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| Attribute | Specification |
|---|---|
| Grade | Incoloy 925 / Alloy 925 / UNS N09925 |
| Standard | ASTM B805, ASME SB805, ASTM B637, ASTM B564, NACE MR0175 / ISO 15156-3 |
| Delivery Condition | Solution annealed; solution annealed + aged (precipitation hardened); hot rolled / forged; cold drawn |
| Surface Condition | Black, pickled, peeled / turned, centreless ground, polished, bright ground (Ra 1.6 um max) |
| Size Range | Round Dia 6 - 800 mm, Flat 5 - 300 mm thick, Strip 0.5 - 6 mm, Wire Dia 0.5 - 60 mm |
| Certification | ISO 9001, EN 10204 3.1 / 3.2 MTC, PMI, UT, NACE sour service test report |
Incoloy 925 (UNS N09925, W.Nr 2.4858) is an age-hardenable nickel-iron-chromium alloy with controlled additions of molybdenum, copper, titanium and aluminium. Its base chemistry is derived from Incoloy 825, so it keeps that grade's resistance to reducing acids, pitting, crevice attack and chloride stress corrosion cracking. Titanium and aluminium add a gamma-prime Ni3(Al,Ti) precipitation reaction during ageing, which roughly doubles the yield strength compared with the non-hardenable 825 grade. Nickel at 42 - 46% gives immunity to chloride-induced SCC, molybdenum and copper handle reducing media and sour condensate, and chromium covers oxidising environments.
The alloy is selected where high mechanical load and aggressive media occur at the same time. Principal industries are oil and gas (sour downhole and wellhead equipment), marine and offshore engineering, chemical and petrochemical processing, power generation with flue gas desulphurisation, geothermal production and desalination. FUSHUN METAL produces Incoloy 925 round bar to ASTM B805 / ASME SB805 and ASTM B637, qualifies every heat lot to NACE MR0175 / ISO 15156-3 for H2S service, and releases material with EN 10204 3.1 certification under an ISO 9001 quality system.
Designations covering the same UNS N09925 chemistry:
| Standard System | Designation | Scope |
|---|---|---|
| UNS | N09925 | Primary material designation |
| ASTM / ASME | B805 / SB805, B637, B564, B983 | Bar, wire, forgings, flanges, plate and strip |
| EN / DIN | W.Nr 2.4858 | European Werkstoffnummer |
| JIS | NCF 925 | Japanese industrial standard |
| GOST | 03KHN45TYUB (type) | Russian equivalent reference |
| GB | NS2401 / H09925 | Chinese national standard |
| ISO / NACE | ISO 15156-3 (MR0175) | Sour service qualification, aged condition |
| ASME | Code Case 2218 | Section VIII Div.1 pressure vessels |
No dedicated AMS aerospace sheet is issued for Alloy 925; aerospace and defence enquiries are handled under ASTM B805 with customer source specification.
Comparable alloys frequently cross-checked against Incoloy 925 during material selection:
| Alloy | UNS | ASTM | AMS | EN / DIN | JIS |
|---|---|---|---|---|---|
| Incoloy 825 | N08825 | B425 | - | 2.4858 | NCF 825 |
| Inconel 718 | N07718 | B637 | 5662 | 2.4668 | NCF 718 |
| Inconel 725 | N07725 | B805 | - | - | - |
| Incoloy 945 | N09945 | - | - | - | - |
| Monel K-500 | N05500 | B865 | 4676 | 2.4375 | - |
| 17-4PH | S17400 | A564 | 5643 | 1.4542 | SUS 630 |
FUSHUN METAL keeps all six of these families in the same melting and stock programme, so a downgrade or upgrade can be quoted from one heat-lot traceability chain.
Packer bodies and mandrels, landing nipples, tubing hangers, tool joints, subsurface safety valve bodies, side pocket mandrels, flow control choke trim and choke bodies, wireline tool bodies, Christmas tree and wellhead flanges, stud bolts and heavy hex nuts, valve stems, gate valve trim, drill collar subs, completion tubing couplings.
Propeller shafts, pump shafts, seawater pump casings and impeller shafts, subsea connector bodies, riser flange bolting, rudder stock, hatch and hull fasteners, mooring system hardware, ROV tooling shafts, seawater lift pump column shafts.
Heat exchanger tubesheets, channel and shell flanges, reactor agitator shafts, scrubber internals and support grids, sulphuric and phosphoric acid piping flanges, valve trim, springs and fasteners in acid service, caustic soda evaporator components, pickling line hooks and racks.
Flue gas desulphurisation absorber tower bolting, steam turbine casing studs, feedwater heater fasteners, geothermal wellhead studs and flanges, brine heater tube supports.
