Super Stainless Steel

Alloy 2304 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

Alloy 2304 Product Description

Overview

Alloy 2304 is a molybdenum-free lean ferritic-austenitic (duplex) stainless steel, with a microstructure of roughly equal ferrite and austenite. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.

With about 23% chromium, 4% nickel and 0.10% nitrogen and no deliberate molybdenum addition, S32304 offers general corrosion resistance comparable to 316L together with yield strength roughly twice that of 304/316 austenitic grades, allowing weight savings in properly designed applications. The low nickel and high chromium contents give improved resistance to chloride stress-corrosion cracking relative to 304 and 316. It is suited to the −50 °C to +300 °C temperature range.

Typical applications include storage tanks, pressure vessels, structural and architectural components, water and wastewater treatment, pulp-and-paper equipment, and concrete reinforcement bar in aggressive environments.

1. Physical Properties

Property Value Unit
Density 7.8 g/cm³
Melting range 1385–1450 °C
Elastic modulus 200 GPa
Coefficient of thermal expansion (20–100 °C) 13 µm/m·°C
Thermal conductivity (20 °C) 15 W/m·K
Maximum operating temperature ~300 °C
Structure Ferritic-austenitic (duplex)

2. Chemical Composition (wt %)

Element Symbol Min % Max % Role in Alloy
Iron Fe Balance Base element
Chromium Cr 21.5 24.5 Ferrite former; corrosion resistance
Nickel Ni 3.0 5.5 Austenite former; phase balance
Molybdenum Mo 0.05 0.60 Residual (molybdenum-free grade)
Copper Cu 0.05 0.60 Residual
Nitrogen N 0.05 0.20 Austenite former; strength; pitting
Manganese Mn 2.50 Deoxidiser
Silicon Si 1.00 Deoxidiser
Carbon C 0.030 Low (intergranular resistance)
Phosphorus P 0.040 Residual impurity
Sulphur S 0.030 Residual impurity

3. Mechanical Properties

Solution-annealed condition, per ASTM A240 for UNS S32304.

Condition Property Value
Solution-annealed Tensile strength (UTS) ≥600 MPa
Solution-annealed 0.2% yield strength ≥400 MPa
Solution-annealed Elongation at break ≥25 %
Solution-annealed Hardness ≤290 HB
Elastic modulus 200 GPa

Confirm against the mill test report.

4. Corrosion Resistance

Environment Performance Notes
General corrosion Very Good Comparable to 316L
Chloride stress-corrosion cracking Very Good Superior to 304 / 316 (ferrite phase)
Pitting and crevice corrosion Good PREN ~24–26
Erosion / corrosion fatigue Very Good High strength
Seawater / sour (H₂S) Limited Not recommended for aggressive chlorides / sour service

5. Heat Treatment

Not hardenable by heat treatment; properties are set by solution annealing and phase balance.

Solution Anneal Approximately 1020–1100 °C followed by rapid cooling (water quench) to retain the balanced ferrite-austenite structure and avoid embrittling intermetallic phases. Avoid prolonged exposure in the 350–950 °C range (sigma-phase / 475 °C embrittlement); do not use above ~300 °C in service.

6. Weldability and Joining

Good weldability with correct procedures; use a matching lean-duplex or 23 7 N-type filler and control heat input to maintain phase balance.

Welding Process Applicability Filler / Consumable
GTAW / TIG Good Lean-duplex (23 7 N type) or ER2209
GMAW / MIG Good Lean-duplex or ER2209
SMAW / stick Good Matching duplex electrode

No preheat; control interpass temperature and heat input to maintain phase balance.

7. Machinability and Fabrication

Machining Guidelines

Parameter Recommendation
Machinability Good for a duplex; rigid setup, carbide tools, moderate speeds
Work hardening Significant; positive feeds, avoid dwelling
Coolant Ample flood coolant

Forming Processes

Process Notes
Cold forming Higher forces than austenitics (high duplex strength)
Hot forming ~1150–950 °C; solution anneal + quench afterward

8. Applications

Industry Typical Components Key Requirements
Storage / containment Tanks, pressure vessels, silos Strength + SCC resistance, low cost
Construction Structural sections, rebar, facades High strength-to-weight
Water / municipal Wastewater treatment, water tanks Chloride resistance
Pulp & paper Process equipment Chloride + caustic resistance

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

Product Form ASTM Standard ASME Code
Plate, sheet and strip ASTM A240 ASME SA-240
Bar and shapes ASTM A276 / A479 ASME SA-479
Seamless / welded tube ASTM A789 ASME SA-789
Seamless / welded pipe ASTM A790 ASME SA-790
Fittings ASTM A815 ASME SA-815
Sour service NACE MR0175 / ISO 15156

Molybdenum-free lean ferritic-austenitic (duplex) stainless steel. UNS S32304.

10. Comparison with Related Alloys (Alloy Designation System)

Alloy Cr % Ni % Mo % N % Best Used For
Alloy 2304 21.5–24.5 3.0–5.5 0.05–0.60 0.05–0.20 Lean Mo-free duplex; 316L substitute
Alloy 2101 21–22 1.35–1.70 0.10–0.80 0.20–0.25 Lean low-Ni duplex
Alloy 2205 21–23 4.5–6.5 2.5–3.5 0.08–0.20 Standard duplex
Alloy 304L 18–20 8–12 Austenitic general service
Alloy 316L 16–18 10–14 2.0–3.0 Austenitic, chloride service

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