Titanium Ti-6Al-6V-2Sn-ST (Solution annealed)
Heat-treated state
UNS R56620 · EN 3.7175 · GB TC10
Transient condition supplied for parts that are formed or machined soft-ish and then aged by the user to full STA strength.
Values for the ST condition
Other Ti-6Al-6V-2Sn tempers and conditions
Ti-6Al-6V-2Sn is listed in 5 conditions; see the grade overview at Ti-6Al-6V-2Sn.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
STThis page Solution annealed | Transient condition supplied for parts that are formed or machined soft-ish and then aged by the user to full STA strength. | 900 | 1,000 | 16 | 33 HRC | 1.1 % IACS |
solution anneal ~870 °C + stabilize ~700 °C | Used on sheet and thin plate where improved microstructural uniformity and slightly better toughness/creep stability are wanted over single mill anneal. | 960 | 1,030 | 15 | 35 HRC | — |
AnnealedDefault mill annealed (approx. 705–760 °C, air cool) | Standard stocked condition: best balance of strength, ductility and toughness, and the starting point for forming or later STA. | 980 | 1,050 | 14 | 36 HRC | 7 W/m·K |
As-forged + stress relieved (~595–650 °C) | Heavy forgings and billet supplied stress-relieved for rough machining before final anneal or STA. | 990 | 1,060 | 12 | 36 HRC | 1.1 % IACS |
Solution treated and aged | Pick when maximum strength and hardness are required in sections up to ~50 mm; accept lower ductility, toughness and weldability. | 1,170 | 1,275 | 10 | 42 HRC | 7 W/m·K |
What is Ti-6Al-6V-2Sn-ST?
Ti-6Al-6V-2Sn-ST is Ti-6Al-6V-2Sn heat treated to ST — transient condition supplied for parts that are formed or machined soft-ish and then aged by the user to full STA strength. Ti-6Al-6V-2Sn-ST has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of titanium grades. Elongation at break is 16% and the elastic modulus is 110 GPa (16 Msi). Ti-6Al-6V-2Sn-ST has a density of 4.54 g/cm³ (0.164 lb/in³), heavier than 80% of titanium grades. It melts at 1,690°C (3,074 °F). Annealed is the default condition FabDigit quotes; ST is available on request or by drawing note.
Advantages
- High strength — 900 MPa (131 ksi), better than 82% of titanium grades
Limitations
- Needs corrosion protection — 82/100, worse than 100% of titanium grades
- Difficult to weld — 40/100, worse than 94% of titanium grades
- Poor heat conductor — 6.8 W/m·K (3.93 BTU/hr·ft·°F), worse than 86% of titanium grades
- Low electrical conductivity — 1.1 % IACS, worse than 77% of titanium grades
Ti-6Al-6V-2Sn-ST properties
Typical room-temperature values for Ti-6Al-6V-2Sn-ST; 22 are specific to this condition. Other listed values are Ti-6Al-6V-2Sn reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
Ti-6Al-6V-2Sn-ST has a density of 4.54 g/cm³ (0.164 lb/in³), heavier than 80% of titanium grades. It melts at 1,690°C (3,074 °F).
Mechanical16
Ti-6Al-6V-2Sn-ST has a yield strength of 900 MPa (131 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of titanium grades. Elongation at break is 16% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
Ti-6Al-6V-2Sn-ST is rated for continuous service to 300°C (572 °F). It conducts heat at 6.8 W/m·K (3.93 BTU/hr·ft·°F), worse than 86% of titanium grades. Thermal expansion is 9.1 µm/m·K (5.06 µin/in·°F).
Electrical3
Ti-6Al-6V-2Sn-ST conducts electricity at 1.1 % IACS, worse than 77% of titanium grades.
Chemical & Environmental3
Corrosion resistance is very good (82/100), worse than 100% of titanium grades.
Sustainability4
Producing a kilogram of Ti-6Al-6V-2Sn-ST takes about 690 MJ of energy and emits 45 kg of CO₂ — more than 57% of titanium grades. Typical recycled content is 30%.
Manufacturability8
Ti-6Al-6V-2Sn-ST's machinability is poor (19/100, worse than 78% of titanium grades); weldability fair (40/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Ti-6Al-6V-2Sn-ST
Is Ti-6Al-6V-2Sn easy to machine?
Machine like Ti-6Al-4V but slower: rigid setups, sharp uncoated carbide or PVD-coated tools, surface speeds ~15–30 m/min in STA, heavy flood coolant, no dwelling — chips are pyrophoric and work hardening/galling is severe.
