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 Mechanical Properties (UNS N09925)
Per ASTM B805 + Special Metals Technical Bulletin — annealed, age-hardened, elevated-temperature, and Charpy impact data
Incoloy 925 (UNS N09925) is an age-hardenable nickel-iron-chromium alloy whose mechanical properties depend critically on heat treatment condition. In the solution-annealed condition (1900°F / 1040°C, water quenched), the alloy delivers 110 ksi minimum tensile strength with high ductility for forming. After the precipitation-hardening age cycle (1365°F / 740°C × 8 hr, air cooled), Ni₃(Al, Ti) gamma-prime nano-precipitates lift yield strength from ~50 ksi to a guaranteed 110 ksi minimum and tensile strength to 165 ksi minimum, the values codified in ASTM B805 and used in API 6A wellhead bolting specifications. TorqBolt manufactures Incoloy 925 in both conditions with EN 10204 3.1 manufacturer's MTC documenting actual heat-lot tensile, yield, elongation, RA, hardness and Charpy values vs the specified minimums.
Need certified mechanical test data? Email info@torqbolt.com with product type, size and quantity. Sample MTC + full datasheet available on request. Charpy at -46°C (NACE MR0175) and -101°C (cryogenic / API 6A PSL-3G) tested per heat lot.
ASTM B805 Mechanical Property Requirements
| Condition | UTS, ksi (MPa) min | 0.2% YS, ksi (MPa) min | Elong, % min | RA, % min | Hardness, HRC max |
|---|---|---|---|---|---|
| Annealed (1900°F WQ) | 110 (760) | 50 (345) | 30 | 40 | 32 |
| Annealed + Aged (1900°F WQ + 1365°F × 8h AC) | 165 (1140) | 110 (760) | 18 | 25 | 35 |
Source: ASTM B805 Standard Specification for Forgings and Forging Stock for Nuclear and General Use Wrought Precipitation Hardened UNS N09925. Identical envelope appears in ASTM B983 for plate, sheet and strip. The 35 HRC maximum hardness in the aged condition is the cap codified in NACE MR0175 / ISO 15156-3 Table A.10 for sour-service qualification, the single most-watched value on every Incoloy 925 MTC bound for oilfield service.
Room-Temperature Properties, Aged Condition (Typical)
| Property | Bar / Forging (ASTM B805) | Plate / Sheet (ASTM B983) |
|---|---|---|
| Tensile Strength | 165–180 ksi (1140–1240 MPa) | 165–175 ksi (1140–1210 MPa) |
| 0.2% Yield Strength | 110–130 ksi (760–895 MPa) | 110–125 ksi (760–860 MPa) |
| Elongation in 4D | 20–25% | 20–30% |
| Reduction of Area | 30–45% | |
| Hardness | 32–35 HRC | 32–35 HRC |
| Modulus of Elasticity | 27.6 × 10⁶ psi (190 GPa) | 27.6 × 10⁶ psi (190 GPa) |
Elevated-Temperature Tensile Properties (Aged)
Incoloy 925 retains the bulk of its room-temperature strength to ~600°F (315°C), the upper limit of its sour-service envelope. Above this temperature, gamma-prime over-ageing begins to soften the matrix. The data below applies to material in the annealed + aged condition, source: Special Metals Corporation, INCOLOY® alloy 925 Technical Bulletin (Table 7).
| Temperature, °F (°C) | 0.2% Yield Strength, ksi (MPa) | Tensile Strength, ksi (MPa) | Elongation, % |
|---|---|---|---|
| 70 (21) | 110 (760) | 165 (1140) | 22 |
| 200 (93) | 108 (745) | 162 (1117) | 22 |
| 300 (149) | 106 (731) | 160 (1103) | 21 |
| 400 (204) | 104 (717) | 158 (1090) | 20 |
| 500 (260) | 102 (703) | 155 (1069) | 19 |
| 600 (316) | 100 (689) | 153 (1055) | 18 |
| 700 (371) | 97 (669) | 150 (1034) | 17 |
| 800 (427) | 94 (648) | 146 (1007) | 16 |
Charpy V-Notch Impact Toughness — Sour Service Qualification
Incoloy 925 has no true ductile-brittle transition; impact energy decreases gradually with falling temperature. Toughness varies with product form, section size and production route. The values below are typical for material in the aged condition (1900°F WQ + 1365°F × 8h AC) and form the basis for sour-service acceptance per NACE MR0175 / ISO 15156-3 Table A.10 and API 6A PSL-3G material toughness requirements.
| Test Temperature | Bar / Forging (parent) | Welded (HAZ + weld metal) | Standard Acceptance Criterion |
|---|---|---|---|
| +70°F (+21°C) | 120–180 J | 90–140 J | |
| -50°F (-46°C) | 80–120 J | 60–90 J | NACE MR0175 sour: 40 J min (29.5 ft-lb) |
| -150°F (-101°C) | 50–80 J | 35–55 J | API 6A PSL-3G: 27 J min (20 ft-lb) avg, 20 J min single |
A 40 J (30 ft-lb) acceptance threshold at -50°C is the de-facto standard for sour-service nickel-iron-chromium alloys; Incoloy 925 routinely meets this in all product forms. To preserve toughness through welding, parent metal should be specified at >70 J at -58°F (-50°C). TorqBolt's standard MTC includes Charpy at -46°C; -101°C testing is added on request for cryogenic / API 6A PSL-3G applications.
