Nickel & Cobalt Alloys

N06625 Supply Detail

Category

  • Bar and Rod

  • Plate and Sheet

  • Strip

  • Pipe and Tube

  • Wire

  • Welding

  • Powder Material

  • Cast Products

  • Forged Products

  • Fittings

  • Fastening

    Forms & Sizes

    Round Bar:
    φ2–500 mm, 1–6 m length

    Flat/Square Bar:
    4–100 mm thickness/width

    Hex Bar:
    A/F 3–100 mm

    Hollow Bar:
    OD 20–300 mm

    Forms & Sizes

    Sheet:
    0.3–6 mm thickness

    Medium Plate:
    6–25 mm thickness

    Heavy Plate:
    25–100 mm thickness

    Forms & Sizes

    Standard Strip:
    0.05–3 mm thick,
    10–600 mm wide

    Precision strip:
    0.01–0.5 mm thick,
    tight tolerance ±0.005 mm

    Foil:
    0.005–0.1 mm thick

    Forms & Sizes

    Seamless Tube:
    OD 6–450 mm,
    WT 1–50 mm,
    1–12 m length

    Welded Tube:
    OD 10–600 mm,
    WT 1–20 mm

    Capillary Tube:
    OD 1–10 mm,
    WT 0.1–2 mm

    Forms & Sizes

    Wire Form:
    Cold Drawn Wire,
    Bright Wire,
    Spring Wire,
    Fine Wire,
    Ultra-fine Wire

    General Diameter:
    φ0.1–10 mm

    Coil Weight:
    50–500 kg,
    customizable tolerance

    Forms & Sizes

    Solid Wire:
    φ0.8–4.0 mm

    Flux-cored Wire:
    φ1.2–4.0 mm

    Welding Rod:
    φ2.0–5.0 mm

    Forms & Sizes

    Powder Form:
    AM 3D Printing Powder,
    Spherical Powder,
    Gas-atomized Powder,
    Water-atomized Powder

    Particle Size:
    10–150 μm

    Sphericity:
    ≥90% for AM grade

    Forms & Sizes

    Cast Ingot:
    φ200–800 mm

    Precision Casting:
    min wall 0.5 mm

    Cast Pipe:
    OD 100–600 mm,
    WT 10–50 mm

    Forms & Sizes

    Forged Bar:
    Φ35–500 mm

    Forged Ring:
    OD 200–2000 mm

    Forging Weight:
    1–5000 kg

    Forms & Sizes

    Fittings Form:
    Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint

    Size range:
    1/2''–24'' (DN15–DN600)

    Wall thickness:
    Sch10–Sch160, STD, XS, XXS

    Pressure Class:
    150–2500 LB

    Forms & Sizes

    Fastening Form:
    Bolt, Nut, Screw, Stud, Washer, Pin, Rivet

    Metric: M3–M64

    Imperial: #4–2.5''

    Length: 6–500 mm

N06625 Product Description

Overview

N06625 is a nickel–chromium–molybdenum alloy with niobium additions, used for its high strength, excellent fabricability (including joining), and outstanding corrosion resistance. Service temperatures range from cryogenic to 982 °C (1800 °F). This datasheet presents the material within the American (ASTM / ASME / SAE-AMS / UNS) standard system.

Its strength derives from the stiffening effect of molybdenum and niobium on the nickel–chromium matrix, so precipitation-hardening treatments are not required. This same combination of elements gives superior resistance to a wide range of severe corrosive environments, as well as to high-temperature oxidation and carburisation. The high molybdenum content makes the alloy very resistant to pitting and crevice corrosion, while niobium stabilises it against sensitisation during welding; the high nickel content provides freedom from chloride-ion stress-corrosion cracking.

These properties make the alloy an excellent choice for sea-water and chemical-processing applications, aerospace ducting and engine-exhaust systems, and nuclear reactor-core and control-rod components. It offers freedom from local attack, high corrosion-fatigue strength, high tensile strength, and excellent weldability and brazeability across its full service range.

