Nickel Alloy Inconel 625 vs Inconel 690
Nickel Alloy · grade comparison
Nickel Alloy Inconel 625 and Inconel 690 are both nickel alloy grades. Inconel 625 is the stronger of the two: yield strength 490 MPa (71.1 ksi) against 345 MPa (50 ksi) for Inconel 690, about 42% more; tensile strength follows at 930 MPa (135 ksi) vs 725 MPa (105 ksi). Inconel 625 is harder — 190 HB against 170 HB for Inconel 690 — which matters for wear surfaces and threads. Inconel 690 runs hotter in service (1,050°C vs 650°C continuous) and Inconel 690 conducts heat better (13.5 W/m·K vs 9.8 W/m·K). On the shop floor, Inconel 625 welds better (excellent vs very good) and Inconel 625 sits in a lower cost tier (premium, $$$) than Inconel 690 (high, $$$$).
Inconel 625Choose it when strength drives the design, or when surface hardness matters.
Inconel 690Choose it when the part sees heat.
Inconel 625 vs Inconel 690: 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)
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elongation at Break 45%
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)
Min Service Temperature
Same in both: Latent Heat of Fusion 290 J/g125 BTU/lb
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Castability
Polishability
Same in both: Machinability Rating (AISI 1212 = 100 %) 12% · Formability (cold) 70 / 100 · Brazeability / Solderability 65 / 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
Same in both: Thermal Shock Resistance Index 3
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 | Inconel 625 | Inconel 690 |
|---|---|---|
| CNC machining | Yes | — |
| Sheet metal | Yes | — |
| 3D printing | Yes | — |
| Default condition | O | — |
| Relative cost | $$$ Premium | $$$$ High |
| Min. machined wall | 1.5 mm | — |
| Best machined surface | Ra 1.6 µm | — |
| Electropolishing | Yes | — |
| HVOF Coating | Yes | — |
They share 3 finishes: Gold Plating, Plasma Spray, Silver Plating.
Inconel 625 vs Inconel 690 — frequently asked
Is Inconel 625 stronger than Inconel 690?
Yes. Inconel 625 has a typical yield strength of 490 MPa (71.1 ksi) against 345 MPa (50 ksi) for Inconel 690 — about 42% more. Tensile strength is 930 MPa (135 ksi) vs 725 MPa (105 ksi).
Which is cheaper, Inconel 625 or Inconel 690?
Inconel 625 is the lower-cost material: it sits in the premium tier ($$$) while Inconel 690 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, Inconel 625 or Inconel 690?
Inconel 690, by a small margin. Both rate poor for machinability — 25/100 against 18/100 for Inconel 625; for welding the order is Inconel 625 first (excellent, 88/100) then Inconel 690 (very good, 78/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Inconel 625 and Inconel 690 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.