ASTM F136 Ti-6Al-4V ELI Grade 23 Titanium Bar
- Standard: ASTM F136
- Grade: Ti-6Al-4V ELI (Grade 23)
- UNS: R56401
- Supply form: Round bar or other ordered bar form
- Condition: Annealed, as ordered
- Dia: φ7 ~ φ300 mm
- Typical Medical Bar Length: 2000–3000 mm; cut-to-length available
Customizable sizes are available, while specific product parameters should be confirmed per the applicable standard edition and order.
Product Overview
ASTM F136 Ti-6Al-4V ELI (Grade 23) titanium bar is wrought alpha-beta titanium alloy bar for the manufacture of surgical implants, UNS R56401. ELI means extra-low interstitial. Lower limits on oxygen, iron and other interstitial elements than conventional Ti-6Al-4V improve fracture toughness, fatigue-crack-growth resistance and low-temperature toughness while retaining high specific strength, corrosion resistance and biocompatibility.
The alloy is widely used as precision machining stock for orthopedic, trauma, spinal, dental and other implantable devices. ASTM F136 specifies medical-alloy raw material; the finished implant still requires device-level validation for actual diameter, microstructure, surface integrity, fatigue, cleaning and sterilization, biological evaluation and applicable regulation.
| Specification | Details |
| Medical Standard | ASTM F136 |
| Medical Grades | Gr23 |
| Diameter Range | Ø7 – Ø300 mm |
| Typical Diameters | Ø7, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 120, 150, 200 mm |
| Typical Medical Bar Length | 2000–3000 mm; cut-to-length available |
| Surface / Supply Condition | Hot-rolled black surface / Turned / Ground |
| Precision Tolerance | h6 / h7 / h8 available subject to diameter, finishing process and order confirmation |
Medical-use boundary: ASTM F136-compliant bar is medical-device raw material, not an approved finished implant. The device manufacturer remains responsible for design, manufacturing, surface treatment, cleaning, sterilization, biological evaluation, risk management and regulatory compliance.
Main Characteristics
- Medical Ti-6Al-4V ELI: Lower maximum levels of oxygen, iron, carbon, nitrogen and hydrogen improve damage tolerance while preserving the high strength of Ti-6Al-4V, making the alloy suitable for implant devices sensitive to fatigue and fracture performance.
- Controlled alpha-beta chemistry: Aluminum stabilizes alpha and vanadium stabilizes beta. Al, V and interstitial elements require heat-specific control for consistent strength, ductility, microstructure and processing response.
- Good biocompatibility: A stable TiO2 passive film and extensive clinical use support its role as a common implant material. The finished device still requires biological evaluation under applicable regulations and standards such as ISO 10993.
- Good corrosion resistance: Performance is generally excellent in saline, body fluids and many chloride environments, but fretting, crevices, dissimilar-metal coupling, fluoride media and surface contamination require device-level evaluation.
- Weldable with strict shielding: Qualified GTAW/TIG, laser, electron-beam or resistance welding may be used. The pool, root and hot heat-affected zone must be fully protected from O, N, H and C contamination.
- High strength with limited cold formability: Room-temperature strength is substantially above unalloyed titanium, but cold-forming margin is limited and springback is significant. Complex forming normally uses warm or hot forming, staged deformation and, when needed, intermediate annealing with device-level validation.
Chemical Composition
The following mass-percent limits apply to ASTM F136 Ti-6Al-4V ELI (UNS R56401). Formal purchasing and acceptance are governed by the contract edition, official standard and producer certified report.
| Element | ASTM F136 Ti-6Al-4V ELI requirement |
| Nitrogen, N | ≤0.05% |
| Carbon, C | ≤0.08% |
| Hydrogen, H | ≤0.0125% |
| Iron, Fe | ≤0.25% |
| Oxygen, O | ≤0.13% |
| Aluminum, Al | 5.5-6.5% |
| Vanadium, V | 3.5-4.5% |
| Residual elements, each | ≤0.10% |
| Residual elements, total | ≤0.40% |
| Titanium, Ti | Balance |
Technical references: ASTM F136 official scope and producer data for Ti-6Al-4V ELI / UNS R56401.
- Aluminum and vanadium: Al is 5.5-6.5% and V is 3.5-4.5%, together producing a heat-treatable alpha-beta microstructure. Chemical homogeneity, melting and thermomechanical processing affect microstructure and final properties.
