Nickel & Cobalt Alloys

Hastelloy C 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

Hastelloy C Product Description

Overview

Hastelloy C is the original nickel–molybdenum–chromium–tungsten corrosion-resistant alloy of the "C" family — the forerunner of the modern C-type alloys (C-276, C-22, C-4, C-2000). This datasheet presents the material within the trade-name designation system.

It combines resistance to both oxidising and reducing acids, performing well in sulphuric, phosphoric and chlorine-contaminated acids, with significantly greater resistance to chloride stress-corrosion cracking than stainless steels. The high molybdenum content provides resistance to pitting and crevice corrosion, while the chromium content gives resistance in oxidising media — a combination that made it popular for chemical reactors, evaporators and transfer piping.

Important note: the original alloy C has relatively high carbon and silicon contents, which can lead to carbide precipitation in the weld heat-affected zone and reduced corrosion resistance in as-welded structures. For this reason it has been largely superseded by the low-carbon, low-silicon alloy C-276 (with a small tungsten addition) for as-welded service, and by alloy C-22 (higher chromium) for oxidising media. For new fabrications, C-276 or C-22 are normally specified; original alloy C is presented here for reference and legacy applications.

1. Physical Properties

Typical values, solution-annealed condition (representative of the C family).

Property Value Unit
Density 8.7–8.9 g/cm³
Melting range 1325–1370 °C
Young's modulus (20 °C) ~205 GPa
Magnetic response Non-magnetic
Coefficient of thermal expansion Low (vs stainless)
Hardness (solution-annealed) 88–96 HRB
Structure Austenitic (FCC)

2. Chemical Composition (Nominal, wt %)

Nominal composition per ASTM B574 (C-family).

Element Symbol Value Role in Alloy
Nickel Ni Balance Base element; corrosion resistance
Molybdenum Mo 15–17 Pitting/crevice + reducing-acid resistance
Chromium Cr 15–16 Oxidising-media resistance; passive film
Iron Fe 4–7 Present
Tungsten W 3–4.5 Localised-corrosion resistance
Cobalt Co ≤2.5 Residual
Carbon C ~0.04–0.08 Higher than C-276 (HAZ sensitisation risk)
Silicon Si ~0.5–1.0 Higher than C-276
Manganese Mn ≤1.0 Deoxidiser
Vanadium V ~0.2–0.4 Carbide former

Note: the higher carbon and silicon (vs alloy C-276) are the reason this original grade is prone to weld HAZ attack.

3. Mechanical Properties

Typical room-temperature properties, solution-annealed condition.

Property Value Source
Ultimate tensile strength 690–785 MPa C-family representative
0.2% proof strength (yield) 280–355 MPa C-family representative
Elongation at break 40–50 % C-family representative
Hardness 88–96 HRB Solution-annealed

The alloy is solid-solution-strengthened (not age-hardenable). Values are representative of the C family; for specification purposes use the modern grade (C-276) data and mill test certificate.

4. Corrosion Resistance

Environment Performance Notes
Oxidising + reducing acids Excellent Combined Cr (oxidising) + Mo (reducing)
Sulphuric / phosphoric acid Excellent Strong acid resistance
Chlorine-contaminated acids Very Good Mo + W content
Pitting / crevice corrosion Very Good High molybdenum content
Chloride SCC Very Good Far better than stainless steels
Weld HAZ (as-welded) Caution Higher C/Si than C-276 — prone to HAZ carbide precipitation
Oxidising media (strong) Good Better served by higher-Cr alloy C-22

5. Heat Treatment

A solid-solution Ni-Cr-Mo-W alloy; not age-hardenable. Heat treatment is solution annealing only.

Solution Anneal Temperature: ~1200–1230 °C, followed by rapid cooling (water quench) Purpose: dissolves carbides/secondary phases, restores corrosion resistance and ductility.

Service caution: the higher carbon/silicon of the original grade promotes carbide precipitation in the weld HAZ; a post-weld solution anneal is advisable for aggressive service, or specify low-carbon alloy C-276 for as-welded use.

6. Weldability and Joining

Weldable, but the original alloy C has a higher carbon and silicon content than C-276, so the weld heat-affected zone is susceptible to carbide precipitation and reduced corrosion resistance. A post-weld solution anneal is recommended for aggressive acid service; for as-welded service the low-carbon alloy C-276 should be specified.

Welding Process Applicability Filler / Consumable
GTAW / TIG Good (PWHT advised) AWS A5.14 ERNiCrMo-4 (alloy C-276 type) matching filler
GMAW / MIG Good (PWHT advised) AWS A5.14 ERNiCrMo-4 (alloy C-276 type) matching filler
SMAW / stick Good (PWHT advised) AWS A5.11 ENiCrMo-4 type electrode

Keep joints clean; solution-anneal welded assemblies destined for severe corrosion service.

7. Machinability and Fabrication

Machining Guidelines

Parameter Recommendation
Work hardening High rate (typical of Ni-Cr-Mo alloys); rigid setup, sharp tooling, positive rake
Cutting Low speed, sufficient feed/depth to cut below work-hardened layer
Coolant Ample flood coolant
Preferred condition Solution-annealed

Forming Processes

Process Notes
Hot forming ~950–1230 °C; solution-anneal after hot forming
Cold forming Cold-formable; high work-hardening rate; solution-anneal after heavy reductions
Post-fabrication Solution-anneal welded/heavily-worked parts for severe-service corrosion resistance

8. Applications

Industry Typical Components Key Requirements
Chemical processing Reactors, evaporators, transfer piping Mixed oxidising/reducing acid resistance
Sulphuric / phosphoric acid Process vessels and piping Strong-acid resistance
Chlorine / chlorinated media Process equipment Pitting/crevice + Cl resistance
Legacy / replacement Existing alloy-C installations Compatibility with original-C components

Note: for new equipment, alloy C-276 (as-welded service) or C-22 (oxidising media) are normally the preferred current-production choices.

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

Product Form ASTM Standard ASME Code
Rod and bar ASTM B574 ASME SB-574
Plate, sheet and strip ASTM B575 ASME SB-575
Seamless pipe and tube ASTM B622 ASME SB-622
Welded pipe ASTM B619 ASME SB-619
Welded tube ASTM B626 ASME SB-626
Fittings ASTM B366 ASME SB-366
Welding consumables AWS A5.14 ERNiCrMo-type matching filler

Note: standards listed are those of the C-family Ni-Cr-Mo-W alloys; original alloy C is largely superseded by alloy C-276 (UNS N10276).

10. Comparison with Related Alloys (Hastelloy Trade-Name System)

Hastelloy Grade Ni % Cr % Mo % Other Best Used For
Hastelloy C bal 15–16 15–17 W 3–4.5, C ~0.04–0.08 Original C-family (largely superseded)
Hastelloy C-276 bal 14.5–16.5 15–17 W 3–4.5, C ≤0.01 Low-C/Si; as-welded mixed-acid service
Hastelloy C-22 bal 20–22.5 12.5–14.5 W 2.5–3.5 Higher Cr; best pitting/crevice, oxidising
Hastelloy C-4 bal 14–18 14–17 Ti, low Fe/W Thermal stability; SCC resistance
Hastelloy C-2000 bal 22–24 15–17 Cu 1.6 Most versatile; Cu for reducing acids

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