Alloy 901, 2.4662, UNS N09901, Nimonic® alloy 901 - NICKEL ALLOY

Alloy 901, 2.4662, UNS N09901, Nimonic® alloy 901 - nickel alloy according to AMS 5660, 5661, 5830

Alloy 901, N09901, Nimonic alloy 901 – description

Alloy 901 (UNS N09901) is an precipitation-hardenable Ni-Fe-Cr superalloy with molybdenum and titanium as alloying additions. The alloying route may include vacuum induction melting, vacuum arc remelting and electroslag remelting. The alloy is typically used up to 600°C.

Applications

Used for gas turbine engine discs, shafts, rings, casings and seals.

Physical and Tensile Properties

Room temperature physical properties:

• Density: 8.14 g/cm³
• Liquidus Temperature: 1345 °C
• Solidus Temperature: 1280 °C
• Specific Heat Capacity: 431 J/kg⋅K
• Electrical Resistivity: 1.12 μΩ·m

High-Temperature Coefficient of Thermal Expansion, from 20°C to:

• 100°C: 13.5 μm/m⋅K
• 200°C: 14.2 μm/m⋅K
• 300°C: 14.3 μm/m⋅K
• 400°C: 14.5 μm/m⋅K
• 500°C: 14.8 μm/m⋅K
• 600°C: 15.0 μm/m⋅K
• 700°C: 15.3 μm/m⋅K
• 800°C: 16.1 μm/m⋅K
• 900°C: 17.5 μm/m⋅K
• 1000°C: 19.9 μm/m⋅K

Thermal Conductivity:

• 40°C: 13.4 W/m · K
• 167°C: 14.3 W/m · K
• 246°C: 15.4 W/m · K
• 360°C: 16.3 W/m · K
• 457°C: 17.6 W/m · K
• 540°C: 18.3 W/m · K
• 650°C: 19.3 W/m · K
• 760°C: 20.5 W/m · K

Young's Modulus:

• 20°C: 201 GPa
• 100°C: 198 GPa
• 200°C: 192 GPa
• 300°C: 185 GPa
• 400°C: 179 GPa
• 500°C: 172 GPa
• 600°C: 166 GPa
• 700°C: 159 GPa
• 800°C: 150 GPa
• 900°C: 138 GPa
• 1000°C: 126 GPa

Thermal Stability - room temperature impact value of Nimonic alloy 901 depending on the soaking temperature and time:

• 550°C:
  • 30 h: 58 J
  • 100 h: 47 J
  • 300 h: 47 J
  • 1 000 h: 41 J
  • 3 000 h: 42 J
  • 10 000 h: 41 J
• 600°C: J
  • 30 h: 44 J
  • 100 h: 50 J
  • 300 h: 57 J
  • 1 000 h: 38 J
  • 3 000 h: 47 J
  • 10 000 h: 15 J
• 650°C: J
  • 30 h: 49 J
  • 100 h: 45 J
  • 300 h: 37 J
  • 1 000 h: 14 J
  • 3 000 h: 12 J
  • 10 000 h: 12 J
• 700°C: J
  • 30 h: 41 J
  • 100 h: 32 J
  • 300 h: 18 J
  • 1 000 h: 12 J
  • 10 000 h: 5 J
• 750°C: J
  • 30 h: 50 J
  • 100 h: 27 J
  • 300 h: 14 J
  • 1 000 h: 5 J
  • 3 000 h: 5 J
  • 10 000 h: 5 J

Thermal Stability - high-temperature impact value of Nimonic alloy 901 depending on the soaking temperature and time:

• 550°C:
  • 30 h: 49 J
  • 100 h: 45 J
  • 300 h: 44 J
  • 1 000 h: 73 J
  • 3 000 h: 47 J
  • 10 000 h: 52 J
• 600°C: J
  • 30 h: 50 J
  • 30 h: 41 J
  • 100 h: 41 J
  • 300 h: 45 J
  • 1 000 h: 49 J
  • 3 000 h: 41 J
  • 10 000 h: 22 J
• 650°C: J
  • 30 h: 56 J
  • 30 h: 37 J
  • 100 h: 45 J
  • 300 h: 34 J
  • 1 000 h: 26 J
  • 3 000 h: 20 J
  • 10 000 h: 22 J
• 700°C: J
  • 30 h: 42 J
  • 30 h: 46 J
  • 100 h: 34 J
  • 300 h: 41 J
  • 1 000 h: 28 J
  • 3 000 h: - J
  • 10 000 h: 12 J
• 750°C: J
  • 0 h: 50 J
  • 30 h: 27 J
  • 100 h: 42 J
  • 300 h: 31 J
  • 1 000 h: 24 J
  • 3 000 h: 15 J
  • 10 000 h: 18 J

Stress Rupture Strength of Pyromet alloy 901:

• 540°C:
  • 100 h: 827 MPa
  • 1 000 h: 689 MPa
• 650°C: MPa
  • 100 h: 621 MPa
  • 1 000 h: 517 MPa
• 730°C: MPa
  • 100 h: 352 MPa
  • 1 000 h: 228 MPa
• 815°C: MPa
  • 100 h: 155 MPa
  • 1 000 h: 76 MPa

Creep Strength of Pyromet alloy 901 - stress to produce 0,1% creep in 100 hours at:

• 540°C: 724 MPa
• 650°C: 503 MPa
• 760°C: 186 MPa

High-Temperature Tensile Properties:

• 20°C:
  • Yield strength: 895 MPa
  • Tensile strength: 1205 MPa
  • Elongation: 14 %
• 540°C:
  • Yield strength: 780 MPa
  • Tensile strength: 1030 MPa
  • Elongation: 25 %
• 760°C:
  • Yield strength: 635 MPa
  • Tensile strength: 725 MPa
  • Elongation: 19 %

Corrosion Resistance

Good corrosion resistance to jet engine atmospheres.

Heat Treatment, Working and Machining

Standard recommended working and heat treatment parameters:

• Forging: 1120-1010 °C
• Light forging: >870 °C
• Solution-treatment: 1090°C; 3 h; water quench
• Stabilizing anneal: 775°C; 2 h; air cool
• Age hardening: 705-720°C; 24 h; air cool

Thermal-Mechanical Processing is done to produce a fine-grain structure that enhances fatigue strength. This is accomplished by using the η (Ni₃Ti) phase, which is introduced in Widmanstätten form at the beginning of processing by a heat treatment at 900°C for 8 h. Forging is then conducted at 955°C, which is below the η solvus; the forging deformation is completed below the recrystallization temperature. A fine-grain structure is generated by a subsequent recrystallization treatment below the η solvus. The needlelike η phase will become spherical during forging and will restrict grain growth. Aging is then conducted according to standard procedures

Machinability: decent machinability in all heat-treated conditions, best machinability when over-aged. A cost-effective approach is machining after partial aging, i.e., solution annealing followed by air cooling. Drilling and tapping may require the alloy to be at its lowest hardness, achieved through solution annealing and rapid water quenching.

Weldability

The alloy is difficult to weld. The presence of titanium may increase the risk of hot cracking. Weld in a solution-annealed condition. Cold-worked parts should be solution-annealed before welding. After welding, the part should be re-solutioned, after which standard stabilizing annealing and aging can be performed.

We deliver this steel alloy as:

• Rod, bar, wire, forging according to BR HR 55, SAE AMS 5660, SAE AMS 5661, AECMA PrEN2176, AECMA PrEN2177, ISO 9723, ISO 9725
• Other according to AECMA PrEN2178