Titanium Ti Grade 18-TB (Transformed beta)
Precip hard
UNS R56322
Choose for tubing needing improved creep resistance, hydrogen tolerance and crack-growth resistance at the cost of some tensile ductility.
Values for the TB condition
Other Ti Grade 18 tempers and conditions
Ti Grade 18 is listed in 3 conditions; see the grade overview at Ti Grade 18.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault mill annealed sheet, bar, tube (ASTM B265/B338 Grade 18) | Default stock condition: best ductility and formability for tube bending, flaring and welding at ~620 MPa minimum UTS. | 570 | 690 | 20 | 24 HRC | — |
TBThis page Transformed beta | Choose for tubing needing improved creep resistance, hydrogen tolerance and crack-growth resistance at the cost of some tensile ductility. | 620 | 720 | 12 | 28 HRC | — |
Cold worked and stress relieved | Pick for high-pressure hydraulic and instrument tubing where ~860 MPa UTS and thin walls save weight; reduced ductility for tight bends. | 790 | 900 | 12 | 32 HRC | — |
What is Ti Grade 18-TB?
Ti Grade 18-TB is Ti Grade 18 in the TB condition — choose for tubing needing improved creep resistance, hydrogen tolerance and crack-growth resistance at the cost of some tensile ductility. Ti Grade 18-TB has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 50% of titanium grades. Elongation at break is 12% and the elastic modulus is 102 GPa (14.8 Msi). Ti Grade 18-TB has a density of 4.48 g/cm³ (0.162 lb/in³), lighter than 71% of titanium grades. It melts at 1,650°C (3,002 °F). Annealed is the default condition FabDigit quotes; TB is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 85 MPa·√m (77.4 ksi·√in), better than 91% of titanium grades
Limitations
- Limited ductility — 12%, worse than 78% of titanium grades
Ti Grade 18-TB properties
Typical room-temperature values for Ti Grade 18-TB; 18 are specific to this condition. Other listed values are Ti Grade 18 reference data and may not represent this condition. Bars are the position among titanium grades.
Physical3
Ti Grade 18-TB has a density of 4.48 g/cm³ (0.162 lb/in³), lighter than 71% of titanium grades. It melts at 1,650°C (3,002 °F).
Mechanical16
Ti Grade 18-TB has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 50% of titanium grades. Elongation at break is 12% and the elastic modulus is 102 GPa (14.8 Msi).
Thermal6
Ti Grade 18-TB is rated for continuous service to 370°C (698 °F). It conducts heat at 7.6 W/m·K (4.39 BTU/hr·ft·°F), worse than 59% of titanium grades. Thermal expansion is 9.4 µm/m·K (5.22 µin/in·°F).
Electrical3
Ti Grade 18-TB conducts electricity at 1.4 % IACS, better than 53% of titanium grades.
Chemical & Environmental3
Corrosion resistance is excellent (93/100), better than 72% of titanium grades.
Sustainability4
Producing a kilogram of Ti Grade 18-TB takes about 650 MJ of energy and emits 42 kg of CO₂ — less than 75% of titanium grades. Typical recycled content is 25%.
Manufacturability8
Ti Grade 18-TB's machinability is poor (22/100, worse than 55% of titanium grades); weldability very good (78/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Ti Grade 18-TB
Is Ti Grade 18 easy to machine?
Low speed, heavy positive-rake carbide tooling, high-volume flood coolant and rigid setups; avoid dwelling to prevent work hardening, galling and fire risk from fine chips.
Can Ti Grade 18 be welded?
Readily GTAW/plasma/EB welded with matched or Gr 9 filler under full argon shielding and trailing/back purge; keep oxygen and hydrogen pickup low and stress-relieve heavy joints (≈540–600 °C).
Can Ti Grade 18 be formed, bent or molded?
Alloy of choice for cold-drawn tube: bend and flare in the annealed condition with generous radii and ~15–20 % springback allowance; CWSR and transformed-beta tube need warm forming (200–400 °C) or larger radii.
