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Haynes 25 (UNS R30605), historically known as L-605 / Stellite L-605, and covered in China as GH5605 (GH605), is a solid-solution strengthened cobalt-chromium-nickel-tungsten superalloy containing nominally 20% Cr, 10% Ni, 15% W, and 0.10% C. It is the baseline wrought cobalt alloy qualified to AMS 5537 (Sheet/Strip) and AMS 5759 (Bar/Forging), originally developed for post-WWII jet-engine combustor liners and still specified on legacy aircraft-engine drawings, high-temperature springs, and ASTM F90 implant devices.
Unlike precipitation-hardenable Ni-base alloys (Inconel 718, René 41), Haynes 25 derives strength only from W/Cr solute atoms and minor grain-boundary M₂₃C₆ / M₆C carbides. It cannot be age-hardened; high spring-temper strength is achieved by cold drawing. This article consolidates the exact chemical limits and mechanical property minima / typical values per AMS and producer data for design reference.
1. UNS, Trade Name & International Equivalents
|
System |
Designation |
Remark |
|---|---|---|
|
UNS (USA) |
R30605 |
— |
|
Trade Name |
Haynes® 25 / L-605 (Stellite L-605) |
Haynes International / Kennametal Stellite |
|
DIN / EN |
2.4964 / X40CoCrNiWNi22-20-15 (ref. EN 10095) |
Werkstoff-Nr. |
|
China (Aviation / GB) |
GH5605 (also GH605 in older docs) |
GJB 3165, HB 5497 |
|
AMS (Sheet/Strip) |
AMS 5537 |
Solution-annealed sheet & strip |
|
AMS (Bar/Forging) |
AMS 5759 |
— |
|
AMS (Weld Wire) |
AMS 5797 |
ERNiCoCrMo-1 or matching Co-base |
|
ASTM (Biomedical) |
ASTM F90 |
Implant-grade bar / wire |
2. Chemical Composition Requirements (AMS 5537 / AMS 5759)
|
Element |
Min % |
Max % |
Typical Heat Analysis |
Function |
|---|---|---|---|---|
|
Cobalt (Co) |
Balance |
Balance |
~47–51 |
Matrix; high-temp microstructural stability |
|
Chromium (Cr) |
19.00 |
21.00 |
20.0 |
Forms Cr₂O₃ protective scale (oxidation / sulfidation) |
|
Nickel (Ni) |
9.00 |
11.00 |
10.0 |
Stabilizes FCC γ-phase (lower than in Haynes 188) |
|
Tungsten (W) |
14.00 |
16.00 |
15.0 |
Principal solid-solution strengthener |
|
Carbon (C) |
0.05 |
0.15 |
0.08–0.11 |
Forms M₂₃C₆ / M₆C at grain boundaries |
|
Manganese (Mn) |
— |
1.50 |
0.6–1.0 |
Deoxidant; improves hot workability |
|
Silicon (Si) |
— |
0.40 |
≤0.15–0.20 |
Kept low to avoid embrittlement phases |
|
Iron (Fe) |
— |
3.00 |
≤1.0 |
Impurity limit |
|
Phosphorus (P) |
— |
0.020 |
— |
— |
|
Sulfur (S) |
— |
0.015 |
— |
— |
|
Lanthanum / Rare Earth |
— |
— (not intentional) |
— |
Differentiator vs. Haynes 188 (which has 0.04–0.08% La) |
3. Room-Temperature Mechanical Property Requirements (Annealed)
AMS 5537 — Sheet / Strip / Plate (Solution Annealed):
|
Property |
Minimum (AMS 5537) |
Typical Mill Range (Annealed) |
|---|---|---|
|
Tensile Strength (Rm) |
≥ 895 MPa (130 ksi) |
960–1040 MPa |
|
Yield Strength (Rp0.2) |
≥ 380 MPa (55 ksi)* |
420–480 MPa |
|
Elongation (A50mm) |
≥ 30 % (heavy plate) / ≥ 35 % (thin sheet per some revisions) |
38–50 % |
|
Hardness |
— |
88–98 HRB (190–230 HB) |
*Some older AMS versions cite ≥ 310 MPa (45 ksi) for bar; sheet/strip typically ≥ 380 MPa.
