High temperature alloys
UNS Number | UNS N07090 |
Industry Name | Nimonic 90, Alloy 90, W.Nr.2.4632, NiCr20Co18Ti |
Product Forms | Bars, Plates, Wires |
General Characteristics
Alloy 90 is a precipitation-hardening nickel-chromium-cobalt wrought superalloy. It was designed to deliver superior creep and stress-rupture strength under sustained high-temperature load up to 920°C, addressing the need for turbine hot-section materials that maintain dimensional stability under prolonged thermal cycling.
Its key properties stem from gamma prime (γ’) precipitation strengthened by aluminium and titanium, plus cobalt solid-solution reinforcement. The alloy provides excellent high-temperature tensile strength, thermal fatigue resistance and oxidation resistance, with reliable performance under cyclic thermal stress.
Compared with Nimonic 80A, Alloy 90 contains cobalt and offers markedly better creep strength above 750°C, though it costs more. Unlike Inconel 718, whose strength drops rapidly above 650°C, Alloy 90 retains strength at higher temperatures.
Ni | Fe | Mn | C | Si | S | Cr | Al | Ti | P | Co | B | Zr | Cu |
Balance | 18 | 1 | 2 | 15 | |||||||||
1.5 | 0.4 | 0.13 | 0.8 | 0.015 | 21 | 2 | 3 | 0.02 | 21 | 0.02 | 0.15 | 0.2 |
Industrial Gas Turbine ||Gas turbine hot gas path components |Turbine blading |Exhaust valve components |High-temperature springs
Automotive & Motorsport ||Exhaust valves|Turbocharger hot section parts |High-temperature valve springs
Aerospace Auxiliary & Fastening ||High temperature springs|Spring washers, Belleville springs |Retaining rings, clamping rings|Hot-end fasteners
Technical Standards | Product Form |
ASTM B637 | Bar, Forging, Forged Billet, Ring |
AMS 5829 | Bar, Forging, Ring, Wire, Spring Wire |
AMS 5549 | Plate, Sheet, Strip |
AMS 5582 | Seamless Tube & Pipe |
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 |
Q1: What is the maximum continuous working temperature?
A: Up to 700°C for long-term service; short peak temperature can reach 920°C. Stress relaxation accelerates obviously above 700°C.
Q2: Nimonic 90 vs Nimonic 80A?
A: Nimonic 90 contains cobalt, delivering better creep and stress relaxation resistance at high temperatures. It costs more and has slightly lower ductility than Nimonic 80A.
Q3: Can we age the wire first then coil springs?
A: No. Spring wire must be supplied in solution / spring temper. Spring coiling should be done before final aging, otherwise cracking may occur.
Q4: What melting options can you supply?
A: VIM+ESR for general industrial use; VIM+VAR for aerospace & high-end gas turbine projects.
Q5: Will Alloy 90 lose preload at elevated temperature?
A: It retains preload far better than Inconel 718. But preload will still drop slowly with higher temperature and longer holding time.
Q6: Can you supply to AMS 5829? Does AMS5829 cover spring wire?
A: Yes. AMS 5829 covers bar, forging, ring and spring wire. MTC can be issued to AMS5829.
Q7: Is Nimonic 90 suitable for nuclear service?
A: Not recommended. Cobalt forms radioactive Co 60 under neutron irradiation.
Q8: Will Nimonic90 springs lose its elasticity and stiffness under high temperature?
Alloy 90 offers superior resistance to stress relaxation compared with Inconel 718 and Nimonic 80A. It maintains elasticity well under long-term load, ideal for constant high-temperature preload springs and disc springs.
Q9: What is the temperature limit for Alloy 90?
A: Short peak temperature up to 920°C. Recommended continuous operating temperature ≤700°C. Stress relaxation accelerates significantly above 700°C.