Nickel Alloy Alloy 686 vs Hastelloy X
Nickel Alloy · grade comparison
Nickel Alloy Alloy 686 and Hastelloy X are both nickel alloy grades. Alloy 686 is the stronger of the two: yield strength 380 MPa (55.1 ksi) against 360 MPa (52.2 ksi) for Hastelloy X, about 6% more. Alloy 686 is the more ductile: elongation 60% versus 43% for Hastelloy X. Hastelloy X is lighter (8.22 g/cm³ vs 8.73 g/cm³ for Alloy 686) and Hastelloy X runs hotter in service (1,150°C vs 1,000°C continuous). On the shop floor, Hastelloy X sits in a lower cost tier (premium, $$$) than Alloy 686 (high, $$$$).
Alloy 686Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
Hastelloy XChoose it when weight is the constraint, or when the part sees heat.
Alloy 686 vs Hastelloy X: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Fracture Toughness (K_IC)
Same in both: Shear Modulus 79 GPa11.5 Msi · Fatigue Strength (Endurance Limit) 300 MPa43.5 ksi
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 9.1 W/m·K5.3 BTU/hr·ft·°F · 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).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Castability
Brazeability / Solderability
Polishability
Same in both: Machinability 18 / 100 · Machinability Rating (AISI 1212 = 100 %) 12% · Formability (cold) 70 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 35%
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 686 | Hastelloy X |
|---|---|---|
| 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 686 vs Hastelloy X — frequently asked
Is Alloy 686 stronger than Hastelloy X?
Yes. Alloy 686 has a typical yield strength of 380 MPa (55.1 ksi) against 360 MPa (52.2 ksi) for Hastelloy X — about 6% more. Tensile strength is 760 MPa (110 ksi) vs 755 MPa (110 ksi).
Which is cheaper, Alloy 686 or Hastelloy X?
Hastelloy X is the lower-cost material: it sits in the premium tier ($$$) while Alloy 686 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which welds better, Alloy 686 or Hastelloy X?
Hastelloy X. Its weldability rates excellent (85/100) against very good (80/100) for Alloy 686.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Alloy 686 and Hastelloy X 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.