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Nickel Alloy CY-40 vs IN-738LC

Nickel Alloy · grade comparison

Nickel Alloy CY-40 and IN-738LC are both nickel alloy grades. IN-738LC is the stronger of the two: yield strength 945 MPa (137 ksi) against 245 MPa (35.5 ksi) for CY-40, about 3.9 times as much; tensile strength follows at 1,030 MPa (149 ksi) vs 520 MPa (75.4 ksi). In exchange, CY-40 is the more ductile: elongation 38% versus 6% for IN-738LC, and IN-738LC is harder (331 HB vs 145 HB). IN-738LC is lighter (8.11 g/cm³ vs 8.45 g/cm³ for CY-40) and CY-40 conducts heat better (14.8 W/m·K vs 11 W/m·K). On the shop floor, CY-40 machines more easily (poor vs not recommended) and CY-40 welds better (good vs poor).

CY-40Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

IN-738LCChoose it when strength drives the design, or when weight is the constraint.

CY-40 vs IN-738LC: properties

CY-40IN-738LC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
201 GPa29.2 Msi

Shear Modulus

76 GPa11 Msi
78 GPa11.3 Msi

Bulk Modulus

175 GPa25.4 Msi
168 GPa24.4 Msi

Poisson's Ratio

0.31
0.29

Tensile Strength (Ultimate)

520 MPa75.4 ksi
1,030 MPa149 ksi

Yield Strength (0.2% offset)

245 MPa35.5 ksi
945 MPa137 ksi

Elongation at Break

38%
6%

Reduction in Area

40%
8%

Compressive Strength

250 MPa36.3 ksi
1,000 MPa145 ksi

Shear Strength

350 MPa50.8 ksi
670 MPa97.2 ksi

Fatigue Strength (Endurance Limit)

215 MPa31.2 ksi
400 MPa58 ksi

Fracture Toughness (K_IC)

90 MPa·√m81.9 ksi·√in
80 MPa·√m72.8 ksi·√in

Charpy V-Notch Impact (RT)

55 J40.6 ft·lbf
12 J8.9 ft·lbf

Hardness, Brinell

145 HB
331 HB

Hardness, Rockwell B

78 HRB
—

Hardness, Vickers

152 HV
350 HV

Hardness, Rockwell C

—
36 HRC

Physical

Density and transition temperatures.

Density

8.45 g/cm³0.31 lb/in³
8.11 g/cm³0.29 lb/in³

Melting Point (Solidus)

1,354°C2,469 °F
1,230°C2,246 °F

Liquidus Temperature

1,413°C2,575 °F
1,315°C2,399 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

14.8 W/m·K8.6 BTU/hr·ft·°F
11 W/m·K6.4 BTU/hr·ft·°F

Specific Heat Capacity

444 J/kg·K0.11 BTU/lb·°F
430 J/kg·K0.1 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

13.3 µm/m·K7.4 µin/in·°F
11.6 µm/m·K6.4 µin/in·°F

Max Service Temperature (continuous)

1,000°C1,832 °F
980°C1,796 °F

Same in both: Latent Heat of Fusion 290 J/g125 BTU/lb · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

1.7 % IACS
1.3 % IACS

Electrical Resistivity

1.03×10⁻⁶ Ω·m40.6 µΩ·in
1.3×10⁻⁶ Ω·m51.2 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.18 V
-0.15 V

Corrosion Resistance

76 / 100
85 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

28 / 100
12 / 100

Machinability Rating (AISI 1212 = 100 %)

15%
8%

Weldability

60 / 100
15 / 100

Formability (cold)

20 / 100
3 / 100

Castability

58 / 100
72 / 100

Same in both: Brazeability / Solderability 55 / 100 · Polishability 60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

150 MJ/kg64,488 BTU/lb
215 MJ/kg92,433 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
15 kg CO₂/kg

Embodied Water

350 L/kg41.9 gal/lb
300 L/kg35.9 gal/lb

Typical Recycled Content

45%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

62 kN·m/kg
127 kN·m/kg

Specific Stiffness (E / density)

23.7 MN·m/kg
24.8 MN·m/kg

Modulus of Resilience

150 kJ/m³
2,221 kJ/m³

Thermal Diffusivity

3.9 mm²/s
3.2 mm²/s

Thermal Shock Resistance Index

3
5

Strength versus weight

Yield strength against density for every nickel alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

2005001,0006.577.588.59Density (g/cm³)Yield strength (MPa) — log scaleCY-40IN-738LC

Manufacturing and finishing

CapabilityCY-40IN-738LC
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Both take the same 3 finishes: Gold Plating, Plasma Spray, Silver Plating.

CY-40 vs IN-738LC — frequently asked

Is IN-738LC stronger than CY-40?

Yes. IN-738LC has a typical yield strength of 945 MPa (137 ksi) against 245 MPa (35.5 ksi) for CY-40 — about 3.9 times as much. Tensile strength is 1,030 MPa (149 ksi) vs 520 MPa (75.4 ksi).

Which is cheaper, CY-40 or IN-738LC?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, CY-40 or IN-738LC?

CY-40. Its machinability rates poor (28/100) against not recommended (12/100) for IN-738LC; for welding the order is CY-40 first (good, 60/100) then IN-738LC (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in CY-40 and IN-738LC side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.