Titanium BT5-SR (Stress relieved)
Heat-treated state
GB BT5
Apply 480-600 °C stress relief after welding or rough machining to improve dimensional stability while holding strength at 750 MPa yield and 840 MPa tensile.
Values for the SR condition
Other BT5 tempers and conditions
BT5 is listed in 6 conditions; see the grade overview at BT5.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cast version (ВТ5Л), annealed | Choose the annealed cast version of the same chemistry for complex housings and valve bodies, accepting 700 MPa tensile and 7% elongation, below the wrought product. | 620 | 700 | 7 | 25 HRC | 1.1 % IACS |
Forging / Ring, Annealed | Use die and ring forgings delivered in the annealed state for load-carrying joints, casings and flanges; the coarser forged structure gives 710 MPa yield and 13% elongation. | 710 | 800 | 13 | 26 HRC | 1.1 % IACS |
As-welded deposit | Use these as-welded GTAW or EBW joint values on annealed base metal when qualifying welded structures; single-phase alpha weld strength stays near parent, but elongation drops to 8%. | 720 | 800 | 8 | 30 HRC | 1.1 % IACS |
AnnealedDefault 700–800 °C anneal, air cooled (standard supply condition) | Take the default 700-800 °C annealed, air-cooled condition for most structural parts: 830 MPa tensile with 13% elongation and good weldability. | 740 | 830 | 13 | 28 HRC | — |
SRThis page Stress relieved | Apply 480-600 °C stress relief after welding or rough machining to improve dimensional stability while holding strength at 750 MPa yield and 840 MPa tensile. | 750 | 840 | 12 | 29 HRC | 1.1 % IACS |
Hot Rolled / As-Forged (not annealed) | Order hot rolled or as-forged stock only as blank material: tensile is highest at 870 MPa, but residual stress and property scatter are large, so a following anneal is normally required. | 780 | 870 | 11 | 30 HRC | 1.1 % IACS |
What is BT5-SR?
BT5-SR is BT5 heat treated to SR — apply 480-600 °C stress relief after welding or rough machining to improve dimensional stability while holding strength at 750 MPa yield and 840 MPa tensile. BT5-SR has a yield strength of 750 MPa (109 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 54% of titanium grades. Elongation at break is 12% and the elastic modulus is 112 GPa (16.2 Msi). BT5-SR has a density of 4.4 g/cm³ (0.159 lb/in³), lighter than 98% of titanium grades. It melts at 1,600°C (2,912 °F). Annealed is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High service temperature — 400°C (752 °F), better than 78% of titanium grades
Limitations
- Limited ductility — 12%, worse than 78% of titanium grades
BT5-SR properties
Typical room-temperature values for BT5-SR; 22 are specific to this condition. Other listed values are BT5 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
BT5-SR has a density of 4.4 g/cm³ (0.159 lb/in³), lighter than 98% of titanium grades. It melts at 1,600°C (2,912 °F).
Mechanical16
BT5-SR has a yield strength of 750 MPa (109 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 54% of titanium grades. Elongation at break is 12% and the elastic modulus is 112 GPa (16.2 Msi).
Thermal6
BT5-SR is rated for continuous service to 400°C (752 °F). It conducts heat at 8.4 W/m·K (4.85 BTU/hr·ft·°F), better than 53% of titanium grades. Thermal expansion is 8.8 µm/m·K (4.89 µin/in·°F).
Electrical3
BT5-SR conducts electricity at 1.1 % IACS, worse than 67% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), worse than 77% of titanium grades.
Sustainability4
Producing a kilogram of BT5-SR takes about 700 MJ of energy and emits 46 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 25%.
Manufacturability8
BT5-SR's machinability is poor (23/100, worse than 52% of titanium grades); weldability very good (78/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BT5-SR
Is BT5 easy to machine?
Use low speed with high feed, rigid clamping and ample high-pressure coolant. Sharp uncoated carbide tooling works best; avoid frictional heat and work hardening.
Can BT5 be welded?
The single-phase alpha structure has no heat-treatment hardening tendency, so GTAW, plasma and electron-beam weldability are good. Maintain full inert-gas or vacuum shielding throughout and control oxygen and hydrogen contamination strictly.
Can BT5 be formed, bent or molded?
Cold forming shows strong springback and limited ductility, so keep bend radii at or above 4t. Hot or warm forming at 500–700 °C followed by annealing is the preferred route.
What surface finishes work on BT5?
Colour anodising or chemical conversion coating helps prevent galling, and the alloy polishes well. Pickle in nitric–hydrofluoric acid with controlled times to limit hydrogen pickup.
BT5 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 |
|---|---|---|
| Almain alpha stabilizer | 4.3 – 6.2 | 5.2 |
| Feimpurity | ≤ 0.3 | 0.15 |
| Siimpurity | ≤ 0.12 | 0.05 |
| Zrimpurity | ≤ 0.3 | — |
| Ointerstitial element | ≤ 0.2 | 0.12 |
| Cinterstitial element | ≤ 0.1 | 0.05 |
| Ninterstitial element | ≤ 0.05 | 0.03 |
| Hcontrolled to limit hydrogen embrittlement | ≤ 0.02 | 0.01 |
| Other, totalsum of other impurities | ≤ 0.3 | — |
| Ti | balance | — |
BT5-SR — frequently asked
What is BT5-SR used for?
BT5-SR is typically used for airframe components, marine fittings and casting patterns. In short: single-phase alpha titanium; weldable, no hardening response; cast variant VT5L available.
What is the yield strength of BT5-SR?
BT5-SR has a typical yield strength of 750 MPa (109 ksi) and a tensile strength of 840 MPa (122 ksi) — stronger than 54% of titanium grades. Strength varies by condition: see the 6 listed tempers.
Is BT5-SR easy to machine?
Not especially — machinability is rated poor (23/100, worse than 52% of titanium grades). Use low speed with high feed, rigid clamping and ample high-pressure coolant. Sharp uncoated carbide tooling works best; avoid frictional heat and work hardening.
Can BT5-SR be welded?
Yes — weldability is rated very good (78/100). The single-phase alpha structure has no heat-treatment hardening tendency, so GTAW, plasma and electron-beam weldability are good. Maintain full inert-gas or vacuum shielding throughout and control oxygen and hydrogen contamination strictly.
What surface finishes work on BT5-SR?
Colour anodising or chemical conversion coating helps prevent galling, and the alloy polishes well. Pickle in nitric–hydrofluoric acid with controlled times to limit hydrogen pickup.
Can BT5-SR be formed, bent or molded?
Cold forming shows strong springback and limited ductility, so keep bend radii at or above 4t. Hot or warm forming at 500–700 °C followed by annealing is the preferred route.
What is the maximum service temperature of BT5-SR?
BT5-SR is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BT5 Annealed and BT5-VT5L?
Annealed is the default condition — take the default 700-800 °C annealed, air-cooled condition for most structural parts: 830 MPa tensile with 13% elongation and good weldability. VT5L: choose the annealed cast version of the same chemistry for complex housings and valve bodies, accepting 700 MPa tensile and 7% elongation, below the wrought product. Yield strength is 740 MPa in Annealed versus 620 MPa in VT5L.
Sources
- GOST 19807-91 Титан и сплавы титановые деформируемые. Марки — Госстандарт (1991)
- OST 1 90013-81 Сплавы титановые. Марки — МАП СССР (1981)
- ASM Handbook Vol.2: Properties and Selection — Nonferrous Alloys (Titanium) — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- ВИАМ / Авиационные материалы: титановые сплавы — ВИАМ (2012)
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.