Nickel Alloy Nimonic 105-ST (Solution annealed)
Heat-treated state
EN 2.4634
Softest supplied condition — choose for machining, forming or welding before final ageing.
Values for the ST condition
Other Nimonic 105 tempers and conditions
Nimonic 105 is listed in 4 conditions; see the grade overview at Nimonic 105.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STThis page Solution annealed | Softest supplied condition — choose for machining, forming or welding before final ageing. | 500 | 860 | 35 | 22 HRC | — |
As hot forged / hot rolled bar | Mill product condition for forging stock and re-heat-treatment; properties are non-guaranteed until solution treated and aged. | 650 | 1,000 | 25 | 30 HRC | 1.4 % IACS |
Solution treated + single age | Shortened ageing cycle used for thinner sections and fasteners; slightly lower creep strength than the double-aged cycle. | 770 | 1,100 | 24 | 34 HRC | 1.3 % IACS |
STADefault Solution treated and aged | Standard fully heat-treated condition for turbine discs, blades and hot bolting — maximum creep and tensile strength. | 810 | 1,150 | 22 | 36 HRC | — |
What is Nimonic 105-ST?
Nimonic 105-ST is Nimonic 105 heat treated to ST — softest supplied condition — choose for machining, forming or welding before final ageing. Nimonic 105-ST has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 73% of nickel alloy grades. Elongation at break is 35% and the elastic modulus is 222 GPa (32.2 Msi). Nimonic 105-ST has a density of 8 g/cm³ (0.289 lb/in³), lighter than 85% of nickel alloy grades. It melts at 1,290°C (2,354 °F). STA is the default condition FabDigit quotes; ST is available on request or by drawing note.
Limitations
- High embodied carbon — 16 kg CO₂/kg, worse than 93% of nickel alloy grades
- Difficult to weld — 30/100, worse than 78% of nickel alloy grades
Nimonic 105-ST properties
Typical room-temperature values for Nimonic 105-ST; 12 are specific to this condition. Other listed values are Nimonic 105 reference data and may not represent this condition. Bars are the position among nickel alloy grades.
Physical3
Nimonic 105-ST has a density of 8 g/cm³ (0.289 lb/in³), lighter than 85% of nickel alloy grades. It melts at 1,290°C (2,354 °F).
Mechanical15
Nimonic 105-ST has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 73% of nickel alloy grades. Elongation at break is 35% and the elastic modulus is 222 GPa (32.2 Msi).
Thermal5
Nimonic 105-ST is rated for continuous service to 800°C (1,472 °F). It conducts heat at 10.7 W/m·K (6.18 BTU/hr·ft·°F), worse than 68% of nickel alloy grades. Thermal expansion is 11.8 µm/m·K (6.56 µin/in·°F).
Electrical2
Nimonic 105-ST has an electrical resistivity of 1.3×10⁻⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 77% of nickel alloy grades.
Sustainability4
Producing a kilogram of Nimonic 105-ST takes about 235 MJ of energy and emits 16 kg of CO₂ — more than 94% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
Nimonic 105-ST's machinability is poor (18/100, worse than 61% of nickel alloy grades); weldability poor (30/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Nimonic 105-ST
Is Nimonic 105 easy to machine?
Machine in the solution-treated condition where possible; rigid setups, low speeds with carbide or SiAlON ceramic inserts, heavy positive feed and flood coolant to avoid work hardening and glazing.
Can Nimonic 105 be welded?
High Al+Ti content makes it prone to strain-age and HAZ liquation cracking — weld only in solution-treated condition (GTAW/EB), minimise restraint, and re-solution + re-age afterwards.
Can Nimonic 105 be formed, bent or molded?
Hot work between about 1080 and 1150 °C with light finishing reductions; cold forming is very limited and needs intermediate solution anneals.
What surface finishes work on Nimonic 105?
No anodising; use grinding/polishing, shot peening for fatigue life, and aluminide or MCrAlY diffusion coatings for service above ~900 °C.
Nimonic 105 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Co | 18 – 22 | 20 |
| Cr | 14 – 15.7 | 14.8 |
| Mo | 4.5 – 5.5 | 5 |
| Al | 4.5 – 4.9 | 4.7 |
| Ti | 0.9 – 1.5 | 1.2 |
| C | 0.08 – 0.2 | 0.13 |
| Fe | ≤ 1 | 0.3 |
| Mn | ≤ 1 | 0.1 |
| Si | ≤ 1 | 0.2 |
| Cu | ≤ 0.2 | 0.05 |
| B | 0 – 0.01 | 0.01 |
| Zr | ≤ 0.15 | 0.1 |
| S | ≤ 0.02 | — |
| Nibalance, typically ~53% | balance | — |
Nimonic 105-ST — frequently asked
What is Nimonic 105-ST used for?
Nimonic 105-ST is typically used for turbine discs, turbine blades and high-temperature fasteners. In short: creep strength to 950 °C; forged rotating-part superalloy; very low machinability rating.
What is the yield strength of Nimonic 105-ST?
Nimonic 105-ST has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 73% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is Nimonic 105-ST easy to machine?
Not especially — machinability is rated poor (18/100, worse than 61% of nickel alloy grades). Machine in the solution-treated condition where possible; rigid setups, low speeds with carbide or SiAlON ceramic inserts, heavy positive feed and flood coolant to avoid work hardening and glazing.
Can Nimonic 105-ST be welded?
Not readily — weldability is rated poor (30/100). High Al+Ti content makes it prone to strain-age and HAZ liquation cracking — weld only in solution-treated condition (GTAW/EB), minimise restraint, and re-solution + re-age afterwards.
What surface finishes work on Nimonic 105-ST?
No anodising; use grinding/polishing, shot peening for fatigue life, and aluminide or MCrAlY diffusion coatings for service above ~900 °C.
Can Nimonic 105-ST be formed, bent or molded?
Hot work between about 1080 and 1150 °C with light finishing reductions; cold forming is very limited and needs intermediate solution anneals.
What is the maximum service temperature of Nimonic 105-ST?
Nimonic 105-ST is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Nimonic 105-STA and Nimonic 105-ST?
STA is the default condition — standard fully heat-treated condition for turbine discs, blades and hot bolting — maximum creep and tensile strength. ST: softest supplied condition — choose for machining, forming or welding before final ageing. Yield strength is 810 MPa in STA versus 500 MPa in ST.
Sources
- Nimonic alloy 105 technical data — Special Metals Corporation (Henry Wiggin) (2004)
- BS HR3 / DIN 17742 material 2.4634 (NiCo20Cr15MoAlTi) — BSI / DIN (1999)
- ASM Handbook Vol. 1: Properties and Selection — Superalloys — ASM International (1990)
- Superalloys: A Technical Guide, 2nd ed. — ASM International (2002)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.