1. Physical Properties

Typical values per Special Metals official datasheet, annealed condition.

Property Value Unit
Density 8.44 g/cm³
Melting range 1290–1350 °C
Elastic modulus (21 °C, annealed) 207.5 GPa
Shear modulus (21 °C, annealed) 81.4 GPa
Poisson's ratio (21 °C) 0.278
Specific heat capacity (21 °C) 410 J/kg·K
Electrical resistivity (21 °C) 1.29 µΩ·m
Thermal conductivity (21 °C) 9.8 W/m·K
Coefficient of thermal expansion (21–93 °C) 12.8 µm/m·°C
Magnetic permeability (200 Oe) 1.0006 Essentially non-magnetic
Curie temperature <–196 °C
Maximum service temperature ~982 °C

2. Chemical Composition (Limiting, wt %)

Limiting composition per ASTM B443 / B446 (UNS N06625).

Element Symbol Min % Max % Role in Alloy
Nickel (+ Cobalt) Ni 58.0 balance Austenitic FCC matrix; chloride SCC resistance
Chromium Cr 20.0 23.0 Forms Cr₂O₃ scale; oxidation and corrosion resistance
Molybdenum Mo 8.0 10.0 Solid-solution strengthening; pitting/crevice resistance
Niobium (+ Tantalum) Nb 3.15 4.15 Matrix stiffening; stabilises against weld sensitisation
Iron Fe 5.0 Residual
Carbon C 0.10 Controlled
Manganese Mn 0.50 Deoxidiser
Silicon Si 0.50 Deoxidiser
Aluminium Al 0.40 Residual; deoxidiser
Titanium Ti 0.40 Residual; carbide former
Cobalt Co 1.0 Residual (if determined)
Phosphorus P 0.015 Residual impurity
Sulphur S 0.015 Residual impurity

3. Mechanical Properties

Nominal room-temperature properties (composites for product sizes up to 4 in; not for specification purposes).

Form / Condition Tensile strength Yield strength (0.2%) Elongation Hardness
Rod/Bar/Plate, As-Rolled 827–1103 MPa 414–758 MPa 30–60 % 175–240 HB
Rod/Bar/Plate, Annealed 827–1034 MPa 414–655 MPa 30–60 % 145–220 HB
Rod/Bar/Plate, Solution-Treated 724–896 MPa 290–414 MPa 40–65 % 116–194 HB
Sheet/Strip, Annealed 827–1034 MPa 414–621 MPa 30–55 % 145–240 HB
Tube/Pipe, Annealed 827–965 MPa 414–517 MPa 30–55 %

Low-temperature ductility and toughness are retained to –196 °C. Values are typical; confirm against the mill test certificate for each delivery.

4. Corrosion and High-Temperature Resistance

Environment Performance Notes
Sea water Outstanding Freedom from pitting and crevice attack; high corrosion-fatigue strength
Chloride stress-corrosion cracking Outstanding High Ni content gives immunity
Pitting and crevice corrosion Outstanding High Mo content
Oxidising acids Excellent Ni + Cr resist oxidising chemicals
Non-oxidising / reducing acids Excellent High Ni + Mo content
Mixed acids (e.g. HCl + HNO₃) Excellent Resists directly opposite corrosion types
High-temperature oxidation Good Protective oxide retained; scaling significant above ~982 °C
Carburisation Good Resists high-temperature carburisation
Weld sensitisation Excellent Nb stabilises against intergranular attack

5. Heat Treatment

The alloy is matrix-stiffened, not precipitation-hardened; heat treatment is for annealing, stress relief, and solution treatment only.

Anneal Temperature: 927–1038 °C (1700–1900 °F), time commensurate with thickness Purpose: Softening and recrystallisation; recommended for service at 650 °C and below, and for fatigue/tensile-critical applications.

Solution Treatment Temperature: 1093–1204 °C (2000–2200 °F) Purpose: Optimum creep-rupture resistance for service above 650 °C.

