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Nickel Alloy Alloy 333 vs Inconel 725

Nickel Alloy · grade comparison

Nickel Alloy Alloy 333 and Inconel 725 are both nickel alloy grades. Inconel 725 is the stronger of the two: yield strength 890 MPa (129 ksi) against 310 MPa (45 ksi) for Alloy 333, about 187% more; tensile strength follows at 1,240 MPa (180 ksi) vs 690 MPa (100 ksi). In exchange, Alloy 333 is the more ductile: elongation 50% versus 25% for Inconel 725, and Inconel 725 is harder (330 HB vs 190 HB). Alloy 333 runs hotter in service (1,100°C vs 650°C continuous). On the shop floor, Alloy 333 machines more easily (poor vs not recommended) and Alloy 333 welds better (very good vs good).

Alloy 333Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

Inconel 725Choose it when strength drives the design.

Alloy 333 vs Inconel 725: properties

Alloy 333Inconel 725

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

203 GPa29.4 Msi
204 GPa29.6 Msi

Shear Modulus

78 GPa11.3 Msi
79 GPa11.5 Msi

Bulk Modulus

165 GPa23.9 Msi
162 GPa23.5 Msi

Poisson's Ratio

0.31
0.29

Tensile Strength (Ultimate)

690 MPa100 ksi
1,240 MPa180 ksi

Yield Strength (0.2% offset)

310 MPa45 ksi
890 MPa129 ksi

Elongation at Break

50%
25%

Reduction in Area

55%
42%

Compressive Strength

320 MPa46.4 ksi
920 MPa133 ksi

Shear Strength

450 MPa65.3 ksi
740 MPa107 ksi

Fatigue Strength (Endurance Limit)

290 MPa42.1 ksi
480 MPa69.6 ksi

Charpy V-Notch Impact (RT)

150 J111 ft·lbf
60 J44.3 ft·lbf

Hardness, Brinell

190 HB
330 HB

Hardness, Rockwell B

90 HRB
—

Hardness, Rockwell C

10 HRC
35 HRC

Hardness, Vickers

200 HV
345 HV

Same in both: Fracture Toughness (K_IC) 110 MPa·√m100 ksi·√in

Physical

Density and transition temperatures.

Density

8.14 g/cm³0.29 lb/in³
8.31 g/cm³0.3 lb/in³

Melting Point (Solidus)

1,330°C2,426 °F
1,271°C2,320 °F

Liquidus Temperature

1,400°C2,552 °F
1,343°C2,449 °F

Thermal

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

Thermal Conductivity

11 W/m·K6.4 BTU/hr·ft·°F
10.8 W/m·K6.2 BTU/hr·ft·°F

Specific Heat Capacity

460 J/kg·K0.11 BTU/lb·°F
435 J/kg·K0.1 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

13.9 µm/m·K7.7 µin/in·°F
12.8 µm/m·K7.1 µin/in·°F

Latent Heat of Fusion

285 J/g123 BTU/lb
290 J/g125 BTU/lb

Max Service Temperature (continuous)

1,100°C2,012 °F
650°C1,202 °F

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

1.5 % IACS
1.4 % IACS

Electrical Resistivity

1.16×10⁻⁶ Ω·m45.7 µΩ·in
1.2×10⁻⁶ Ω·m47.2 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.15 V
-0.1 V

Corrosion Resistance

72 / 100
88 / 100

Manufacturability

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

Machinability

25 / 100
14 / 100

Machinability Rating (AISI 1212 = 100 %)

12%
10%

Weldability

78 / 100
55 / 100

Formability (cold)

70 / 100
25 / 100

Castability

40 / 100
—

Brazeability / Solderability

65 / 100
50 / 100

Polishability

70 / 100
75 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

165 MJ/kg70,937 BTU/lb
250 MJ/kg107,481 BTU/lb

Embodied Carbon (primary production)

12.5 kg CO₂/kg
18 kg CO₂/kg

Embodied Water

400 L/kg47.9 gal/lb
320 L/kg38.3 gal/lb

Typical Recycled Content

35%
40%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

85 kN·m/kg
149 kN·m/kg

Specific Stiffness (E / density)

24.9 MN·m/kg
24.5 MN·m/kg

Modulus of Resilience

237 kJ/m³
1,941 kJ/m³

Thermal Diffusivity

2.9 mm²/s
3 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 scaleAlloy 333Inconel 725

Manufacturing and finishing

CapabilityAlloy 333Inconel 725
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

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

Alloy 333 vs Inconel 725 — frequently asked

Is Inconel 725 stronger than Alloy 333?

Yes. Inconel 725 has a typical yield strength of 890 MPa (129 ksi) against 310 MPa (45 ksi) for Alloy 333 — about 187% more. Tensile strength is 1,240 MPa (180 ksi) vs 690 MPa (100 ksi).

Which is cheaper, Alloy 333 or Inconel 725?

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, Alloy 333 or Inconel 725?

Alloy 333. Its machinability rates poor (25/100) against not recommended (14/100) for Inconel 725; for welding the order is Alloy 333 first (very good, 78/100) then Inconel 725 (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Alloy 333 and Inconel 725 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.