Nickel Alloy IN-939
IN-939 is a cast Ni-Co-Cr superalloy with high chromium for hot corrosion resistance, used for industrial gas turbine hot-section parts.
Reference datasheet — IN-939 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the HT condition
IN-939 tempers and conditions
IN-939 is supplied in 6 conditions, soft to hard. HT is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Foundry delivery state for non-critical or to-be-heat-treated parts; lowest strength and coarse as-cast γ′. | 620 | 870 | 4 | 31 HRC | 1.4 % IACS |
Two-step treatment | Simplified/short-cycle heat treatment used for some vanes and repair parts; slightly lower creep life than the four-step cycle. | 760 | 1,050 | 5 | 36 HRC | 1.4 % IACS |
Directionally solidified casting, fully heat treated | Columnar-grain version for higher thermal-fatigue and creep life in long IGT blades; properties quoted along the growth direction. | 760 | 1,060 | 9 | 36 HRC | 1.4 % IACS |
HTDefault Full four-step heat treatment | Standard commercial condition for IGT blades and vanes: optimum γ′ size distribution plus grain-boundary carbide morphology for creep and hot-corrosion life. | 780 | 1,100 | 5.5 | 37 HRC | — |
Hot isostatic pressed then fully heat treated | Choose when internal casting porosity must be closed: best ductility, LCF and creep-rupture scatter reduction for critical rotating blades. | 800 | 1,130 | 8 | 37 HRC | 1.4 % IACS |
Laser powder-bed fusion, hot isostatic pressed and fully heat treated | Additive route for repair inserts and complex cooled components; fine grains give higher room-temperature strength but lower long-term creep than cast/DS material. | 850 | 1,150 | 9 | 38 HRC | 1.4 % IACS |
What is IN-939?
IN-939 is a cast Ni-Co-Cr superalloy with high chromium for hot corrosion resistance, used for industrial gas turbine hot-section parts. It is available as vacuum investment castings in as-cast, heat-treated, HIP+HT, directionally solidified and LPBF+HIP+HT conditions, with typical properties of 780 MPa yield, 1100 MPa tensile, 5.5 % elongation, 37 HRC and a corrosion resistance score of 80. Limits are a 850 °C service ceiling, machinability score 12, weld-crack sensitivity from about 5.6 % Al+Ti, and low ductility. IN-738LC is the nearest alternative when higher temperature capability is required. IN-939 has a density of 8.16 g/cm³ (0.295 lb/in³), lighter than 73% of nickel alloy grades. It melts at 1,290°C (2,354 °F). IN-939 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 83% of nickel alloy grades. Elongation at break is 5.5% and the elastic modulus is 205 GPa (29.7 Msi).
What is IN-939 used for?
- industrial gas turbine blades
- nozzle guide vanes
- hot corrosion-resistant castings
Advantages
- High strength — 780 MPa (113 ksi), better than 83% of nickel alloy grades
Limitations
- Limited ductility — 5.5%, worse than 91% of nickel alloy grades
- Limited formability — 5/100, worse than 91% of nickel alloy grades
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
- Difficult to weld — 25/100, worse than 82% of nickel alloy grades
- Low fracture toughness — 75 MPa·√m (68.3 ksi·√in), worse than 81% of nickel alloy grades
IN-939 properties
Typical room-temperature values for IN-939-HT; bars are the position among nickel alloy grades.
Physical3
IN-939 has a density of 8.16 g/cm³ (0.295 lb/in³), lighter than 73% of nickel alloy grades. It melts at 1,290°C (2,354 °F).
Mechanical13
IN-939 has a yield strength of 780 MPa (113 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 83% of nickel alloy grades. Elongation at break is 5.5% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
IN-939 is rated for continuous service to 850°C (1,562 °F). It conducts heat at 10.5 W/m·K (6.07 BTU/hr·ft·°F), worse than 73% of nickel alloy grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical2
IN-939 has an electrical resistivity of 1.25×10⁻⁶ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 61% of nickel alloy grades.
Sustainability4
Producing a kilogram of IN-939 takes about 215 MJ of energy and emits 14.5 kg of CO₂ — more than 84% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
IN-939's machinability is not recommended (12/100, worse than 86% of nickel alloy grades); weldability poor (25/100); formability not recommended (5/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the nickel alloy family
Yield strength against density for every nickel alloy grade FabDigit runs. IN-939 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with IN-939
Is IN-939 easy to machine?
