Nickel Alloy Alloy 689 vs Inconel 718
Nickel Alloy · grade comparison
Nickel Alloy Alloy 689 and Inconel 718 are both nickel alloy grades. Alloy 689 is the stronger of the two: yield strength 840 MPa (122 ksi) against 550 MPa (79.8 ksi) for Inconel 718, about 53% more; tensile strength follows at 1,240 MPa (180 ksi) vs 965 MPa (140 ksi). In exchange, Inconel 718 is the more ductile: elongation 45% versus 16% for Alloy 689, and Alloy 689 is harder (331 HB vs 200 HB). Alloy 689 runs hotter in service (815°C vs 540°C continuous). On the shop floor, Inconel 718 welds better (very good vs poor) and Inconel 718 sits in a lower cost tier (premium, $$$) than Alloy 689 (high, $$$$).
Alloy 689Choose it when strength drives the design, or when the part sees heat.
Inconel 718Choose it when the part is bent, formed or impact-loaded, or when it will be welded.
Alloy 689 vs Inconel 718: 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
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Fracture Toughness (K_IC)
Hardness, Rockwell B
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)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
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)
Brazeability / Solderability
Polishability
Same in both: Castability 45 / 100
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 718 |
|---|---|---|
| CNC machining | — | Yes |
| Sheet metal | — | Yes |
| 3D printing | — | Yes |
| Default condition | — | Solution Annealed |
| Relative cost | $$$$ High | $$$ Premium |
| Min. machined wall | — | 1.5 mm |
| Best machined surface | — | Ra 1.6 µm |
| Electropolishing | — | Yes |
| HVOF Coating | — | Yes |
They share 3 finishes: Gold Plating, Plasma Spray, Silver Plating.
Alloy 689 vs Inconel 718 — frequently asked
Is Alloy 689 stronger than Inconel 718?
Yes. Alloy 689 has a typical yield strength of 840 MPa (122 ksi) against 550 MPa (79.8 ksi) for Inconel 718 — about 53% more. Tensile strength is 1,240 MPa (180 ksi) vs 965 MPa (140 ksi).
Which is cheaper, Alloy 689 or Inconel 718?
Inconel 718 is the lower-cost material: it sits in the premium tier ($$$) while Alloy 689 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, Alloy 689 or Inconel 718?
Inconel 718. Its machinability rates poor (18/100) against not recommended (13/100) for Alloy 689; for welding the order is Inconel 718 first (very good, 70/100) then Alloy 689 (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Alloy 689 and Inconel 718 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.