Titanium Grade 6-SR (Stress relieved)
Heat-treated state
ASTM Grade 6 · UNS R54520 · EN 3.7115 · GB TA7
Used for cold-drawn tubing and cold-rolled strip where slightly higher strength and straightness are wanted; retained cold work raises yield but cuts ductility.
Values for the SR condition
Other Grade 6 tempers and conditions
Grade 6 is listed in 3 conditions; see the grade overview at Grade 6.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed, extra low interstitial | Pick for cryogenic tankage and structures down to liquid-hydrogen temperature, where the low oxygen/nitrogen content preserves toughness at some loss of room-temperature strength. | 740 | 800 | 18 | 290 HB | — |
ODefault Annealed | Standard stocked condition for sheet, plate, bar and forgings used up to ~480 °C; annealed 700–845 °C and air cooled. | 810 | 860 | 16 | 33 HRC | — |
SRThis page Stress relieved | Used for cold-drawn tubing and cold-rolled strip where slightly higher strength and straightness are wanted; retained cold work raises yield but cuts ductility. | 880 | 930 | 12 | 35 HRC | 1.1 % IACS |
What is Grade 6-SR?
Grade 6-SR is Grade 6 heat treated to SR — used for cold-drawn tubing and cold-rolled strip where slightly higher strength and straightness are wanted; retained cold work raises yield but cuts ductility. Grade 6-SR has a yield strength of 880 MPa (128 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 78% of titanium grades. Elongation at break is 12% and the elastic modulus is 110 GPa (16 Msi). Grade 6-SR has a density of 4.48 g/cm³ (0.162 lb/in³), lighter than 71% of titanium grades. It melts at 1,590°C (2,894 °F). O is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- High strength — 880 MPa (128 ksi), better than 78% of titanium grades
- High service temperature — 400°C (752 °F), better than 78% of titanium grades
Limitations
- Low fracture toughness — 58 MPa·√m (52.8 ksi·√in), worse than 87% of titanium grades
- Limited ductility — 12%, worse than 78% of titanium grades
- Limited formability — 22/100, worse than 78% of titanium grades
Grade 6-SR properties
Typical room-temperature values for Grade 6-SR; 22 are specific to this condition. Other listed values are Grade 6 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
Grade 6-SR has a density of 4.48 g/cm³ (0.162 lb/in³), lighter than 71% of titanium grades. It melts at 1,590°C (2,894 °F).
Mechanical16
Grade 6-SR has a yield strength of 880 MPa (128 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 78% of titanium grades. Elongation at break is 12% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
Grade 6-SR is rated for continuous service to 400°C (752 °F). It conducts heat at 7.8 W/m·K (4.51 BTU/hr·ft·°F), worse than 53% of titanium grades. Thermal expansion is 9.5 µm/m·K (5.28 µin/in·°F).
Electrical3
Grade 6-SR 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 Grade 6-SR takes about 650 MJ of energy and emits 44 kg of CO₂ — less than 75% of titanium grades. Typical recycled content is 25%.
Manufacturability7
Grade 6-SR's machinability is poor (20/100, worse than 68% of titanium grades); weldability very good (70/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Grade 6-SR
Is Grade 6 easy to machine?
Machine like other alpha/alpha-beta titanium: rigid setups, sharp uncoated-carbide or coated carbide tools, low surface speed (~20–40 m/min), heavy feed and flood coolant to avoid work hardening, galling and fire risk from fine chips.
Can Grade 6 be welded?
One of the more weldable titanium alloys — GTAW, plasma, EB and laser welds with matching or Ti-5Al-2.5Sn ELI filler retain good ductility; full inert-gas or vacuum shielding of the weld and heat-affected zone is mandatory, followed by a 540–650 °C stress relief.
Can Grade 6 be formed, bent or molded?
Limited cold formability (large bend radii, high springback); hot forming or creep forming at 480–760 °C is standard, with post-form anneal and pickling to remove alpha case.
What surface finishes work on Grade 6?
Descale by molten-salt/alkaline plus HNO₃-HF pickling to remove alpha case; anodize (AMS 2488) or dry-film lubricate anti-galling surfaces; can be shot peened for fatigue and takes a good mechanical polish.
Grade 6 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 |
|---|---|---|
| Al | 4 – 6 | 5 |
| Sn | 2 – 3 | 2.5 |
| FeELI: 0.25 max | ≤ 0.5 | 0.25 |
| OELI: 0.12 max | ≤ 0.2 | 0.15 |
| CELI: 0.05 max | ≤ 0.08 | 0.03 |
| NELI: 0.035 max | ≤ 0.05 | 0.02 |
| H0.015 max sheet/strip; ELI 0.0125 max | ≤ 0.02 | 0.01 |
| Residuals (each)0.40 max total | ≤ 0.1 | — |
| Ti | balance | — |
Grade 6-SR — frequently asked
What is Grade 6-SR used for?
Grade 6-SR is typically used for cryogenic LH2 tanks, aerospace forgings and structural fittings, rocket engine and turbopump hardware, welded pressure vessel shells, compressor casings and rings and airframe high-temperature brackets. In short: weldable aerospace titanium.
What is the yield strength of Grade 6-SR?
Grade 6-SR has a typical yield strength of 880 MPa (128 ksi) and a tensile strength of 930 MPa (135 ksi) — stronger than 78% of titanium grades. Strength varies by condition: see the 3 listed tempers.
Is Grade 6-SR easy to machine?
Not especially — machinability is rated poor (20/100, worse than 68% of titanium grades). Machine like other alpha/alpha-beta titanium: rigid setups, sharp uncoated-carbide or coated carbide tools, low surface speed (~20–40 m/min), heavy feed and flood coolant to avoid work hardening, galling and fire risk from fine chips.
Can Grade 6-SR be welded?
Yes — weldability is rated very good (70/100). One of the more weldable titanium alloys — GTAW, plasma, EB and laser welds with matching or Ti-5Al-2.5Sn ELI filler retain good ductility; full inert-gas or vacuum shielding of the weld and heat-affected zone is mandatory, followed by a 540–650 °C stress relief.
What surface finishes work on Grade 6-SR?
Descale by molten-salt/alkaline plus HNO₃-HF pickling to remove alpha case; anodize (AMS 2488) or dry-film lubricate anti-galling surfaces; can be shot peened for fatigue and takes a good mechanical polish.
Can Grade 6-SR be formed, bent or molded?
Limited cold formability (large bend radii, high springback); hot forming or creep forming at 480–760 °C is standard, with post-form anneal and pickling to remove alpha case.
What is the maximum service temperature of Grade 6-SR?
Grade 6-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 Grade 6-O and Grade 6-ELI?
O is the default condition — standard stocked condition for sheet, plate, bar and forgings used up to ~480 °C; annealed 700–845 °C and air cooled. ELI: pick for cryogenic tankage and structures down to liquid-hydrogen temperature, where the low oxygen/nitrogen content preserves toughness at some loss of room-temperature strength. Yield strength is 810 MPa in O versus 740 MPa in ELI.
Can FabDigit make parts in Grade 6-SR?
Yes — Grade 6-SR is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B265 — Titanium and Titanium Alloy Strip, Sheet and Plate (Grade 6) — ASTM International (2020)
- ASTM B348 — Titanium and Titanium Alloy Bars and Billets (Grade 6) — ASTM International (2021)
- AMS 4910 / AMS 4909 / AMS 4926 / AMS 4924 — Ti-5Al-2.5Sn sheet and bar, annealed and ELI — SAE International (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 (Ti-5Al-2.5Sn) — Battelle/FAA (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.