Cobalt alloys
UNS Number | UNS R30605 |
Industry Name | Haynes 25, W.Nr. 2.4964 |
Product Forms | Bars, Plates, Wires |
General Characteristics
Alloy L605, also known as Haynes 25, is a solution strengthened cobalt-chromium-tungsten-nickel superalloy. It was developed to overcome the insufficient high-temperature creep, oxidation and sulfidation resistance of early nickel-base superalloys used in gas turbine hot sections. Many early nickel alloys lost strength rapidly above 760°C and suffered severe scaling and corrosion in sulfur-containing hot flue gas.
It is designed for continuous high-temperature service under combined thermal load, oxidation, sulfidation, friction and mechanical stress. Its key strengths include excellent high-temperature tensile and creep strength, outstanding oxidation resistance up to 1093°C, good wear and galling resistance, sulfidation resistance, non-magnetic property and biocompatibility. Its strength can be greatly improved by cold working.
Element | Content |
Cobalt (Co) | Balance |
Chromium (Cr) | 19.0 – 21.0 |
Tungsten (W) | 14.0 – 16.0 |
Nickel (Ni) | 9.0 – 11.0 |
Manganese (Mn) | 1.0 – 2.0 |
Carbon (C) | 0.05 – 0.15 |
Silicon (Si) | ≤ 0.40 |
Iron (Fe) | ≤ 3.0 |
Phosphorus (P) | ≤ 0.04 |
Sulfur (S) | ≤ 0.03 |
Medical Industry||Vascular stents|Heart valve frames|Surgical fixation wires|Orthopedic implant components
Chemical & Petrochemical Industry||High-temperature furnace liners|Valve internal wear-resistant parts|Heat exchanger components for corrosive hot gas|Sulfidation-resistant process piping parts
Industrial High-temperature Engineering||High-temperature ball bearings and bearing races|Furnace fixture components|Heat treatment tray parts|Wear-resistant high-temperature disc springs
Marine||Marine gas turbine hot-section parts|Corrosion-resistant exhaust components
Technical Standards | Product Form |
AMS 5537 | Sheet, Strip |
AMS 5759 | Bar, Forging, Wire |
AMS 5796 | Welding Wire |
ASTM F90 | Bar, Strip, Sheet (Medical Implants) |
Product form | Size range (mm) |
Forged bar | Dia.70-500 |
Rolled bar | Dia.2.0-70 |
Flat bar | T4-50*W60-300 |
Wire | Dia.0.25-18.0 |
Plate | 1-25 * ≤1200 * ≤1200 |
Seamless tube | OD 6.0-200 * 0.6-20 |
Q1: The difference between Alloy L605 and Waspaloy?
A: Waspaloy is a nickel-base superalloy optimized for turbine discs with higher creep resistance for rotating components. L605 is cobalt-based, has superior oxidation/sulfidation resistance and better fabricability into sheet and strip, making it more suitable for static combustor liners and high-temperature springs.
Q2: Alloy L605 VS Inconel 718?
A: Inconel 718 loses strength quickly above 650°C, while L605 retains mechanical properties at much higher temperatures, though L605 costs more and has poorer machinability.
Q3: What is its typical working temperature?
A: Continuous service up to 980°C, intermittent peak temperature up to 1093°C. Creep performance will degrade under long-time exposure above 980°C.
Q4: Is L605 precipitation hardenable?
A: No. It is solid-solution strengthened. Its strength improvement mainly comes from cold working. Solution annealing is used to restore ductility and relieve stress.
Q5: Is Alloy L605 non-magnetic?
A: Yes, it remains non-magnetic in all heat treatment and cold-worked conditions.
Q6: Alloy L605 coefficient of thermal expansion?
θ/°C | 20-200 | 20-400 | 20-500 | 20-600 | 20-700 | 20-800 | 20-900 | 20-1000 | 20-1100 |
α | 12.9 | 13.8 | 14.2 | 14.6 | 15.1 | 15.7 | 16.3 | 17 | 17.8 |
Q7: Alloy L605 modulus of elasticity?
θ/°C | 25 | 200 | 425 | 540 | 650 | 870 | 980 |
E/GPa | 231 | 217 | 199 | 196 | 181 | 162 | 148 |
Q8: Alloy L605 shear modulus?
θ/°C | 25 | 200 | 425 | 650 | 870 |
E/GPa | 89 | 83 | 76 | 68 | 61 |
Q9: Alloy L605 oxidation depth when performing oxidation resistance test in still air?
Oxidation Condition | Oxidation Depth/(mm/single side) | ||||
θ/°C | t/h | Oxidation Scale | Intergranular Oxidation | Depletion | Total Depth |
850 | 500 | 0.005 | 0.008 | 0.008 | 0.013 |
950 | 500 | 0.01 | 0.02 | 0.038 | 0.048 |
1000 | 500 | 0.025 | 0.025 | 0.056 | 0.081 |
1000 | 1000 | 0.018 | 0.091 | 0.091 | 0.109 |
1000 | 5000 | 0.051 | 0.102 | 0.102 | 0.153 |
1000 | 10000 | 0.051 | 0.102 | 0.102 | 0.203 |
1150 | 500 | 0.041 | 0.038 | 0.076 | 0.117 |
1150 | 3000 | / | / | / | 4.445 |
*Haynes is a trademark refers to high performance alloy belongs to Haynes International INC.
*Stellite is a trademark refers to cobalt based alloy belongs to Kennametal INC.