Titanium IMI 834 BSTA
Heat-treated state
BSTA = β-STA
Fully transformed (Widmanstätten/colony) structure for maximum creep resistance and crack-growth resistance in blades and thick sections; pay with lower ductility and LCF life.
Values for the BSTA condition
Other IMI 834 tempers and conditions
IMI 834 is listed in 3 conditions; see the grade overview at IMI 834.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest supply condition for bar, sheet and machining stock; use when parts will be re-solution treated and aged after forming or machining. | 850 | 960 | 14 | 32 HRC | — |
BSTAThis page Β-STA | Fully transformed (Widmanstätten/colony) structure for maximum creep resistance and crack-growth resistance in blades and thick sections; pay with lower ductility and LCF life. | 880 | 990 | 8 | 33 HRC | — |
STADefault Solution treated and aged | Standard disc/forging condition: bimodal structure with ~15 % primary α giving the best balance of strength, LCF life and 600 °C creep. | 910 | 1,030 | 12 | 34 HRC | — |
What is IMI 834 BSTA?
IMI 834 BSTA is IMI 834 heat treated to BSTA — fully transformed (Widmanstätten/colony) structure for maximum creep resistance and crack-growth resistance in blades and thick sections; pay with lower ductility and LCF life. IMI 834 BSTA has a yield strength of 880 MPa (128 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 78% of titanium grades. Elongation at break is 8% and the elastic modulus is 120 GPa (17.4 Msi). IMI 834 BSTA has a density of 4.55 g/cm³ (0.164 lb/in³), heavier than 84% of titanium grades. It melts at 1,550°C (2,822 °F). STA is the default condition FabDigit quotes; BSTA is available on request or by drawing note.
Advantages
- High service temperature — 610°C (1,130 °F), better than 101% of titanium grades
- Stiff — 120 GPa (17.4 Msi), better than 98% of titanium grades
- High strength — 880 MPa (128 ksi), better than 78% of titanium grades
Limitations
- Difficult to machine — 14/100, worse than 100% of titanium grades
- Limited ductility — 8%, worse than 99% of titanium grades
- Difficult to weld — 40/100, worse than 94% of titanium grades
- Limited formability — 15/100, worse than 93% of titanium grades
- Low electrical conductivity — 1 % IACS, worse than 89% of titanium grades
IMI 834 BSTA properties
Typical room-temperature values for IMI 834 BSTA; 10 are specific to this condition. Other listed values are IMI 834 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
IMI 834 BSTA has a density of 4.55 g/cm³ (0.164 lb/in³), heavier than 84% of titanium grades. It melts at 1,550°C (2,822 °F).
Mechanical16
IMI 834 BSTA has a yield strength of 880 MPa (128 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 78% of titanium grades. Elongation at break is 8% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
IMI 834 BSTA is rated for continuous service to 610°C (1,130 °F). It conducts heat at 7 W/m·K (4.04 BTU/hr·ft·°F), worse than 76% of titanium grades. Thermal expansion is 9.7 µm/m·K (5.39 µin/in·°F).
Electrical3
IMI 834 BSTA conducts electricity at 1 % IACS, worse than 89% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), worse than 93% of titanium grades.
Sustainability4
Producing a kilogram of IMI 834 BSTA takes about 700 MJ of energy and emits 45 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 10%.
Manufacturability6
IMI 834 BSTA's machinability is not recommended (14/100, worse than 100% of titanium grades); weldability fair (40/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with IMI 834 BSTA
Is IMI 834 easy to machine?
Very difficult: low thermal conductivity plus silicides cause rapid tool wear — use rigid setups, sharp uncoated carbide, 20–40 m/min, heavy flood coolant and positive feed to avoid work hardening and smearing.
Can IMI 834 be welded?
GTAW/plasma/electron-beam weldable with full inert shielding or vacuum, but weld and HAZ lose ductility; a 600–700 °C post-weld stress relief is mandatory and welds are generally avoided in rotating disc hardware.
Can IMI 834 be formed, bent or molded?
Hot work only — isothermal/near-isothermal forging in the α+β field (~950–1010 °C) with tight temperature control, since primary α content and hence creep life depend directly on the final solution temperature.
What surface finishes work on IMI 834?
Grind/chem-mill to remove alpha case after hot work; shot peening is standard for LCF life, and blue-etch anodize plus FPI are used for crack detection; no protective anodic coating is expected.
IMI 834 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 |
|---|---|---|
| Alα stabiliser, main strengthener | 5.5 – 6.1 | 5.8 |
| Sn | 3.5 – 4.5 | 4 |
| Zr | 3 – 4 | 3.5 |
| Nboxidation resistance | 0.5 – 0.9 | 0.7 |
| Moβ stabiliser | 0.25 – 0.75 | 0.5 |
| Sicreep resistance via silicide precipitation | 0.2 – 0.6 | 0.35 |
| Cwidens the heat-treatment window (primary α control) | 0.04 – 0.08 | 0.06 |
| O | ≤ 0.15 | 0.1 |
| Fe | ≤ 0.05 | — |
| N | ≤ 0.03 | — |
| H | ≤ 0.01 | — |
| Ti | balance | — |
IMI 834 BSTA — frequently asked
What is IMI 834 BSTA used for?
IMI 834 BSTA is typically used for jet engine turbine discs, compressor discs, HP compressor drums and spools, blade and blisk forgings, engine rings and spacers and hot-section shafts. In short: highest-temperature near-alpha disc alloy; creep resistance to 600 °C; hardest near-alpha to machine.
What is the yield strength of IMI 834 BSTA?
IMI 834 BSTA has a typical yield strength of 880 MPa (128 ksi) and a tensile strength of 990 MPa (144 ksi) — stronger than 78% of titanium grades. Strength varies by condition: see the 3 listed tempers.
Is IMI 834 BSTA easy to machine?
Not especially — machinability is rated not recommended (14/100, worse than 100% of titanium grades). Very difficult: low thermal conductivity plus silicides cause rapid tool wear — use rigid setups, sharp uncoated carbide, 20–40 m/min, heavy flood coolant and positive feed to avoid work hardening and smearing.
Can IMI 834 BSTA be welded?
With care — weldability is rated fair (40/100). GTAW/plasma/electron-beam weldable with full inert shielding or vacuum, but weld and HAZ lose ductility; a 600–700 °C post-weld stress relief is mandatory and welds are generally avoided in rotating disc hardware.
What surface finishes work on IMI 834 BSTA?
Grind/chem-mill to remove alpha case after hot work; shot peening is standard for LCF life, and blue-etch anodize plus FPI are used for crack detection; no protective anodic coating is expected.
Can IMI 834 BSTA be formed, bent or molded?
Hot work only — isothermal/near-isothermal forging in the α+β field (~950–1010 °C) with tight temperature control, since primary α content and hence creep life depend directly on the final solution temperature.
What is the maximum service temperature of IMI 834 BSTA?
IMI 834 BSTA is rated for continuous use to about 610°C (1,130 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between IMI 834-STA and IMI 834-ANN?
STA is the default condition — standard disc/forging condition: bimodal structure with ~15 % primary α giving the best balance of strength, LCF life and 600 °C creep. ANN: softest supply condition for bar, sheet and machining stock; use when parts will be re-solution treated and aged after forming or machining. Yield strength is 910 MPa in STA versus 850 MPa in ANN.
Sources
- TIMETAL 834 high-temperature near-alpha titanium alloy data sheet — Titanium Metals Corporation (TIMET) (2000)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- CES EduPack titanium alloy eco-property records — Ansys Granta (2023)
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.