Can Ti-6Al-6V-2Sn be welded?
GTAW/EBW/laser in high-purity argon or vacuum with full backside shielding; weld in the annealed state and post-weld stress relieve — STA welds lose ductility and toughness, so highly loaded joints are usually avoided.
Can Ti-6Al-6V-2Sn be formed, bent or molded?
Hot form or hot size at 700–870 °C; cold forming is limited to gentle bends with generous radii (≥4–5 t) and springback allowance, and forging needs beta-transus control (~945 °C) for the desired alpha morphology.
What surface finishes work on Ti-6Al-6V-2Sn?
Grit blast + chemical (HNO3-HF) pickle to remove alpha case; anodic/oxide colour treatments per AMS 2488 for identification, and dry-film lube or ion-nitride/Cr-plate on threads and bearing faces to stop galling.
Ti-6Al-6V-2Sn 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 |
|---|---|---|
| Alalpha stabilizer | 5 – 6 | 5.5 |
| Vbeta stabilizer | 5 – 6 | 5.5 |
| Sn | 1.5 – 2.5 | 2 |
| FeFe+Cu 0.35–1.0 each, aids hardenability | 0.35 – 1 | 0.6 |
| Cu | 0.35 – 1 | 0.6 |
| O | ≤ 0.2 | 0.12 |
| C | ≤ 0.05 | 0.02 |
| N | ≤ 0.04 | 0.02 |
| Hmax, bar/forging | ≤ 0.02 | 0.01 |
| Ymax, where specified | ≤ 0.01 | — |
| Other, eachresiduals total 0.4 max | ≤ 0.1 | — |
| Ti | balance | — |
Ti-6Al-6V-2Sn-ST — frequently asked
What is Ti-6Al-6V-2Sn-ST used for?
Ti-6Al-6V-2Sn-ST is typically used for aircraft structural forgings, landing gear parts and ordnance components. In short: stronger than Ti-6Al-4V; deep-hardening forging alloy; limited weldability, high cost.
What is the yield strength of Ti-6Al-6V-2Sn-ST?
Ti-6Al-6V-2Sn-ST has a typical yield strength of 900 MPa (131 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 82% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is Ti-6Al-6V-2Sn-ST easy to machine?
Not especially — machinability is rated poor (19/100, worse than 78% of titanium grades). Machine like Ti-6Al-4V but slower: rigid setups, sharp uncoated carbide or PVD-coated tools, surface speeds ~15–30 m/min in STA, heavy flood coolant, no dwelling — chips are pyrophoric and work hardening/galling is severe.
Can Ti-6Al-6V-2Sn-ST be welded?
With care — weldability is rated fair (40/100). GTAW/EBW/laser in high-purity argon or vacuum with full backside shielding; weld in the annealed state and post-weld stress relieve — STA welds lose ductility and toughness, so highly loaded joints are usually avoided.
What surface finishes work on Ti-6Al-6V-2Sn-ST?
Grit blast + chemical (HNO3-HF) pickle to remove alpha case; anodic/oxide colour treatments per AMS 2488 for identification, and dry-film lube or ion-nitride/Cr-plate on threads and bearing faces to stop galling.
Can Ti-6Al-6V-2Sn-ST be formed, bent or molded?
Hot form or hot size at 700–870 °C; cold forming is limited to gentle bends with generous radii (≥4–5 t) and springback allowance, and forging needs beta-transus control (~945 °C) for the desired alpha morphology.
What is the maximum service temperature of Ti-6Al-6V-2Sn-ST?
Ti-6Al-6V-2Sn-ST is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Ti-6Al-6V-2Sn Annealed and Ti-6Al-6V-2Sn-STA?
Annealed is the default condition — standard stocked condition: best balance of strength, ductility and toughness, and the starting point for forming or later STA. STA: pick when maximum strength and hardness are required in sections up to ~50 mm; accept lower ductility, toughness and weldability. Yield strength is 980 MPa in Annealed versus 1,170 MPa in STA.
Sources
- AMS 4978 — Titanium Alloy Bars, Forgings and Rings 6Al-6V-2Sn — SAE International (2018)
- ASTM B348 / B381 — Titanium and Titanium Alloy Bars, Billets and Forgings (Grade R56620) — ASTM International (2021)
- GB/T 2965 / GB/T 16598 — (TC10) — SAC (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- MMPDS — Metallic Materials Properties Development and Standardization — Battelle/FAA (2019)
- Titanium alloy bar and forging datasheets (Ti 6-6-2) — TIMET / ATI / (2022)
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.