AMS 5759 — Bar / Forging (Solution Annealed):
|
Property |
Minimum (AMS 5759) |
Typical |
|---|---|---|
|
Rm |
≥ 895 MPa |
960–1040 MPa |
|
Rp0.2 |
≥ 310 MPa (45 ksi) |
400–470 MPa |
|
A50mm |
≥ 30 % |
35–45 % |
4. Elevated-Temperature Tensile — Typical Annealed Values
|
Temp (°C) |
Rm(MPa) |
Rp0.2(MPa) |
Elong. A50(%) |
|---|---|---|---|
|
20 |
960–1040 |
420–480 |
38–50 |
|
205 |
890–955 |
380–440 |
36–46 |
|
540 |
760–830 |
310–370 |
33–42 |
|
760 |
550–610 |
240–290 |
30–38 |
|
870 |
400–450 |
195–235 |
27–35 |
|
980 |
280–330 |
145–180 |
25–32 |
|
1040 |
215–260 |
115–150 |
22–30 |
No ductile-to-brittle transition: elongation > 30 % at –196°C → suitable for LOX/LN₂ valve trim.
Cold-Worked (Spring Temper): UTS can reach 1300–1500 MPa after heavy drawing (used for high-temp spring wire / seal rings).
5. Physical Constants (Annealed, 20°C Unless Noted)
|
Property |
Value |
Note |
|---|---|---|
|
Density |
9.13 g/cm³ (0.330 lb/in³) |
— |
|
Melting Range |
1330–1410°C (2425–2570°F) |
Solidus ~1330°C |
|
Elastic Modulus (E) |
217–221 GPa @20°C; ~158 GPa @1000°C |
— |
|
Mean CTE (20–1000°C) |
16.5 × 10⁻⁶ /K |
— |
|
Thermal Conductivity |
18 W/m·K @100°C; ~28 W/m·K @800°C |
— |
|
Specific Heat (cp) |
~460 J/kg·K @RT |
— |
|
Electrical Resistivity |
~1.25 µΩ·m @20°C |
— |
|
Magnetic Behavior |
Paramagnetic (FCC γ) at all service temps |
— |
6. Heat Treatment / Delivery Condition
Solution Anneal: 1175–1230°C × (time per section thickness) → water quench or high-velocity air blast (thin gauge) → single-phase γ + dissolved carbides.
Mill Delivery Condition: Solution annealed, descaled (pickled or bright annealed), flat-rolled or turned/bored as applicable.
Stress Relief (optional, for dimensional stability only): ≤ 400°C — no precipitation hardening possible.
No aging / precipitation treatment — Haynes 25 is not age-hardenable.
7. Product Forms Normally Supplied to These Specs
|
Form |
Typical Size Range (COCESS capability) |
AMS Ref. |
|---|---|---|
|
Cold-Rolled Sheet / Strip |
0.3–4.0 mm (thicker on request) |
AMS 5537 |
|
Hot-Rolled Plate |
4.0–50 mm+ |
AMS 5537 |
|
Round Bar (Black / Turned / Ground) |
Ø8–Ø300 mm |
AMS 5759 |
|
Spring Wire (Half-Hard / Full-Hard) |
Ø0.2–Ø8.0 mm (coil or straight) |
ASTM F90 / AMS 5797 filler ref. |
|
Forging Billet / Block |
per drawing |
AMS 5759 |
|
Welding Wire |
0.8 / 1.2 / 1.6 / 2.4 mm |
AMS 5797 |
8. Summary Data Takeaways
UNS R30605 = Co–20Cr–10Ni–15W–0.10C, solid-solution strengthened, no La/Ce (vs. Haynes 188).
AMS 5537 (sheet/strip) & AMS 5759 (bar/forging) define chemistry and minima: Rm ≥ 895 MPa, Rp0.2 ≥ 380 MPa (sheet) / ≥310 MPa (bar), A ≥ 30–35%.
Typical annealed Rm 960–1040 MPa @RT; retains Rm ≈ 280–330 MPa @980°C; usable creep to ~760–815°C light load.
Continuous oxidation limit in static air ≈ 1040°C (1900°F); cyclic oxidation inferior to La-doped Haynes 188.
Supplied solution-annealed; spring temper achieved by cold drawing.