Stress Relief Heating cold-drawn material at 595–760 °C reduces residual stress; virtually complete at 871 °C. Cooling rate has no significant effect on properties.

6. Weldability and Joining

Readily joined by conventional welding processes. Matching filler metals are highly resistant to corrosion and oxidation and require no post-weld heat treatment to maintain strength and ductility from cryogenic to 982 °C. Niobium stabilisation prevents weld-zone sensitisation.

Welding Process Applicability Filler / Consumable
GTAW / TIG Excellent AWS A5.14 ERNiCrMo-3 (Filler Metal 625)
GMAW / MIG Excellent AWS A5.14 ERNiCrMo-3 (Filler Metal 625)
SMAW / stick Excellent AWS A5.11 ENiCrMo-3 (Electrode 112)

The filler metals are also used as "overmatching" products for joining 316/317 stainless, 6 % Mo super-austenitic stainless, and other Ni-Cr-Mo alloys.

7. Machinability and Fabrication

Machining Guidelines

Tooling Surface Speed Feed
High-speed steel 4.0–10.7 m/min 0.13–0.51 mm/rev
Coated carbide 14–34 m/min 0.13–0.51 mm/rev

Forming Processes

Process Notes
Hot forming Heat to (not above) 1175 °C; heavy forging 1175→1010 °C; light reductions down to 925 °C; 15–20 % minimum reductions
Cold forming Standard processes; high work-hardening rate; tensile >2000 MPa achievable in fine wire after 75–90 % reduction
Annealing between operations 927–1038 °C

8. Applications

Industry Typical Components Key Requirements
Marine Mooring cables, propeller blades, exhaust ducts, undersea cable sheathing, submarine fittings Sea-water pitting/crevice resistance; chloride SCC immunity
Aerospace Ducting, engine-exhaust and thrust-reverser systems, honeycomb structures, bellows, turbine shroud rings High strength + oxidation + thermal-fatigue resistance
Chemical processing Reaction vessels, distillation columns, heat exchangers, transfer piping, valves, bubble caps Broad-spectrum corrosion resistance
Nuclear Reactor-core and control-rod components Strength + pitting/SCC resistance in 260–316 °C water
Power generation High-temperature tubing, bellows, seals Allowable design strength at 649–760 °C

9. Available Product Forms and Standards (ASTM / AMS System)

Product Form ASTM Standard ASME Code AMS Standard
Rod and bar ASTM B446 ASME SB-446 AMS 5666
Forgings ASTM B564 ASME SB-564 AMS 5666
Wire AMS 5837
Plate, sheet and strip ASTM B443 ASME SB-443 AMS 5599 / 5869
Seamless pipe and tube ASTM B444 / B829 ASME SB-444 / SB-829 AMS 5581
Welded pipe / tube ASTM B705 / B751 ASME SB-705 / SB-751
Fittings ASTM B366 ASME SB-366
Welding consumables AWS A5.14 ERNiCrMo-3 · AWS A5.11 ENiCrMo-3

ASME Boiler and Pressure Vessel Code approved (Section VIII Div. 1: Grade 1 to 649 °C, Grade 2 to 871 °C); listed in NACE MR0175.

10. Comparison with Related Alloys (UNS System)

UNS Ni % Cr % Mo % UTS (annealed) Max Temp. Best Used For
N06625 ≥58 20–23 8–10 827–1034 MPa ~982 °C Sea-water; chemical processing; universal corrosion
N06600 ≥72 14–17 ~655 MPa ~1095 °C General high-temp; carburisation/nitriding
N06601 58–63 21–25 ~550 MPa ~1250 °C(ox) Cyclic oxidation; radiant tubes
N06617 44.5 20–24 8–10 ~734 MPa ~1100 °C Gas-turbine hot section; creep strength
N07718 50–55 17–21 2.8–3.3 ~1240 MPa(aged) ~650 °C High-strength age-hardenable structures
N08825 38–46 19.5–23.5 2.5–3.5 ~690 MPa ~540 °C Acid resistance; Fe-Ni-Cr-Mo economy grade

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