Titanium Grade 23 (Ti-6Al-4V ELI) · UNS R56401 · W. Nr. 3.7165
Titanium Grade 23 (Ti-6Al-4V ELI) (R56401): composition, properties, fittings and flanges
Titanium Grade 23 (Ti-6Al-4V ELI) (R56401, W. Nr. 3.7165) is Extra-low interstitial alpha-beta titanium alloy. Titanium Grade 23 (Ti-6Al-4V ELI) is specified at Titanium Balance, Aluminium 5.50 - 6.50. Grade 23 is Grade 5 with oxygen and iron cut to extra-low limits, giving better ductility, fracture toughness and fatigue crack…
- UNS
- R56401
- W. Nr.
- 3.7165
- Density
- 4.43 g/cm³ (0.160 lb/in³)
- Key strength
- 860 MPa / 125 ksi
Identification and standards
| Short form | Titanium Grade 23 (Ti-6Al-4V ELI) · UNS R56401 · W. Nr. 3.7165 |
|---|---|
| Classification | Extra-low interstitial alpha-beta titanium alloy |
| UNS | R56401 |
| Werkstoff number | 3.7165 |
| Material family | Titanium Alloys |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Titanium (Ti) | Balance | Matrix |
| Aluminium (Al) | 5.50 - 6.50 | Alpha stabiliser and strength |
| Vanadium (V) | 3.50 - 4.50 | Beta stabiliser and hardenability |
| Oxygen (O) | 0.13 max | Extra-low for toughness |
| Iron (Fe) | 0.25 max | Extra-low for toughness |
| Carbon (C) | 0.08 max | - |
| Nitrogen (N) | 0.03 max | - |
| Hydrogen (H) | 0.0125 max | Hydride control |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (annealed) | 860 MPa / 125 ksi |
|---|---|
| 0.2 % yield strength, min | 795 MPa / 115 ksi |
| Elongation in 2 in, min | 10 % |
| Typical hardness, annealed | 30 - 36 HRC |
| Fracture toughness vs Grade 5 | Higher, with better fatigue crack growth resistance |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 4.43 g/cm³ (0.160 lb/in³) |
|---|---|
| Melting range | 1604 - 1660 °C (2920 - 3020 °F) |
| Modulus of elasticity | 113 GPa (16.4 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 6.7 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 8.6 µm/m·°C |
| Specific heat capacity | 560 J/kg·K |
Specifications by product form
| Forgings & flanges | ASTM B381 Grade F-23 · ASTM F136 · ASME SB-381 |
|---|---|
| Butt weld fittings | ASTM B363 WPT-23 · ASME SB-363 |
| Seamless pipe & tube | ASTM B861 / B338 Grade 23 |
| Plate / sheet / strip | ASTM B265 Grade 23 · ASME SB-265 |
| Bar / rod | ASTM B348 Grade 23 / F136 |
| Welding consumables | ERTi-5 ELI |
| UNS / EN / China | UNS R56401 · W. Nr. 3.7165 · GB TC4ELI |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged flanges blanks and finished flanges to ASME B16.5, B16.47 Series A/B and B16.36
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9 and MSS SP-43
- Seamless pipe and tube to the applicable ASTM / ASME pipe specification
- Forged rings, discs and hubs machined to your drawing
Typical applications
- Orthopaedic and dental implants and surgical instrumentation
- Cryogenic vessels and subsea pressure housings
- Aerospace fracture-critical structures
- High-pressure gas and diving system components
Welding, forming and machining
- Welding
- Weld by GTAW with ERTi-5 ELI filler under full argon shielding. ELI chemistry must be maintained in the filler to keep the toughness advantage.
- Heat treatment
- Anneal at 700 - 785 °C and cool in air; solution treat and age at 900 - 970 °C plus 480 - 595 °C where higher strength is specified.
- Hot and cold forming
- Hot work in the range stated by the mill for this grade, then re-solution or re-age before final machining so that the delivered condition matches the certificate.
- Machining
- Machine with sharp carbide or high-speed steel tooling, positive rake, constant feed and ample coolant. Never dwell - the surface work-hardens quickly.
Buy Titanium Grade 23 (Ti-6Al-4V ELI) from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.