Nickel Alloy Alloy 689 vs Inconel 725
Nickel Alloy · grade comparison
Nickel Alloy Alloy 689 and Inconel 725 are both nickel alloy grades. Inconel 725 is the stronger of the two: yield strength 890 MPa (129 ksi) against 840 MPa (122 ksi) for Alloy 689, about 6% more. Inconel 725 is the more ductile: elongation 25% versus 16% for Alloy 689. Alloy 689 runs hotter in service (815°C vs 650°C continuous). On the shop floor, Inconel 725 welds better (good vs poor).
Alloy 689Choose it when the part sees heat.
Inconel 725Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
Alloy 689 vs Inconel 725: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all nickel alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all nickel alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Bulk Modulus
Poisson's Ratio
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Compressive Strength
Fracture Toughness (K_IC)
Same in both: Shear Modulus 79 GPa11.5 Msi · Tensile Strength (Ultimate) 1,240 MPa180 ksi · Fatigue Strength (Endurance Limit) 480 MPa69.6 ksi · Hardness, Rockwell C 35 HRC
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
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
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.1 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | Alloy 689 | Inconel 725 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 3 finishes: Gold Plating, Plasma Spray, Silver Plating.
Alloy 689 vs Inconel 725 — frequently asked
Is Inconel 725 stronger than Alloy 689?
Yes. Inconel 725 has a typical yield strength of 890 MPa (129 ksi) against 840 MPa (122 ksi) for Alloy 689 — about 6% more. Tensile strength is 1,240 MPa (180 ksi) vs 1,240 MPa (180 ksi).
Which is cheaper, Alloy 689 or Inconel 725?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which welds better, Alloy 689 or Inconel 725?
Inconel 725. Its weldability rates good (55/100) against poor (30/100) for Alloy 689.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Alloy 689 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.