Titanium IMI 834-STA (Solution treated and aged)
Heat-treated state · default condition
Standard disc/forging condition: bimodal structure with ~15 % primary α giving the best balance of strength, LCF life and 600 °C creep.
Values for the STA 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 | — |
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 | — |
STADefaultThis page 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-STA?
IMI 834-STA is IMI 834 heat treated to STA — standard disc/forging condition: bimodal structure with ~15 % primary α giving the best balance of strength, LCF life and 600 °C creep. IMI 834-STA has a yield strength of 910 MPa (132 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 84% of titanium grades. Elongation at break is 12% and the elastic modulus is 120 GPa (17.4 Msi). IMI 834-STA 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).
Advantages
- High service temperature — 600°C (1,112 °F), better than 100% of titanium grades
- Stiff — 120 GPa (17.4 Msi), better than 98% of titanium grades
- High strength — 910 MPa (132 ksi), better than 84% of titanium grades
Limitations
- Low fracture toughness — 50 MPa·√m (45.5 ksi·√in), worse than 96% 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
- Limited ductility — 12%, worse than 78% of titanium grades
IMI 834-STA properties
Typical room-temperature values for IMI 834-STA; 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-STA 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-STA has a yield strength of 910 MPa (132 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 84% of titanium grades. Elongation at break is 12% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
IMI 834-STA is rated for continuous service to 600°C (1,112 °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-STA 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-STA 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-STA's machinability is poor (15/100, worse than 97% of titanium grades); weldability fair (40/100); formability poor (15/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with IMI 834-STA
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-STA — frequently asked
What is IMI 834-STA used for?
IMI 834-STA 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-STA?
IMI 834-STA has a typical yield strength of 910 MPa (132 ksi) and a tensile strength of 1,030 MPa (149 ksi) — stronger than 84% of titanium grades. Strength varies by condition: see the 3 listed tempers.
Is IMI 834-STA easy to machine?
Not especially — machinability is rated poor (15/100, worse than 97% 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-STA 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-STA?
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-STA 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-STA?
IMI 834-STA is rated for continuous use to about 600°C (1,112 °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.