Titanium Ti-15Mo-2.7Nb-3Al-0.2Si STA-595
Precip hard
UNS R58210
STA-595 = sTA 595 °C
Choose when thermal stability up to ~600 °C, creep resistance and better ductility/toughness matter more than peak tensile strength.
Values for the STA-595 condition
Other Ti-15Mo-2.7Nb-3Al-0.2Si tempers and conditions
Ti-15Mo-2.7Nb-3Al-0.2Si is listed in 4 conditions; see the grade overview at Ti-15Mo-2.7Nb-3Al-0.2Si.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STDefault Solution annealed | Standard as-supplied condition for sheet, foil and bar: soft, ductile, cold-formable and weldable, aged after fabrication if strength is required. | 810 | 840 | 18 | 28 HRC | — |
Cold rolled | Cold-rolled thin strip and MMC matrix foil (0.1–0.3 mm) supplied work-hardened; solution treat or age after lay-up/consolidation. | 950 | 1,000 | 8 | 33 HRC | 1.3 % IACS |
STA-595This page STA 595 °C | Choose when thermal stability up to ~600 °C, creep resistance and better ductility/toughness matter more than peak tensile strength. | 1,050 | 1,140 | 9 | 37 HRC | — |
STA 538 °C | Pick for maximum room- and elevated-temperature strength in airframe/engine parts once forming and welding are complete. | 1,210 | 1,310 | 6 | 41 HRC | — |
What is Ti-15Mo-2.7Nb-3Al-0.2Si STA-595?
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 is Ti-15Mo-2.7Nb-3Al-0.2Si in the STA-595 condition — choose when thermal stability up to ~600 °C, creep resistance and better ductility/toughness matter more than peak tensile strength. Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,140 MPa (165 ksi) — stronger than 96% of titanium grades. Elongation at break is 9% and the elastic modulus is 98 GPa (14.2 Msi). Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 has a density of 4.94 g/cm³ (0.178 lb/in³), heavier than 97% of titanium grades. It melts at 1,600°C (2,912 °F). ST is the default condition FabDigit quotes; STA-595 is available on request or by drawing note.
Advantages
- High service temperature — 595°C (1,103 °F), better than 100% of titanium grades
- High strength — 1,050 MPa (152 ksi), better than 96% of titanium grades
Limitations
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 98% of titanium grades
- Limited ductility — 9%, worse than 97% of titanium grades
- Difficult to weld — 60/100, worse than 83% of titanium grades
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 properties
Typical room-temperature values for Ti-15Mo-2.7Nb-3Al-0.2Si STA-595; 12 are specific to this condition. Other listed values are Ti-15Mo-2.7Nb-3Al-0.2Si reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 has a density of 4.94 g/cm³ (0.178 lb/in³), heavier than 97% of titanium grades. It melts at 1,600°C (2,912 °F).
Mechanical14
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 has a yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,140 MPa (165 ksi) — stronger than 96% of titanium grades. Elongation at break is 9% and the elastic modulus is 98 GPa (14.2 Msi).
Thermal6
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 is rated for continuous service to 595°C (1,103 °F). It conducts heat at 7.6 W/m·K (4.39 BTU/hr·ft·°F), worse than 59% of titanium grades. Thermal expansion is 7.7 µm/m·K (4.28 µin/in·°F).
Electrical3
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 conducts electricity at 1.3 % IACS, worse than 51% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 53% of titanium grades.
Sustainability4
Producing a kilogram of Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 takes about 700 MJ of energy and emits 42 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 15%.
Manufacturability8
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595's machinability is poor (16/100, worse than 93% of titanium grades); weldability good (60/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Ti-15Mo-2.7Nb-3Al-0.2Si STA-595
Is Ti-15Mo-2.7Nb-3Al-0.2Si easy to machine?
Machine like a tough β-Ti alloy: rigid setups, sharp uncoated carbide or PVD-coated tools, low surface speed (15–30 m/min aged), heavy positive rake, generous flood coolant to counter the 7.6 W/m·K conductivity; avoid dwelling and rubbing which work-hardens the surface.
Can Ti-15Mo-2.7Nb-3Al-0.2Si be welded?
GTAW, plasma and EB/laser welding are practical in the solution-treated condition with full inert-gas or vacuum shielding; welds age-harden with the parent but ductility drops, so post-weld solution treat + age (or age only) and avoid welding fully aged material.
