Nickel & Cobalt Alloys

2.4633 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

2.4633 Product Description

Overview

2.4633 is a high-carbon nickel–chromium–iron alloy with deliberate additions of aluminium (1.8–2.4%) and the reactive elements yttrium and zirconium. The "CA" denotes its defining metallurgy: a self-healing alumina (Al₂O₃) surface layer combined with grain-boundary reinforcement by stable chromium carbides (M₂₃C₆ / M₇C₃). This datasheet presents the material within the European (DIN / EN / Werkstoff-Nummer) standard system.

It is among the most oxidation-resistant and creep-resistant wrought nickel alloys commercially available, with excellent service capability up to 1200 °C (2192 °F) even under cyclic heating and cooling. The tightly adhering alumina scale resists spalling, giving the alloy the lowest mass loss under cyclic oxidation of common high-temperature materials. The high carbon content and carbide precipitation give outstanding high-temperature creep strength.

The alloy is not age-hardened in the conventional sense; it is supplied solution-annealed (typically at 1220 °C to develop a coarse grain size ≥70 µm for maximum creep strength). It offers very good resistance in carburising and oxidising/chlorinating media and good resistance in sulphur-containing oxidising atmospheres. Note: solution-annealed material is sensitive to stress-relaxation cracking between 600–750 °C and should be stabilisation-annealed for long-term service in that range.

1. Physical Properties

Values per VDM Metals official Material Data Sheet No. 4137 (Rev. 04, 2022), solution-annealed condition.

Property Value Unit
Density (25 °C) 7.93 g/cm³
Melting range 1340–1400 °C
Elastic modulus (20 °C) 215 GPa
Thermal conductivity (20 °C) 10.4 W/m·K
Coefficient of thermal expansion (20–100 °C) 14.15 µm/m·°C
Specific heat capacity (20 °C) 447 J/kg·K
Electrical resistivity (20 °C) 1.23 µΩ·m
Magnetic permeability (20 °C) 1.01 max Essentially non-magnetic
Maximum service temperature (oxidation) ~1200 °C
Crystal structure Face-centred cubic (FCC)

2. Chemical Composition (Limiting, wt %)

Composition per EN 10302 (W.Nr. 2.4633, NiCr25FeAlY).

Element Symbol Min % Max % Role in Alloy
Nickel Ni Balance Austenitic FCC matrix
Chromium Cr 24.0 26.0 Oxidation resistance
Iron Fe 8.0 11.0 Balance element
Aluminium Al 1.8 2.4 Oxidation resistance (alumina-forming)
Carbon C 0.15 0.25 Carbide strengthening (creep)
Titanium Ti 0.1 0.2 Carbide former
Zirconium Zr 0.01 0.1 Grain-boundary strengthening
Yttrium Y 0.05 0.12 Oxide-scale adherence (rare earth)
Silicon Si 0.5 Deoxidiser
Manganese Mn 0.5 Deoxidiser
Copper Cu 0.1 Residual
Phosphorus P 0.02 Residual impurity
Sulphur S 0.01 Residual impurity

Nominal: Ni-25Cr-9.5Fe-2Al-Y. The high carbon (0.15-0.25%), aluminium and yttrium give exceptional creep strength and oxidation resistance to ~1200 °C.

3. Mechanical Properties

Solution-annealed (+AT) condition, per EN 10302 for W.Nr. 2.4633.

Property Value Unit
Tensile strength (Rm) ≥680 MPa
0.2% proof strength (Rp0.2) ≥270 MPa
Elongation at fracture (A) ≥30 %

Values per EN 10302 (creep-resisting alloys). Confirm against the inspection certificate (EN 10204).

4. Creep and High-Temperature Strength

Typical long-term creep values, solution-annealed (1220 °C), per VDM Material Data Sheet No. 4137.

Temperature Creep strength Rm/10⁴ h Creep strength Rm/10⁵ h
650 °C 215 MPa 140 MPa
700 °C 155 MPa 100 MPa
800 °C 42 MPa 20 MPa
900 °C 18 MPa 9.7 MPa
1000 °C 9.0 MPa 4.5 MPa
1100 °C 4.4 MPa 2.1 MPa
1200 °C 2.2 MPa 0.8 MPa

The outstanding creep strength derives from primary M₂₃C₆ / M₇C₃ carbide precipitation, which is the primary reason for selecting this alloy over Alloy 600 / 601 in load-bearing furnace components above 1000 °C.

