
- High-torque aerospace / tight-access: Use 12-point external-drive screws.
- Flush-surface joints: Use countersunk flat-head screws.
- Shaft / collar locking: Use set screws (cup point / cone point / dog point per application).
- Pipe / cable / shaft clamping: Use u-bolts.
- Hub / bushing extraction: Use push bolts.
- Concrete-embedded foundation: Use threaded rods per ASTM F1554 anchor-rod variant.
- Welded attachment to substrate: Use welding studs per studs page.
Common Standards
- ASTM B805, UNS N09925 forgings & forging stock (input bar for all bolt types)
- ASTM A193 Grade B8N / ASTM F2281, bolting materials specifications
- ASTM A320 Grade L7, cryogenic bolting (when -101°C Charpy required)
- ASME B18 series, dimensional standards per bolt type (B18.2.1 / B18.2.6 / B18.3 / B18.6.3 / B18.2.7M / B18.31.2)
- ISO 4014 / 4017 / DIN 933 / 931, metric hex bolts
- API 6A, Wellhead and Tree Equipment (PSL-1 to PSL-4)
- API 20E, Alloy and Carbon Steel Bolting (BSL-1 / 2 / 3 quality levels)
- NACE MR0175 / ISO 15156-3, Table A.10 sour service
- NORSOK M-630 MDS A30, Norwegian Continental Shelf bolting
- EN 10204 3.1 / 3.2, certification
Frequently Asked Questions
Which Incoloy 925 bolt type is most common in oilfield service? The stud bolt + 2× heavy hex nuts + washers assembly per API 6A is by far the most common, it is the bolting on every wellhead, Christmas tree, BOP and major production-flange joint in sour H₂S service worldwide. Hex bolts and cap screws are more common in machinery, valve internals and structural service.
What's the difference between Incoloy 925 bolts and Incoloy 825 bolts? See Incoloy 925 vs 825: 925 is age-hardenable to 110 ksi YS; 825 is solid-solution at ~45 ksi YS. For high-strength bolting, 925 is the only practical choice; 825 is reserved for low-load piping and vessel internals.
What's the typical lead time? Standard sizes / standard bolt types: 4–6 weeks. Larger sizes / specialty bolt types (12-point / countersunk / welding stud / push bolt): 6–10 weeks. Custom drawings: quote-by-quote.
Documentation Package
- EN 10204 3.1 manufacturer's MTC (3.2 with TPI on request)
- Heat-lot chemistry vs UNS N09925 limits
- Tensile + RA + elongation per heat / per heat-treatment lot
- 100% hardness inspection (32–35 HRC NACE band)
- Charpy at -46°C / -101°C as applicable
- Heat-treatment chart-recorder traces
- Dimensional inspection ASME B18 series + thread Go / No-Go ASME B1.3
- NACE MR0175 Table A.10 reference
- API 6A PSL level reference (TPI for PSL-4)
- Bolt marking: heat number + UNS N09925 + standard ref + NACE stamp
Request a Quote
For Incoloy 925 bolts of any type with full MTC documentation:
- Email: info@torqbolt.com
- Phone: +91-22-66157017
- WhatsApp: +91-22-66157017
Specify bolt type (or describe the application and we'll recommend), diameter × length, thread series, quantity, applicable standards, required MTC level (3.1 / 3.2 with TPI witness) and any coating / finish requirement.
References: ASTM B805; ASTM A193 / A320 / F2281; ASME B18 series (B18.2.1 / B18.2.6 / B18.3 / B18.6.3 / B18.2.7M / B18.31.2); ISO 4014 / 4017 / DIN 933 / 931 / 912 / 7991 / 913–916; API Specification 6A; API 20E; NACE MR0175 / ISO 15156-3 Table A.10; NORSOK M-630 / M-650; EN 10204. Special Metals Corporation INCOLOY® alloy 925 Technical Bulletin. INCOLOY® is a registered trademark of Special Metals Corporation.
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