Nickel Alloy IN-738LC
UNS N07738
IN-738LC (UNS N07738) is a low-carbon cast Ni-Cr-Co superalloy strengthened by a high γ′ volume fraction (over 40 %), and is one of the most widely used industrial gas turbine blade alloys for its hot corrosion resistance.
Reference datasheet — IN-738LC 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 FHT condition
IN-738LC tempers and conditions
IN-738LC is supplied in 4 conditions, soft to hard. FHT is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Raw investment casting before solution/age; used only as an intermediate state or for non-critical hardware. | 760 | 830 | 4 | 32 HRC | 1.3 % IACS |
Directionally solidified casting, solution + aged | Columnar-grain version for higher thermal-fatigue and creep capability along the blade stacking axis. | 880 | 1,000 | 10 | 35 HRC | 1.3 % IACS |
FHTDefault Full heat treatment: 1120 °C/2 h/AC + 843 °C/24 h/AC | Standard supplied condition for conventionally cast turbine blades and vanes — best balance of γ′ strengthening and creep life. | 945 | 1,030 | 6 | 36 HRC | 1.3 % IACS |
hot isostatic pressed (~1200 °C / 100–170 MPa / 4 h) then solution + age | Choose when casting microporosity must be closed for maximum LCF/creep life on high-duty rotating blades. | 960 | 1,090 | 8 | 36 HRC | 1.3 % IACS |
Supply forms, finishes and certifications
Ways IN-738LC is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
LPBF-AB | LPBF as-built | Printing process |
LPBF-HIP+HT | LPBF + HIP + solution/age | Printing process |
What is IN-738LC?
IN-738LC (UNS N07738) is a low-carbon cast Ni-Cr-Co superalloy strengthened by a high γ′ volume fraction (over 40 %), and is one of the most widely used industrial gas turbine blade alloys for its hot corrosion resistance. It is supplied only as investment castings — equiaxed, directionally solidified, HIP+heat treated, or laser powder bed fusion builds — with typical properties of 945 MPa yield, 1030 MPa tensile, 6 % elongation and 36 HRC up to about 980 °C. Limits are low ductility, machinability score 12, high weld-crack sensitivity and long casting lead times. IN-939 is the nearest cast alternative when higher chromium and hot corrosion resistance are prioritised over strength. IN-738LC has a density of 8.11 g/cm³ (0.293 lb/in³), lighter than 77% of nickel alloy grades. It melts at 1,230°C (2,246 °F). IN-738LC has a yield strength of 945 MPa (137 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 94% of nickel alloy grades. Elongation at break is 6% and the elastic modulus is 201 GPa (29.2 Msi).
What is IN-738LC used for?
- industrial gas turbine blades
- vanes
- hot corrosion-resistant hot-section parts
Advantages
- High strength — 945 MPa (137 ksi), better than 94% of nickel alloy grades
Limitations
- Limited formability — 3/100, worse than 97% of nickel alloy grades
- Limited ductility — 6%, worse than 90% of nickel alloy grades
- Difficult to weld — 15/100, worse than 87% of nickel alloy grades
- High embodied carbon — 15 kg CO₂/kg, worse than 87% of nickel alloy grades
- Hard to polish — 60/100, worse than 84% of nickel alloy grades
IN-738LC properties
Typical room-temperature values for IN-738LC-FHT; bars are the position among nickel alloy grades.
Physical3
IN-738LC has a density of 8.11 g/cm³ (0.293 lb/in³), lighter than 77% of nickel alloy grades. It melts at 1,230°C (2,246 °F).
Mechanical16
IN-738LC has a yield strength of 945 MPa (137 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 94% of nickel alloy grades. Elongation at break is 6% and the elastic modulus is 201 GPa (29.2 Msi).
Thermal6
IN-738LC is rated for continuous service to 980°C (1,796 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), worse than 60% of nickel alloy grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
IN-738LC conducts electricity at 1.3 % IACS, worse than 89% of nickel alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 74% of nickel alloy grades.
Sustainability4
Producing a kilogram of IN-738LC takes about 215 MJ of energy and emits 15 kg of CO₂ — more than 84% of nickel alloy grades. Typical recycled content is 30%.
Manufacturability8
IN-738LC's machinability is not recommended (12/100, worse than 86% of nickel alloy grades); weldability poor (15/100); formability not recommended (3/100).
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-738LC is highlighted; hover a dot for its name, or open the interactive family chart.