5. Oxidation and Corrosion Resistance

Environment Performance Notes
High-temperature oxidation (air) Outstanding Adherent Al₂O₃ scale; service to 1200 °C; better than Alloy 601 across the whole range
Cyclic oxidation Outstanding Lowest mass loss of common high-temperature alloys under cyclic stress
Carburisation Excellent High Cr + Al; better than Alloy 601
Metal dusting Very Good Improved resistance vs Alloy 601
Oxidising sulphur-containing atmospheres Very Good Cr + Al provide resistance at elevated temperature
Oxidising / chlorinating media Very Good Good resistance reported by manufacturer
Reducing, low-oxygen atmospheres Limited Alumina scale requires oxidising conditions to self-heal

6. Heat Treatment

Supplied in the solution-annealed state. Not a conventional age-hardening alloy; strength derives from carbide precipitation and solution-annealed grain size.

Solution Anneal Temperature: 1220 °C Purpose: Develops coarse grain size (≥70 µm) for maximum creep strength. Retention time scales with section thickness; accelerated cooling (water or compressed air) if further processing follows.

Stabilisation Anneal Temperature: 950 °C, minimum 3 hours Purpose: Required before or after welding, and before long-term (>100 h) service in the 600–750 °C range, to prevent stress-relaxation cracking.

Hot working: 900–1200 °C, followed by rapid cooling; reheat if temperature falls below the lower limit. Post-forming heat treatment recommended.

7. Weldability and Joining

Weldable by conventional processes (TIG, plasma, GMAW). Owing to lower thermal conductivity and higher thermal expansion than carbon steel, use root gaps of 1–3 mm and included angles of 60–70°. Interpass temperature should not exceed 120 °C; stringer-bead technique recommended.

Welding Process Applicability Filler / Consumable
GTAW / TIG Excellent VDM FM 602 CA (W.Nr. 2.4649) / S Ni 6025
Plasma Excellent S Ni 6025 (NiCr25Fe10AlY)
GMAW / MAG Good DIN EN ISO 18274 S Ni 6025; multicomponent shielding gas

Stabilisation anneal at 950 °C may be required before/after welding for service in the 600–750 °C range. Preheating is generally not required.

8. Machinability and Fabrication

Machining Guidelines

Parameter Recommendation
Preferred condition Solution-annealed
Work hardening Higher than austenitic stainless; keep tool engaged at all times
Cutting speed Low cutting speed, moderate feed; cut below the strain-hardened zone
Coolant Ample water-based emulsion (as for stainless steels)

Forming Processes

Process Notes
Hot forming 900–1200 °C; rapid cool; reheat if below lower limit
Cold forming Higher work hardening than stainless; intermediate/solution anneal if deformation >7%
Bending Inner radius > 3× sheet thickness to avoid damage

9. Applications

Industry Typical Components Key Requirements
Thermal processing / heat treatment Radiant tubes, furnace muffles, rotary and shaft furnaces, kiln rollers, furnace installations Creep strength + cyclic oxidation resistance to 1200 °C
Chemical / petrochemical Reformers, methanol and ammonia synthesis, hydrogen production High-temperature strength + carburisation resistance
Power / energy Components for E-fuel syngas cooling, high-temperature ducting Creep and oxidation resistance
Automotive Exhaust system components, diesel glow plugs Cyclic oxidation resistance
Nuclear / waste Glass pots for melting radioactive waste Extreme-temperature stability

10. Available Product Forms and Standards (EN / DIN System)

Product Form DIN / EN Standard VdTÜV
Rod, bar DIN 17742 / 17752 · DIN EN 10302 VdTÜV-Wb 540
Sheet, plate DIN 17742 / 17750 · DIN EN 10302 VdTÜV-Wb 540
Strip DIN 17742 / 17750 · DIN EN 10302 VdTÜV-Wb 540
Wire DIN 17742
Welding consumable DIN EN ISO 18274 S Ni 6025

VdTÜV material data sheet 540: pressure-vessel approval from –10 to 1150 °C.

11. Comparison with Related Alloys (Werkstoff-Nummer System)

W.Nr. Ni % Cr % Fe % UTS (annealed) Max Temp. Best Used For
2.4633 bal 24–26 8–11 ≥675 MPa ~1200 °C Extreme oxidation + creep; furnace rolls, radiant tubes
2.4851 58–63 21–25 balance ≥550 MPa ~1250 °C(ox) Cyclic oxidation; radiant tubes
2.4816 ≥72 14–17 6–10 ~655 MPa ~1095 °C General high-temp; carburisation/nitriding
2.4856 ≥58 20–23 ≤5 ~830 MPa ~980 °C Universal corrosion resistance; seawater

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