Can Ti-15Mo-2.7Nb-3Al-0.2Si be formed, bent or molded?
Excellent cold formability for a high-strength Ti alloy in the ST condition — cold rollable to thin foil, brake-formable with generous radii and ~2–3× springback allowance; hot form/superplastically form 700–815 °C, then age.
What surface finishes work on Ti-15Mo-2.7Nb-3Al-0.2Si?
Pickle in HNO3/HF after hot work to remove alpha case; Ti anodize (AMS 2488) or oxide/MoS2 coatings for galling control; grit blast + primer for painting; takes a good mechanical polish but is prone to galling against itself, so use dry-film lube or plating on threads.
Ti-15Mo-2.7Nb-3Al-0.2Si chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Moβ stabilizer, oxidation/acid resistance | 14 – 16 | 15 |
| Nb | 2.2 – 3.2 | 2.7 |
| Al | 2.5 – 3.5 | 3 |
| Sicreep and oxidation resistance | 0.15 – 0.25 | 0.2 |
| Fe | ≤ 0.4 | — |
| O | ≤ 0.17 | — |
| C | ≤ 0.05 | — |
| N | ≤ 0.05 | — |
| Hmax, sheet/strip | ≤ 0.02 | — |
| Y | ≤ 0.01 | — |
| Other, eachresidual elements, 0.40 max total | ≤ 0.1 | — |
| Ti | balance | — |
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 — frequently asked
What is Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 used for?
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 is typically used for exhaust system components, MMC matrix and high-temperature airframe parts. In short: most oxidation-resistant beta Ti; 480 °C service capability; cold-rollable to foil.
What is the yield strength of Ti-15Mo-2.7Nb-3Al-0.2Si STA-595?
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 has a typical yield strength of 1,050 MPa (152 ksi) and a tensile strength of 1,140 MPa (165 ksi) — stronger than 96% of titanium grades. Strength varies by condition: see the 4 listed tempers.
Is Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 easy to machine?
Not especially — machinability is rated poor (16/100, worse than 93% of titanium grades). Machine like a tough β-Ti alloy: rigid setups, sharp uncoated carbide or PVD-coated tools, low surface speed (15–30 m/min aged), heavy positive rake, generous flood coolant to counter the 7.6 W/m·K conductivity; avoid dwelling and rubbing which work-hardens the surface.
Can Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 be welded?
Yes — weldability is rated good (60/100). GTAW, plasma and EB/laser welding are practical in the solution-treated condition with full inert-gas or vacuum shielding; welds age-harden with the parent but ductility drops, so post-weld solution treat + age (or age only) and avoid welding fully aged material.
What surface finishes work on Ti-15Mo-2.7Nb-3Al-0.2Si STA-595?
Pickle in HNO3/HF after hot work to remove alpha case; Ti anodize (AMS 2488) or oxide/MoS2 coatings for galling control; grit blast + primer for painting; takes a good mechanical polish but is prone to galling against itself, so use dry-film lube or plating on threads.
Can Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 be formed, bent or molded?
Excellent cold formability for a high-strength Ti alloy in the ST condition — cold rollable to thin foil, brake-formable with generous radii and ~2–3× springback allowance; hot form/superplastically form 700–815 °C, then age.
What is the maximum service temperature of Ti-15Mo-2.7Nb-3Al-0.2Si STA-595?
Ti-15Mo-2.7Nb-3Al-0.2Si STA-595 is rated for continuous use to about 595°C (1,103 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Ti-15Mo-2.7Nb-3Al-0.2Si-ST and Ti-15Mo-2.7Nb-3Al-0.2Si STA-538?
ST is the default condition — standard as-supplied condition for sheet, foil and bar: soft, ductile, cold-formable and weldable, aged after fabrication if strength is required. STA-538: pick for maximum room- and elevated-temperature strength in airframe/engine parts once forming and welding are complete. Yield strength is 810 MPa in ST versus 1,210 MPa in STA-538.
Sources
- ASTM B265 / B348 — Titanium Grade 21 (UNS R58210) — ASTM International (2020)
- TIMETAL 21S (Beta 21S) alloy data sheet — TIMET (2000)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- MMPDS / MIL-HDBK-5 titanium alloy chapters (typical values) — Battelle/FAA (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.