Working with IN-738LC
Is IN-738LC easy to machine?
Very difficult: rigid setups, ceramic or coated-carbide tools, low speeds with high feed, flood coolant; grinding, EDM and ECM are standard for cooling holes and root forms.
Can IN-738LC be welded?
Highly crack-sensitive (γ′ >40 %): weld in solutioned/over-aged condition, use preheat or hot-box GTAW/laser cladding with ductile Ni fillers, followed by full solution + age; wide-gap brazing is the preferred repair route.
Can IN-738LC be formed, bent or molded?
Investment casting only (equiaxed, DS or LPBF); no cold forming — control shell temperature and gating to avoid hot tearing and shrinkage porosity, HIP to close residual porosity.
IN-738LC 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 |
|---|---|---|
| Clow-carbon variant of IN-738 | 0.09 – 0.13 | 0.11 |
| Crhot-corrosion resistance | 15.7 – 16.3 | 16 |
| Co | 8 – 9 | 8.5 |
| Mo | 1.5 – 2 | 1.75 |
| W | 2.4 – 2.8 | 2.6 |
| Ta | 1.5 – 2 | 1.75 |
| Nb | 0.6 – 1.1 | 0.9 |
| Alγ′ former | 3.2 – 3.7 | 3.4 |
| Tiγ′ former | 3.2 – 3.7 | 3.4 |
| B | 0.01 | 0.01 |
| Zr | 0.03 – 0.08 | 0.05 |
| Fe | ≤ 0.5 | |
| Si | ≤ 0.3 | |
| Mn | ≤ 0.2 | |
| S | ≤ 0.02 | |
| Nibalance, ~61 % | balance |
What surface finishes work on IN-738LC?
Grit blast and chemical clean, then aluminide diffusion or MCrAlY overlay coating plus optional YSZ thermal-barrier coat; polish or vibro-finish airfoils before coating.
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
Equivalent designations
Standards and trade names that resolve to Nickel Alloy IN-738LC in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N07738
How much does IN-738LC cost?
IN-738LC 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-738LC — frequently asked
What is IN-738LC used for?
IN-738LC is typically used for industrial gas turbine blades, vanes and hot corrosion-resistant hot-section parts. In short: benchmark IGT blade alloy; strong hot corrosion resistance; castings only, weld-sensitive.
What is the yield strength of IN-738LC?
IN-738LC has a typical yield strength of 945 MPa (137 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 94% of nickel alloy grades. Strength varies by condition: see the 4 listed tempers.
Is IN-738LC easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 86% of nickel alloy grades). Very difficult: rigid setups, ceramic or coated-carbide tools, low speeds with high feed, flood coolant; grinding, EDM and ECM are standard for cooling holes and root forms.
Can IN-738LC be welded?
Not readily — weldability is rated poor (15/100). Highly crack-sensitive (γ′ >40 %): weld in solutioned/over-aged condition, use preheat or hot-box GTAW/laser cladding with ductile Ni fillers, followed by full solution + age; wide-gap brazing is the preferred repair route.
What surface finishes work on IN-738LC?
Grit blast and chemical clean, then aluminide diffusion or MCrAlY overlay coating plus optional YSZ thermal-barrier coat; polish or vibro-finish airfoils before coating.
Can IN-738LC be formed, bent or molded?
Investment casting only (equiaxed, DS or LPBF); no cold forming — control shell temperature and gating to avoid hot tearing and shrinkage porosity, HIP to close residual porosity.
What is the maximum service temperature of IN-738LC?
IN-738LC is rated for continuous use to about 980°C (1,796 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between IN-738LC-FHT and IN-738LC-AC?
FHT is the default condition — standard supplied condition for conventionally cast turbine blades and vanes — best balance of γ′ strengthening and creep life. AC: raw investment casting before solution/age; used only as an intermediate state or for non-critical hardware. Yield strength is 945 MPa in FHT versus 760 MPa in AC.
How much does IN-738LC cost?
IN-738LC 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
- IN-738 Alloy Technical Data (Inco/Special Metals) — International Nickel Co. / Special Metals (1981)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Superalloys II — High-Temperature Materials for Aerospace and Industrial Power — Wiley (1987)
- UNS N07738 alloy designation (Metals & Alloys in the Unified Numbering System) — SAE/ASTM (2017)
- Cast Ni-base superalloy property compilations (thermophysical and mechanical data) — NIMS / open literature (2020)
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.