What surface finishes work on Ti Grade 18?
Pickle in HNO₃/HF to remove alpha case after hot work; anodize (AMS 2488) or apply dry-film lube to combat galling — plating is rarely needed since the passive oxide gives the corrosion protection.
Ti Grade 18 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 | 2.5 – 3.5 | 3 |
| V | 2 – 3 | 2.5 |
| Pdcorrosion-enhancing addition distinguishing Gr 18 from Gr 9 | 0.04 – 0.08 | 0.05 |
| Fe | ≤ 0.25 | — |
| Ooxygen limit per ASTM B265/B338; verify against the ordering standard/product form | ≤ 0.12 | — |
| C | ≤ 0.08 | — |
| N | ≤ 0.03 | — |
| Hlower limits often specified for tube | ≤ 0.02 | — |
| other, eachresidual elements | ≤ 0.1 | — |
| other, totalresidual elements | ≤ 0.4 | — |
| Ti | balance | — |
Ti Grade 18-TB — frequently asked
What is Ti Grade 18-TB used for?
Ti Grade 18-TB is typically used for aircraft hydraulic tubing, aerospace pneumatic and fuel lines, chemical process tubing in corrosive service, instrumentation and sample lines, heat exchanger U-tubes and seawater service tube assemblies. In short: corrosion-resistant Grade 9 tubing; higher strength than CP grades; palladium cost premium.
What is the yield strength of Ti Grade 18-TB?
Ti Grade 18-TB has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 50% of titanium grades. Strength varies by condition: see the 3 listed tempers.
Is Ti Grade 18-TB easy to machine?
Not especially — machinability is rated poor (22/100, worse than 55% of titanium grades). Low speed, heavy positive-rake carbide tooling, high-volume flood coolant and rigid setups; avoid dwelling to prevent work hardening, galling and fire risk from fine chips.
Can Ti Grade 18-TB be welded?
Yes — weldability is rated very good (78/100). Readily GTAW/plasma/EB welded with matched or Gr 9 filler under full argon shielding and trailing/back purge; keep oxygen and hydrogen pickup low and stress-relieve heavy joints (≈540–600 °C).
What surface finishes work on Ti Grade 18-TB?
Pickle in HNO₃/HF to remove alpha case after hot work; anodize (AMS 2488) or apply dry-film lube to combat galling — plating is rarely needed since the passive oxide gives the corrosion protection.
Can Ti Grade 18-TB be formed, bent or molded?
Alloy of choice for cold-drawn tube: bend and flare in the annealed condition with generous radii and ~15–20 % springback allowance; CWSR and transformed-beta tube need warm forming (200–400 °C) or larger radii.
What is the maximum service temperature of Ti Grade 18-TB?
Ti Grade 18-TB is rated for continuous use to about 370°C (698 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Ti Grade 18 Annealed and Ti Grade 18 CWSR?
Annealed is the default condition — default stock condition: best ductility and formability for tube bending, flaring and welding at ~620 MPa minimum UTS. CWSR: pick for high-pressure hydraulic and instrument tubing where ~860 MPa UTS and thin walls save weight; reduced ductility for tight bends. Yield strength is 570 MPa in Annealed versus 790 MPa in CWSR.
Sources
- ASTM B265 — Titanium and Titanium Alloy Strip, Sheet, and Plate — ASTM International (2020)
- ASTM B338 — Seamless and Welded Titanium and Titanium Alloy Tubes for Condensers and Heat Exchangers — ASTM International (2017)
- ASTM B861 / B862 — Titanium and Titanium Alloy Seamless and Welded Pipe — ASTM International (2019)
- AMS 4944 / AMS 4945 — Titanium Alloy Seamless Hydraulic Tubing, 3Al-2.5V, annealed and cold worked stress relieved — SAE International (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- Materials Properties Handbook: Titanium Alloys — ASM International (1994)
- Titanium tube and pipe grade data (Ti-3Al-2.5V / Gr 9 / Gr 18) — Sandvik / Baoji titanium mills (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.