Very difficult after aging — use rigid setups, ceramic or SiAlON inserts for roughing and coated carbide with heavy through-coolant for finishing at low speed/high feed; grinding, ECM and EDM are common for blade features.
Can IN-939 be welded?
Weld-crack sensitive (Al+Ti ≈ 5.6 %); repair by GTAW/laser with low-heat input in the solution-treated state, preheat, ductile Ni filler or wide-gap braze, followed by full re-heat-treatment and HIP where possible.
Can IN-939 be formed, bent or molded?
Vacuum investment casting (equiaxed or directionally solidified) with ceramic cores; no cold forming — grain-size, shrinkage porosity and shell reaction control are the key process levers.
IN-939 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 |
|---|---|---|
| C | 0.13 – 0.17 | 0.15 |
| Crhigh Cr for hot-corrosion resistance | 22 – 22.8 | 22.5 |
| Co | 18.5 – 19.5 | 19 |
| W | 1.8 – 2.2 | 2 |
| Nb | 0.9 – 1.1 | 1 |
| Ta | 1.3 – 1.5 | 1.4 |
| Tiγ′ former | 3.6 – 3.8 | 3.7 |
| Alγ′ former | 1.8 – 2 | 1.9 |
| Zrgrain-boundary strengthener | 0.08 – 0.12 | 0.1 |
| B | 0.01 – 0.02 | 0.01 |
| Feresidual | ≤ 0.5 | |
| Siresidual | ≤ 0.2 | |
| Mnresidual | ≤ 0.2 | |
| Sresidual | ≤ 0.02 | |
| Nibalance, ~48 % | balance |
What surface finishes work on IN-939?
Chemical/abrasive-flow deburring, shot peening for fatigue, then aluminide diffusion or MCrAlY / TBC coatings for hot-corrosion and oxidation protection; anodizing not applicable.
Surface treatments FabDigit runs on nickel alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
Thermal Spray
How much does IN-939 cost?
IN-939 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
IN-939 — frequently asked
What is IN-939 used for?
IN-939 is typically used for industrial gas turbine blades, nozzle guide vanes and hot corrosion-resistant castings. In short: high-chromium cast superalloy; hot corrosion service castings; requires post-weld heat treatment.
What is the yield strength of IN-939?
IN-939 has a typical yield strength of 780 MPa (113 ksi) and a tensile strength of 1,100 MPa (160 ksi) — stronger than 83% of nickel alloy grades. Strength varies by condition: see the 6 listed tempers.
Is IN-939 easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 86% of nickel alloy grades). Very difficult after aging — use rigid setups, ceramic or SiAlON inserts for roughing and coated carbide with heavy through-coolant for finishing at low speed/high feed; grinding, ECM and EDM are common for blade features.
Can IN-939 be welded?
Not readily — weldability is rated poor (25/100). Weld-crack sensitive (Al+Ti ≈ 5.6 %); repair by GTAW/laser with low-heat input in the solution-treated state, preheat, ductile Ni filler or wide-gap braze, followed by full re-heat-treatment and HIP where possible.
What surface finishes work on IN-939?
Chemical/abrasive-flow deburring, shot peening for fatigue, then aluminide diffusion or MCrAlY / TBC coatings for hot-corrosion and oxidation protection; anodizing not applicable.
Can IN-939 be formed, bent or molded?
Vacuum investment casting (equiaxed or directionally solidified) with ceramic cores; no cold forming — grain-size, shrinkage porosity and shell reaction control are the key process levers.
What is the maximum service temperature of IN-939?
IN-939 is rated for continuous use to about 850°C (1,562 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between IN-939-HT and IN-939-F?
HT is the default condition — standard commercial condition for IGT blades and vanes: optimum γ′ size distribution plus grain-boundary carbide morphology for creep and hot-corrosion life. F: foundry delivery state for non-critical or to-be-heat-treated parts; lowest strength and coarse as-cast γ′. Yield strength is 780 MPa in HT versus 620 MPa in F.
How much does IN-939 cost?
IN-939 is a high-cost nickel alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Superalloys II — High-Temperature Materials for Aerospace and Industrial Power — Wiley (1987)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- IN-939 cast nickel-base superalloy data — Special Metals / Inco Alloys (2004)
- High-temperature alloy thermophysical and mechanical property compilations — NIMS / Cindas (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.