Nimonic 90

Nimonic90 aging hardening nickel-based wrought superalloy
Features and applications overview:
Nimonic90 is age hardenable nickel-based wrought superalloy containig a higher amount of cobalt and a variety of strengthening elements. The alloy has rather high tensile strength and creep resistance in the temperature of 815~870°C, good resistance to oxidation and corrosion, high fatigue strength as well as good formability and weldability under the alternately repeated action of hot and cold. The alloy is used for turbine engine's turbine discs, blades, high-temperature fasteners, clamps, seals and elastic elements.
Nimonic 90's similar grade:
GH90(China)
Chemical composition, %:
Nickel........................................balance
Chromium..................................18.0-21.0
Iron.............................................1.5 max
Zirconium...................................0.15 max
Boron..........................................0.02 max
Cobalt.........................................15.0-21.0
Carbon........................................0.13 max
Manganese..................................0.4 max
Silicon.........................................0.08 max
Sulfur...........................................0.015 max
Phosphorus...................................0.02 max
Copper..........................................0.2 max
Aluminium....................................1.0-2.0
Titanium........................................2.0-3.0
Physical properties:
Density, g/cm3 ................................8.2
Melting Range, °C.........................1400
Thermal conductivity,
λ/(W/m•°C), at 100°C ..................21.76
Elastic modulus, GPa.....................225
Coefficient of linear expansion,
a/10-6°C-1, at 20-100°C.............12.71

Mechanical properties: (the minimum value detected at room temperature)
Tensile strength, σb/MPa............820
Yield strength,σp0.2/MPa.......590
Elongation,σ5 /%...........................8
The way of heat treatment is solution treatment
The metallurgical structure of Nimonic90
The alloy's main strengthening phase is γ'-Ni3(Ti、Al), precipitated out in the form of different sizes of square granules. This shape of γ'phase can be seen on the grain boundary, on which carbides precipitate in the form of discontinuous chain.
The process performance and requirements of Nimonic90:
1, The alloy prone to internal crack in the forging. The hammer blow is allowed, but low-temperature chamfering is not allowed. The temperature is no higher than 700°C upon ingots installed in furnace. The final heating temperature is 1150°C±10°C, open forging temperature not lower than 1060°C, and final forging temperature not less than 950°C.
2, The average size of the grain size of the alloy is closely related to the forging deformation degree and the final forging temperature.
3, Inert gas protects tungsten arc welding and flash butt welding when this alloy is in solid solution state.