Titanium Grade 17 vs IMI 685
Titanium · grade comparison
Titanium Grade 17 and IMI 685 are both titanium grades. IMI 685 is the stronger of the two: yield strength 870 MPa (126 ksi) against 240 MPa (34.8 ksi) for Grade 17, about 3.6 times as much; tensile strength follows at 990 MPa (144 ksi) vs 330 MPa (47.9 ksi). In exchange, Grade 17 is the more ductile: elongation 32% versus 11% for IMI 685, and IMI 685 is harder (330 HV vs 125 HV). IMI 685 is stiffer (120 GPa vs 103 GPa) and IMI 685 runs hotter in service (520°C vs 315°C continuous). On the shop floor, Grade 17 machines more easily (fair vs poor) and Grade 17 welds better (excellent vs fair).
Grade 17Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
IMI 685Choose it when strength drives the design, or when the part sees heat.
Grade 17 vs IMI 685: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all titanium 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 titanium 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
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
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
Hardness, Rockwell C
Same in both: Shear Modulus 45 GPa6.5 Msi · Bulk Modulus 110 GPa16 Msi
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).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
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
Castability
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 titanium grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | Grade 17 | IMI 685 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 1 finish: Plasma Spray.
Grade 17 vs IMI 685 — frequently asked
Is IMI 685 stronger than Grade 17?
Yes. IMI 685 has a typical yield strength of 870 MPa (126 ksi) against 240 MPa (34.8 ksi) for Grade 17 — about 3.6 times as much. Tensile strength is 990 MPa (144 ksi) vs 330 MPa (47.9 ksi).
Which is cheaper, Grade 17 or IMI 685?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, Grade 17 or IMI 685?
Grade 17. Its machinability rates fair (40/100) against poor (18/100) for IMI 685; for welding the order is Grade 17 first (excellent, 88/100) then IMI 685 (fair, 45/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Grade 17 and IMI 685 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.