Titanium Ti-15Mo-ST vs Ti-15Mo-STA
Titanium · Ti-15Mo temper comparison
Ti-15Mo-ST and Ti-15Mo-STA are two conditions of the same titanium grade, Ti-15Mo: ST (solution annealed) versus STA (solution treated and aged). The chemistry is identical, so every difference below comes from the condition. Ti-15Mo-STA is the stronger of the two: yield strength 1,010 MPa (146 ksi) against 570 MPa (82.7 ksi) for Ti-15Mo-ST, about 77% more; tensile strength follows at 1,100 MPa (160 ksi) vs 760 MPa (110 ksi). In exchange, Ti-15Mo-ST is the more ductile: elongation 22% versus 10% for Ti-15Mo-STA, and Ti-15Mo-STA is harder (38 HRC vs 27 HRC). Ti-15Mo-STA is stiffer (98 GPa vs 78 GPa). On the shop floor, Ti-15Mo-ST welds better (very good vs fair).
Ti-15Mo-STChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
Ti-15Mo-STAChoose it when strength drives the design.
Ti-15Mo-ST vs Ti-15Mo-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
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 29 GPa4.2 Msi · Bulk Modulus 78 GPa11.3 Msi · Poisson's Ratio 0.33 · Compressive Strength 600 MPa87 ksi · Shear Strength 480 MPa69.6 ksi
Physical
Density and transition temperatures.
Same in both: Density 4.96 g/cm³0.18 lb/in³ · Melting Point (Solidus) 1,670°C3,038 °F · Liquidus Temperature 1,700°C3,092 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 8.5 W/m·K4.9 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 8.7 µm/m·K4.8 µin/in·°F · Latent Heat of Fusion 320 J/g138 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 93 / 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 %) 18% · Castability 40 / 100 · Brazeability / Solderability 45 / 100 · Polishability 80 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 700 MJ/kg300,946 BTU/lb · Embodied Carbon (primary production) 45 kg CO₂/kg · Embodied Water 700 L/kg83.9 gal/lb · Typical Recycled Content 5%
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-15Mo-ST vs Ti-15Mo-STA — frequently asked
Is Ti-15Mo-STA stronger than Ti-15Mo-ST?
Yes. Ti-15Mo-STA has a typical yield strength of 1,010 MPa (146 ksi) against 570 MPa (82.7 ksi) for Ti-15Mo-ST — about 77% more. Tensile strength is 1,100 MPa (160 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, ST or STA?
ST is the default Ti-15Mo 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-15Mo-ST or Ti-15Mo-STA?
Ti-15Mo-ST, by a small margin. Both rate poor for machinability — 24/100 against 18/100 for Ti-15Mo-STA; for welding the order is Ti-15Mo-ST first (very good, 72/100) then Ti-15Mo-STA (fair, 50/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Ti-15Mo-ST and Ti-15Mo-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.