Titanium Ti-15-3-O vs Ti-15-3-STA
Titanium · Ti-15-3 temper comparison
Ti-15-3-O and Ti-15-3-STA are two conditions of the same titanium grade, Ti-15-3: O (annealed) versus STA (solution treated and aged). The chemistry is identical, so every difference below comes from the condition. Ti-15-3-STA is the stronger of the two: yield strength 1,240 MPa (180 ksi) against 790 MPa (115 ksi) for Ti-15-3-O, about 57% more; tensile strength follows at 1,300 MPa (189 ksi) vs 820 MPa (119 ksi). In exchange, Ti-15-3-O is the more ductile: elongation 20% versus 7% for Ti-15-3-STA, and Ti-15-3-STA is harder (43 HRC vs 27 HRC). Ti-15-3-STA is stiffer (103 GPa vs 82 GPa) and Ti-15-3-STA runs hotter in service (315°C vs 260°C continuous). On the shop floor, Ti-15-3-O welds better (very good vs fair).
Ti-15-3-OChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
Ti-15-3-STAChoose it when strength drives the design, or when the part sees heat.
Ti-15-3-O vs Ti-15-3-STA: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 31 GPa4.5 Msi · Bulk Modulus 110 GPa16 Msi · Poisson's Ratio 0.31 · Compressive Strength 810 MPa117 ksi · Hardness, Brinell 265 HB
Physical
Density and transition temperatures.
Same in both: Density 4.76 g/cm³0.17 lb/in³ · Melting Point (Solidus) 1,600°C2,912 °F · Liquidus Temperature 1,650°C3,002 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 8.1 W/m·K4.7 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 8.5 µm/m·K4.7 µin/in·°F · Latent Heat of Fusion 365 J/g157 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 1.2 % IACS · Electrical Resistivity 1.4×10⁻⁶ Ω·m55.1 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.1 V · Corrosion Resistance 88 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 16% · Brazeability / Solderability 45 / 100 · Polishability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 750 MJ/kg322,442 BTU/lb · Embodied Carbon (primary production) 48 kg CO₂/kg · Embodied Water 600 L/kg71.9 gal/lb · Typical Recycled Content 20%
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.
Ti-15-3-O vs Ti-15-3-STA — frequently asked
Is Ti-15-3-STA stronger than Ti-15-3-O?
Yes. Ti-15-3-STA has a typical yield strength of 1,240 MPa (180 ksi) against 790 MPa (115 ksi) for Ti-15-3-O — about 57% more. Tensile strength is 1,300 MPa (189 ksi) vs 820 MPa (119 ksi).
Which condition does FabDigit quote by default, O or STA?
O is the default Ti-15-3 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, Ti-15-3-O or Ti-15-3-STA?
Ti-15-3-O. Its machinability rates poor (20/100) against not recommended (14/100) for Ti-15-3-STA; for welding the order is Ti-15-3-O first (very good, 70/100) then Ti-15-3-STA (fair, 40/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Ti-15-3-O and Ti-15-3-STA 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.