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Titanium Grade 16 vs IMI 685

Titanium · grade comparison

Titanium Grade 16 and IMI 685 are both titanium grades. IMI 685 is the stronger of the two: yield strength 870 MPa (126 ksi) against 380 MPa (55.1 ksi) for Grade 16, about 129% more; tensile strength follows at 990 MPa (144 ksi) vs 485 MPa (70.3 ksi). In exchange, Grade 16 is the more ductile: elongation 28% versus 11% for IMI 685, and IMI 685 is harder (330 HV vs 160 HV). IMI 685 is stiffer (120 GPa vs 105 GPa) and IMI 685 runs hotter in service (520°C vs 315°C continuous). On the shop floor, Grade 16 machines more easily (fair vs poor) and Grade 16 welds better (excellent vs fair).

Grade 16Choose 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 16 vs IMI 685: properties

Grade 16IMI 685

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

105 GPa15.2 Msi
120 GPa17.4 Msi

Poisson's Ratio

0.34
0.32

Tensile Strength (Ultimate)

485 MPa70.3 ksi
990 MPa144 ksi

Yield Strength (0.2% offset)

380 MPa55.1 ksi
870 MPa126 ksi

Elongation at Break

28%
11%

Reduction in Area

45%
20%

Compressive Strength

400 MPa58 ksi
900 MPa131 ksi

Shear Strength

310 MPa45 ksi
620 MPa89.9 ksi

Fatigue Strength (Endurance Limit)

280 MPa40.6 ksi
500 MPa72.5 ksi

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
15 J11.1 ft·lbf

Hardness, Brinell

150 HB
—

Hardness, Rockwell B

80 HRB
—

Hardness, Vickers

160 HV
330 HV

Hardness, Rockwell C

—
33 HRC

Same in both: Shear Modulus 45 GPa6.5 Msi · Bulk Modulus 110 GPa16 Msi · Fracture Toughness (K_IC) 70 MPa·√m63.7 ksi·√in

Physical

Density and transition temperatures.

Density

4.51 g/cm³0.16 lb/in³
4.45 g/cm³0.16 lb/in³

Melting Point (Solidus)

1,660°C3,020 °F
1,600°C2,912 °F

Liquidus Temperature

1,670°C3,038 °F
1,660°C3,020 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

17 W/m·K9.8 BTU/hr·ft·°F
7 W/m·K4 BTU/hr·ft·°F

Specific Heat Capacity

523 J/kg·K0.12 BTU/lb·°F
530 J/kg·K0.13 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

8.6 µm/m·K4.8 µin/in·°F
9.3 µm/m·K5.2 µin/in·°F

Latent Heat of Fusion

295 J/g127 BTU/lb
365 J/g157 BTU/lb

Max Service Temperature (continuous)

315°C599 °F
520°C968 °F

Min Service Temperature

-196°C-321 °F
-100°C-148 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

3.1 % IACS
1.1 % IACS

Electrical Resistivity

5.6×10⁻⁷ Ω·m22 µΩ·in
1.6×10⁻⁶ Ω·m63 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.05 V
-0.12 V

Corrosion Resistance

96 / 100
86 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

38 / 100
18 / 100

Machinability Rating (AISI 1212 = 100 %)

35%
16%

Weldability

88 / 100
45 / 100

Formability (cold)

75 / 100
20 / 100

Brazeability / Solderability

40 / 100
35 / 100

Polishability

70 / 100
60 / 100

Castability

—
30 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

620 MJ/kg266,552 BTU/lb
650 MJ/kg279,450 BTU/lb

Embodied Carbon (primary production)

38 kg CO₂/kg
40 kg CO₂/kg

Embodied Water

500 L/kg59.9 gal/lb
600 L/kg71.9 gal/lb

Typical Recycled Content

25%
15%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

108 kN·m/kg
222 kN·m/kg

Specific Stiffness (E / density)

23.3 MN·m/kg
27 MN·m/kg

Modulus of Resilience

688 kJ/m³
3,154 kJ/m³

Thermal Diffusivity

7.2 mm²/s
3 mm²/s

Thermal Shock Resistance Index

9
6

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.

3005007001,0004.555.5Density (g/cm³)Yield strength (MPa) — log scaleGrade 16IMI 685

Manufacturing and finishing

CapabilityGrade 16IMI 685
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Both take the same 1 finish: Plasma Spray.

Grade 16 vs IMI 685 — frequently asked

Is IMI 685 stronger than Grade 16?

Yes. IMI 685 has a typical yield strength of 870 MPa (126 ksi) against 380 MPa (55.1 ksi) for Grade 16 — about 129% more. Tensile strength is 990 MPa (144 ksi) vs 485 MPa (70.3 ksi).

Which is cheaper, Grade 16 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 16 or IMI 685?

Grade 16. Its machinability rates fair (38/100) against poor (18/100) for IMI 685; for welding the order is Grade 16 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 16 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.