Digester fittings, evaporator tube support plates, high pressure membrane housing end caps, instrument and control valve stems. FUSHUN METAL machines test coupons from the actual delivered bar, not from separate sample stock, so reported properties always match the shipped heat.
| Product Form | Size Range | Condition |
|---|---|---|
| Hot rolled round bar | Dia 6 - 500 mm | Annealed / annealed + aged |
| Forged round bar | Dia 150 - 800 mm | Annealed / annealed + aged |
| Peeled, turned, ground round bar | Dia 20 - 300 mm, tolerance h9 / h11 | Annealed / annealed + aged |
| Cold drawn round bar and wire | Dia 0.5 - 60 mm | Annealed / cold drawn |
| Rolled flat bar | Thickness 5 - 300 mm, width 20 - 800 mm | Annealed / aged |
| Square bar and hex bar | 10 - 200 mm across flats | Annealed / aged |
| Strip and coil | Thickness 0.5 - 6 mm, width 10 - 600 mm | Annealed |
| Billet and forging stock | Section up to 900 mm, cut to length | As forged / annealed |
Lengths are 1,000 - 6,000 mm as standard and up to 12,000 mm on request. FUSHUN METAL offers fixed-length sawing, chamfering, rough turning and third-party witnessed cutting. Non-standard diameters outside the table are rolled to order from 3 tonnes. Ground and polished bars are supplied at roughness Ra 1.6 um maximum and straightness within 1 mm per metre.
Composition per ASTM B805 / UNS N09925, weight percent. FUSHUN METAL verifies each element by optical emission spectrometry per heat and confirms finished bars by positive material identification.
| Element | Ni | Cr | Fe | Mo | Cu | Ti | Al | Mn | Si | Nb | C | S | P |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Min | 42.0 | 19.5 | 22.0 | 2.5 | 1.5 | 1.9 | 0.1 | - | - | - | - | - | - |
| Max | 46.0 | 22.5 | Bal. | 3.5 | 3.0 | 2.4 | 0.5 | 1.0 | 0.5 | 0.5 | 0.03 | 0.03 | 0.03 |
| Condition | Tensile Strength | Yield 0.2% | Elongation | Reduction of Area | Hardness | Impact |
|---|---|---|---|---|---|---|
| Solution annealed, min | 760 MPa / 110 ksi | 345 MPa / 50 ksi | 30% | 40% | 32 HRC max | - |
| Solution annealed, typical | 685 - 860 MPa | 271 - 550 MPa | 40 - 56% | 45% | 76 HRB | - |
| Annealed + aged, min | 965 MPa / 140 ksi | 758 MPa / 110 ksi | 18% | 25% | 25 - 38 HRC | 47 J at -60 C |
| Annealed + aged, typical | 1030 - 1170 MPa | 790 - 895 MPa | 20 - 25% | 30 - 45% | 32 - 35 HRC | 47 - 60 J |
Physical data: density 8.08 g/cm3, melting range 1311 - 1366 C, elastic modulus 190 - 199 GPa at 21 C, thermal expansion 13.2 x 10-6 /C from 20 to 100 C, PREN minimum 40. Aged bars retain useful strength to about 540 C; the NACE MR0175 hardness ceiling of 35 - 38 HRC is the controlling value for sour service release, and FUSHUN METAL records it on every line of the certificate.
Melting. FUSHUN METAL melts Alloy 925 by vacuum induction melting or by electric arc furnace with AOD refining, ladle furnace treatment and vacuum degassing. ESR or VAR remelting is available for downhole and subsea orders that require lower inclusion content and tighter segregation control. Revert material is restricted and fully traceable.
Hot working. Ingots and billets are forged and rolled between 870 and 1175 C with controlled reduction per pass and documented reheat cycles, holding the grain structure fine and uniform through the section. Bars above 150 mm are upset forged to break up centre porosity.
Heat treatment. Solution annealing and ageing run in calibrated furnaces surveyed to AMS 2750, with charge and load thermocouples. Chart traces and pyrometry records are retained for five years and attached to the heat file.
Inspection. Every heat is checked by optical emission spectrometry, and every finished bar by positive material identification. Mechanical testing follows ASTM E8 / E8M for tensile and ASTM E18 for hardness, with Charpy V-notch at -60 C on request. Ultrasonic examination to ASTM A388 or SEP 1921 class C/c, grain size to ASTM E112, liquid penetrant to ASTM E165 and intergranular corrosion to ASTM G28 Method A are available. Dimensional and straightness checks are recorded before release.
Certification. FUSHUN METAL operates an ISO 9001 certified quality management system. Standard documentation is EN 10204 3.1; EN 10204 3.2 with third-party witness from SGS, TUV, BV or DNV can be arranged. Each bar carries the heat number, specification, UNS designation and delivery condition for full traceability from melt to shipment.
