Titanium Ti Grade 18
UNS R56322
Ti Grade 18 (UNS R56322, ASTM B265/B338) is a palladium-modified version of Ti-3Al-2.5V (Grade 9) that adds crevice-corrosion resistance while keeping the strength-to-formability balance that makes Grade 9 the standard tubing alloy.
Reference datasheet — Ti Grade 18 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the Annealed condition
Ti Grade 18 tempers and conditions
Ti Grade 18 is supplied in 3 conditions, soft to hard. Annealed is the default FabDigit quotes; the values on this page are for it.
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 | — |
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?
Ti Grade 18 (UNS R56322, ASTM B265/B338) is a palladium-modified version of Ti-3Al-2.5V (Grade 9) that adds crevice-corrosion resistance while keeping the strength-to-formability balance that makes Grade 9 the standard tubing alloy. It is supplied mainly as cold-drawn seamless tube plus bar and sheet in annealed, CWSR and transformed-beta conditions. Annealed values are 570 MPa yield, 690 MPa tensile, 20% elongation, 240 HB (24 HRC) and 103 GPa modulus, with service to 315 °C and a corrosion score of 93/100. Machinability is poor (25/100); use Grade 9 where the corrosive duty does not justify the palladium cost. Ti Grade 18 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). Ti Grade 18 has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 52% of titanium grades. Elongation at break is 20% and the elastic modulus is 103 GPa (14.9 Msi).
What is Ti Grade 18 used for?
- Aircraft hydraulic tubing
- Aerospace pneumatic and fuel lines
- Chemical process tubing in corrosive service
- Instrumentation and sample lines
- Heat exchanger U-tubes
- Seawater service tube assemblies
- Tube fittings and unions
Ti Grade 18 properties
Typical room-temperature values for Ti Grade 18-Annealed; bars are the position among titanium grades.
Physical3
Ti Grade 18 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 has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 52% of titanium grades. Elongation at break is 20% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
Ti Grade 18 is rated for continuous service to 315°C (599 °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 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 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's machinability is poor (25/100, better than 53% of titanium grades); weldability very good (80/100); formability good (60/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the titanium family
Yield strength against density for every titanium grade FabDigit runs. Ti Grade 18 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Ti Grade 18
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.
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 |
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.
Surface treatments FabDigit runs on titanium parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Titanium Ti Grade 18 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R56322
- Also called
- Ti-3Al-2.5V-0.05Pd
How much does Ti Grade 18 cost?
Ti Grade 18 is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Ti Grade 18 — frequently asked
What is Ti Grade 18 used for?
Ti Grade 18 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?
Ti Grade 18 has a typical yield strength of 570 MPa (82.7 ksi) and a tensile strength of 690 MPa (100 ksi) — weaker than 52% of titanium grades. Strength varies by condition: see the 3 listed tempers.
Is Ti Grade 18 easy to machine?
Not especially — machinability is rated poor (25/100, better than 53% 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 be welded?
Yes — weldability is rated very good (80/100). 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?
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 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?
Ti Grade 18 is rated for continuous use to about 315°C (599 °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.
How much does Ti Grade 18 cost?
Ti Grade 18 is a high-cost titanium ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.