Titanium BT5-1-ELI
Grade
Choose for liquid-hydrogen/liquid-helium hardware where notch toughness at -196 to -253 °C governs.
Values for the ELI condition
Other BT5-1 tempers and conditions
BT5-1 is listed in 5 conditions; see the grade overview at BT5-1.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ELIThis page extra-low-interstitial (low O, N, H) for cryogenic service | Choose for liquid-hydrogen/liquid-helium hardware where notch toughness at -196 to -253 °C governs. | 720 | 790 | 16 | 29 HRC | 8 W/m·K |
AnnealedDefault mill annealed sheet/plate (700–800 °C, air cool) | Standard stocked condition for sheet and plate; best balance of strength, ductility and weld response. | 800 | 860 | 13 | 300 HB | — |
As-welded deposit | Reference condition for weld-joint design; alpha alloy retains near-parent strength but lower ductility. | 800 | 850 | 8 | 33 HRC | 1.1 % IACS |
Stress relieved | Applied after welding, straightening or heavy machining to remove residual stress without softening. | 820 | 880 | 12 | 33 HRC | 1.1 % IACS |
Hot rolled | Lowest-cost mill condition for parts that will be machined and heat treated afterwards. | 840 | 900 | 11 | 34 HRC | 1.1 % IACS |
What is BT5-1-ELI?
BT5-1-ELI is BT5-1 in the ELI grade — choose for liquid-hydrogen/liquid-helium hardware where notch toughness at -196 to -253 °C governs. BT5-1-ELI has a yield strength of 720 MPa (104 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 53% of titanium grades. Elongation at break is 16% and the elastic modulus is 107 GPa (15.5 Msi). BT5-1-ELI has a density of 4.46 g/cm³ (0.161 lb/in³), lighter than 78% of titanium grades. It melts at 1,550°C (2,822 °F). Annealed is the default condition FabDigit quotes; ELI is available on request or by drawing note.
Advantages
- High service temperature — 425°C (797 °F), better than 85% of titanium grades
Limitations
- Hard to polish — 60/100, worse than 97% of titanium grades
BT5-1-ELI properties
Typical room-temperature values for BT5-1-ELI; 21 are specific to this condition. Other listed values are BT5-1 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
BT5-1-ELI has a density of 4.46 g/cm³ (0.161 lb/in³), lighter than 78% of titanium grades. It melts at 1,550°C (2,822 °F).
Mechanical16
BT5-1-ELI has a yield strength of 720 MPa (104 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 53% of titanium grades. Elongation at break is 16% and the elastic modulus is 107 GPa (15.5 Msi).
Thermal6
BT5-1-ELI is rated for continuous service to 425°C (797 °F). It conducts heat at 8 W/m·K (4.62 BTU/hr·ft·°F), better than 51% of titanium grades. Thermal expansion is 9.4 µm/m·K (5.22 µin/in·°F).
Electrical3
BT5-1-ELI conducts electricity at 1.1 % IACS, worse than 67% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), worse than 93% of titanium grades.
Sustainability4
Producing a kilogram of BT5-1-ELI takes about 650 MJ of energy and emits 40 kg of CO₂ — less than 75% of titanium grades. Typical recycled content is 25%.
Manufacturability8
BT5-1-ELI's machinability is poor (24/100, worse than 51% of titanium grades); weldability very good (80/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BT5-1-ELI
Is BT5-1 easy to machine?
Machine like other alpha Ti: rigid setups, sharp uncoated-carbide or coated inserts, low surface speed (25–45 m/min), heavy flood coolant, and never dwell — work hardens and galls readily.
Can BT5-1 be welded?
Good GTAW/plasma/EB weldability with trailing argon or chamber shielding; keep interstitials and moisture out, then stress relieve 540–650 °C; no strengthening heat treatment available.
Can BT5-1 be formed, bent or molded?
Limited cold formability (bend radius ≥4–5t); hot or warm forming at 600–750 °C with subsequent descaling and alpha-case removal is the normal route.
What surface finishes work on BT5-1?
Pickle in HNO₃/HF to strip alpha case and scale; anodic oxide (AMS 2488) or thermal oxidation reduces galling, and shot/glass peening improves fatigue — avoid chloride-bearing marker inks before heat treatment.
BT5-1 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 stabiliser | 4.3 – 6 | 5 |
| Snneutral solid-solution strengthener | 2 – 3 | 2.5 |
| Zrimpurity limit | ≤ 0.3 | — |
| Si | ≤ 0.15 | — |
| Fe≤0.25 for кт/ELI grade | ≤ 0.3 | — |
| O≤0.10 for кт/ELI grade | ≤ 0.15 | — |
| C | ≤ 0.1 | — |
| N≤0.03 for кт/ELI | ≤ 0.05 | — |
| H≤0.008 for кт/ELI | ≤ 0.02 | — |
| Other, eachtotal ≤0.30 | ≤ 0.1 | — |
| Ti | balance | — |
BT5-1-ELI — frequently asked
What is BT5-1-ELI used for?
BT5-1-ELI is typically used for cryogenic tanks, airframe structures and welded assemblies. In short: cryogenic-capable alpha titanium; weldable to 450 °C; ti-5Al-2.5Sn equivalent.
What is the yield strength of BT5-1-ELI?
BT5-1-ELI has a typical yield strength of 720 MPa (104 ksi) and a tensile strength of 790 MPa (115 ksi) — stronger than 53% of titanium grades. Strength varies by condition: see the 5 listed tempers.
Is BT5-1-ELI easy to machine?
Not especially — machinability is rated poor (24/100, worse than 51% of titanium grades). Machine like other alpha Ti: rigid setups, sharp uncoated-carbide or coated inserts, low surface speed (25–45 m/min), heavy flood coolant, and never dwell — work hardens and galls readily.
Can BT5-1-ELI be welded?
Yes — weldability is rated very good (80/100). Good GTAW/plasma/EB weldability with trailing argon or chamber shielding; keep interstitials and moisture out, then stress relieve 540–650 °C; no strengthening heat treatment available.
What surface finishes work on BT5-1-ELI?
Pickle in HNO₃/HF to strip alpha case and scale; anodic oxide (AMS 2488) or thermal oxidation reduces galling, and shot/glass peening improves fatigue — avoid chloride-bearing marker inks before heat treatment.
Can BT5-1-ELI be formed, bent or molded?
Limited cold formability (bend radius ≥4–5t); hot or warm forming at 600–750 °C with subsequent descaling and alpha-case removal is the normal route.
What is the maximum service temperature of BT5-1-ELI?
BT5-1-ELI is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BT5-1 Annealed and BT5-1-ELI?
Annealed is the default condition — standard stocked condition for sheet and plate; best balance of strength, ductility and weld response. ELI: choose for liquid-hydrogen/liquid-helium hardware where notch toughness at -196 to -253 °C governs. Yield strength is 800 MPa in Annealed versus 720 MPa in ELI.
Sources
- GOST 19807 — Titanium and titanium alloys, grades — Gosstandart (1991)
- GOST 22178 — Titanium alloy sheets — Gosstandart (1976)
- ASTM B265 / B348 — Ti and Ti alloy strip, sheet, plate and bar (Grade 6 / Grade 6 ELI) — ASTM International (2020)
- GB/T 3620.1 — Titanium and titanium alloy grades (TA7) — SAC (2016)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (Ti-5Al-2.5Sn) — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- MMPDS-style typical design data for Ti-5Al-2.5Sn sheet and bar — Battelle (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.