Titanium OT4-1-SR (Stress relieved)
Heat-treated state
Specify vacuum stress relief at 550-650 °C after cold forming or welding to remove residual stress and springback and restore ductility to 20% elongation.
Values for the SR condition
Other OT4-1 tempers and conditions
OT4-1 is listed in 4 conditions; see the grade overview at OT4-1.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Use for welded shells and structures above 6 mm thick; hot rolling plus annealing and descaling gives 610 MPa tensile but slightly lower ductility (18%) than sheet. | 480 | 610 | 18 | 195 HB | 2.9 % IACS |
MDefault Thermomechanically controlled processed | Take the most widely stocked condition, vacuum or protective-atmosphere annealed sheet and strip, for cold bending, spinning and welded structures at 510 MPa yield and 24% elongation. | 510 | 640 | 24 | 200 HB | 2.9 % IACS |
SRThis page Stress relieved | Specify vacuum stress relief at 550-650 °C after cold forming or welding to remove residual stress and springback and restore ductility to 20% elongation. | 530 | 650 | 20 | 205 HB | 2.9 % IACS |
Normalized | Pick strain-hardened cold-rolled sheet or strip when stiffness and strength govern and forming is minimal: yield rises to 700 MPa but elongation falls to 8%. | 700 | 780 | 8 | 24 HRC | 2.9 % IACS |
What is OT4-1-SR?
OT4-1-SR is OT4-1 heat treated to SR — specify vacuum stress relief at 550-650 °C after cold forming or welding to remove residual stress and springback and restore ductility to 20% elongation. OT4-1-SR has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 59% of titanium grades. Elongation at break is 20% and the elastic modulus is 110 GPa (16 Msi). OT4-1-SR has a density of 4.55 g/cm³ (0.164 lb/in³), heavier than 84% of titanium grades. It melts at 1,620°C (2,948 °F). M is the default condition FabDigit quotes; SR is available on request or by drawing note.
OT4-1-SR properties
Typical room-temperature values for OT4-1-SR; 22 are specific to this condition. Other listed values are OT4-1 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
OT4-1-SR has a density of 4.55 g/cm³ (0.164 lb/in³), heavier than 84% of titanium grades. It melts at 1,620°C (2,948 °F).
Mechanical16
OT4-1-SR has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 59% of titanium grades. Elongation at break is 20% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
OT4-1-SR is rated for continuous service to 330°C (626 °F). It conducts heat at 11 W/m·K (6.36 BTU/hr·ft·°F), better than 58% of titanium grades. Thermal expansion is 8.3 µm/m·K (4.61 µin/in·°F).
Electrical3
OT4-1-SR conducts electricity at 2.9 % IACS, better than 58% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (88/100), worse than 77% of titanium grades.
Sustainability4
Producing a kilogram of OT4-1-SR takes about 700 MJ of energy and emits 45 kg of CO₂ — more than 74% of titanium grades. Typical recycled content is 25%.
Manufacturability7
OT4-1-SR's machinability is poor (32/100, better than 70% of titanium grades); weldability excellent (88/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with OT4-1-SR
Is OT4-1 easy to machine?
Use low speed with high feed and copious high-pressure coolant. Sharp uncoated carbide or cobalt-bearing HSS tooling works well; avoid frictional heat and work hardening.
Can OT4-1 be welded?
TIG, plasma, electron-beam and spot welding all give good results. Maintain full inert-gas or vacuum shielding, keep surfaces clean, and stress relieve at 550–650 °C after welding if required.
Can OT4-1 be formed, bent or molded?
One of the best cold-forming titanium alloys, with bend radii down to 2–3t. Springback is large so overbend; warm form complex parts at 300–500 °C.
What surface finishes work on OT4-1?
Descale by pickling in HNO₃/HF, then blast or colour anodise as required. Electroplating is not recommended; activate mechanically or chemically before painting.
OT4-1 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-stabilizing element | 1 – 2.5 | 1.7 |
| Mnbeta-stabilizing element | 0.7 – 2 | 1.2 |
| Fe | ≤ 0.3 | — |
| Si | ≤ 0.15 | — |
| Zr | ≤ 0.3 | — |
| C | ≤ 0.1 | — |
| O | ≤ 0.15 | — |
| N | ≤ 0.05 | — |
| Hhydrogen embrittlement sensitive, must be controlled | ≤ 0.01 | — |
| Other, totalsum of other impurities | ≤ 0.3 | — |
| Ti | balance | — |
OT4-1-SR — frequently asked
What is OT4-1-SR used for?
OT4-1-SR is typically used for deep-formed sheet parts, ducting and transition sections, welded sheet assemblies, formed skins and covers, spun and roll-formed tube parts and clamps, shims and shrouds. In short: best cold-forming titanium; bend radii to 2t; lowest strength in family.
What is the yield strength of OT4-1-SR?
OT4-1-SR has a typical yield strength of 530 MPa (76.9 ksi) and a tensile strength of 650 MPa (94.3 ksi) — weaker than 59% of titanium grades. Strength varies by condition: see the 4 listed tempers.
Is OT4-1-SR easy to machine?
Not especially — machinability is rated poor (32/100, better than 70% of titanium grades). Use low speed with high feed and copious high-pressure coolant. Sharp uncoated carbide or cobalt-bearing HSS tooling works well; avoid frictional heat and work hardening.
Can OT4-1-SR be welded?
Yes — weldability is rated excellent (88/100). TIG, plasma, electron-beam and spot welding all give good results. Maintain full inert-gas or vacuum shielding, keep surfaces clean, and stress relieve at 550–650 °C after welding if required.
What surface finishes work on OT4-1-SR?
Descale by pickling in HNO₃/HF, then blast or colour anodise as required. Electroplating is not recommended; activate mechanically or chemically before painting.
Can OT4-1-SR be formed, bent or molded?
One of the best cold-forming titanium alloys, with bend radii down to 2–3t. Springback is large so overbend; warm form complex parts at 300–500 °C.
What is the maximum service temperature of OT4-1-SR?
OT4-1-SR is rated for continuous use to about 330°C (626 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between OT4-1-M and OT4-1-N?
M is the default condition — take the most widely stocked condition, vacuum or protective-atmosphere annealed sheet and strip, for cold bending, spinning and welded structures at 510 MPa yield and 24% elongation. N: pick strain-hardened cold-rolled sheet or strip when stiffness and strength govern and forming is minimal: yield rises to 700 MPa but elongation falls to 8%. Yield strength is 510 MPa in M versus 700 MPa in N.
Sources
- ГОСТ 19807-91 Титан и сплавы титановые деформируемые. Марки — Госстандарт (1991)
- ГОСТ 22178-76 Листы из титана и титановых сплавов — Госстандарт (1976)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Титановые сплавы: свойства и применение (ВИАМ) — ВИАМ (2009)
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.