Strength Comparison — Incoloy 925 vs Adjacent Alloys (Aged)
| Alloy | UNS | UTS, ksi (MPa) min | 0.2% YS, ksi (MPa) min | Hardness, HRC max (sour) | NACE MR0175 qualified? |
|---|---|---|---|---|---|
| Incoloy 925 (aged) | N09925 | 165 (1140) | 110 (760) | 35 | Yes (Table A.10) |
| Incoloy 825 | N08825 | 85 (586) | 35 (240) | 30 | Yes (Table A.7) |
| Inconel 718 (aged) | N07718 | 180 (1241) | 150 (1034) | 40 | Yes (Table A.13) |
| Monel K-500 (aged) | N05500 | 130 (896) | 85 (586) | 35 | Yes (Table A.16) |
| Duplex 2205 | S31803 | 90 (621) | 65 (448) | 28 | Yes (super-duplex preferred) |
Incoloy 925 sits in the middle of the sour-service strength ladder, markedly stronger than solid-solution Incoloy 825 (which cannot age-harden), comparable to Monel K-500, and slightly below Inconel 718 (which uses gamma double-prime instead of gamma-prime ageing). The selection trade-off is corrosion envelope vs strength: 925 wins where reducing acids and chlorides are present (Mo + Cu); 718 wins where pure tensile strength rules (gamma double-prime + Nb/Cb).
Common Incoloy 925 Bolting Items & Mechanical Spec Mapping
| Product | Bolting Standard | Required UTS / YS | Hardness Cap (sour) |
|---|---|---|---|
| Stud Bolts | ASTM B805 / API 6A / NACE MR0175 | 165 / 110 ksi | 35 HRC |
| Heavy Hex Nuts | ASTM B805 | matched to bolt grade | 35 HRC |
| Hex Bolts | ASTM B805 / ASME B18.2.1 | 165 / 110 ksi | 35 HRC |
| Washers | ASTM B805 | matched to bolt grade | 35 HRC |
Frequently Asked Questions
Why is the 35 HRC hardness cap so important? Above 35 HRC, Incoloy 925 becomes susceptible to sulfide stress cracking (SSC) in sour environments containing wet H₂S. NACE MR0175 Table A.10 caps qualified hardness at 35 HRC for UNS N09925 in cold-worked + aged condition. Every TorqBolt sour-service order is hardness-tested per heat lot with values reported on the MTC.
Can Incoloy 925 be used in the solution-annealed condition for high-strength applications? No. SA condition delivers only ~50 ksi YS (vs 110 ksi aged minimum), insufficient for API 6A wellhead bolting or any precipitation-hardened spec. SA material is shipped only when the customer plans to do their own heat-treatment cycle, or for applications where formability is more important than strength (cladding, transition pieces).
How does TorqBolt verify mechanical properties? Every heat lot is sample-tested per ASTM E8 (tensile), ASTM E18 (Rockwell hardness), ASTM E92 (Brinell when specified) and ASTM E23 (Charpy V-notch impact). Test results vs the specified minimums are reported on EN 10204 3.1 manufacturer's MTC. EN 10204 3.2 third-party witnessed certification is available on request, specify "3.2 MTC" at RFQ stage.
What is the modulus of elasticity? 27.6 × 10⁶ psi (190 GPa) at room temperature, decreasing to ~24 × 10⁶ psi (165 GPa) at 800°F (427°C). See physical properties page for full elastic modulus and Poisson's ratio data across the temperature range.
Request a Quote
For Incoloy 925 with EN 10204 3.1 MTC documenting actual heat-lot tensile, yield, elongation, RA, hardness and Charpy impact values:
- Email: info@torqbolt.com
- WhatsApp: +91-22-66157017
- Datasheet PDF + sample MTC available on request
Specify product type (stud bolts, nuts, pipe, plate), size range, quantity, condition (aged or annealed), and applicable mechanical-test requirements (Charpy temperature, hardness method, third-party witness).
References: Special Metals Corporation: INCOLOY® alloy 925 Technical Bulletin (Tables 6, 7, 8). ASTM B805 Standard Specification for Forgings and Forging Stock for Nuclear and General Use Wrought Precipitation Hardened UNS N09925. ASTM B983 Standard Specification for Precipitation Hardened UNS N09925 Plate, Sheet, and Strip. NACE MR0175 / ISO 15156-3 Table A.10. INCOLOY® is a registered trademark of Special Metals Corporation.
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