- Oxygen, iron and interstitials: The ELI grade uses lower O, Fe, C, N and H limits to improve toughness and fatigue-crack-growth behavior. Excess levels may increase hardness, reduce ductility or create hydrogen-embrittlement risk.
- Residual elements: Each and total limits must be controlled. The material report must correspond to the heat; testing only Al and V does not satisfy the complete chemistry requirement.
- Titanium content: The specification states Titanium: Balance. A nominal grade or medical-grade claim does not replace heat-specific analysis, the material report and contract testing.
Mechanical Properties
ASTM F136 specifies room-temperature tensile properties for annealed wrought Ti-6Al-4V ELI. Bar acceptance must follow the applicable size, sampling direction, specimen form, heat-treatment condition and official table.
| Property | ASTM F136 annealed reference | Note |
| Ultimate tensile strength | ≥860 MPa | Specified minimum |
| 0.2% yield strength | ≥795 MPa | Specified minimum |
| Elongation | ≥10% | Typically in 4D; official requirement governs |
| Reduction of area | ≥25% | Where applicable to bar/specimen |
ASTM F136 Ti-6Al-4V ELI Annealed Bar Reference Requirements
| Property | Ti-6Al-4V ELI annealed reference |
| Ultimate tensile strength | Minimum 860 MPa |
| 0.2% yield strength | Minimum 795 MPa |
| Elongation | Minimum 10% |
| Elastic modulus | Typical approx. 105-116 GPa |
Important: Mechanical properties must be applied with bar size, sampling location and direction, specimen form, heat-treatment condition and the official table. Generic web data cannot replace contract acceptance, and ASTM F136 raw-material compliance alone does not approve a finished implant.
HTN Supply and Quality Documentation
HTN organizes ASTM F136 Ti-6Al-4V ELI (Grade 23) medical titanium alloy bar supply to customer purchase requirements. Material is produced by qualified titanium-mill resources. Original mill reports, heat traceability, chemistry and mechanical records can be supplied as agreed. HTN reviews edition, heat number, diameter, tolerance, condition, surface, straightness and packaging, and can arrange independent retesting, ultrasonic testing, microstructure examination, cutting, clean packaging and third-party inspection.
Typical Applications
- machining stock for hip, knee, shoulder and other joint-replacement system components;
- machining stock for orthopedic trauma plates, screws, intramedullary nails and spinal implant components;
- dental implants, abutments, restorative components and precision connectors;
- cranio-maxillofacial fixation devices, surgical clips and other high-strength implant components;
- medical-device parts requiring high specific strength, good damage tolerance and corrosion resistance;
- precision round, ground and near-net-size bar made to customer drawings;
- medical-device research, prototypes and custom implant material;
- international projects when ISO 5832-3, regulatory and customer supplementary requirements are also met.
Application boundary: ASTM F136 Ti-6Al-4V ELI bar is raw material for surgical implant applications, not an approved finished implant. The final device must separately meet applicable regulations, design validation, fatigue evaluation, biological evaluation, cleaning, sterilization and traceability requirements.
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Fabrication and Machining Characteristics
Hot Processing, Finishing and Dimensional Control
Ti-6Al-4V ELI bar is commonly produced by qualified melting, forging or rolling, annealing, straightening, and turning, peeling or centerless grinding. Machining should use rigid setups, sharp tools, low cutting speeds, steady feeds and copious non-chlorinated coolant to avoid localized heat, galling, work hardening, burns and residual tensile stress. Titanium chips are combustible and require dedicated fire and housekeeping controls.
Cold working and forming
The alloy can be cold drawn or formed to a limited extent, but room-temperature formability is lower than unalloyed titanium and springback is significant. Warm or hot forming reduces flow stress. The actual window must be qualified for diameter, microstructure, direction, surface condition and accumulated strain, with intermediate annealing where needed.
Annealing and heat treatment
Common conditions include mill annealed, recrystallization annealed or another contract-qualified condition after forging or rolling. Control temperature, soak, cooling and atmosphere to avoid grain coarsening, excessive beta transformation, alpha case and hydrogen pickup. Any special heat treatment selected for device design requires separate validation.
Welding and joining
Qualified GTAW/TIG, laser, electron-beam, resistance or diffusion joining may be used. Clean thoroughly, use compatible filler where applicable and fully shield hot metal. Device welds require validation of microstructure, strength, fatigue, corrosion resistance and cleanliness.
Typical Physical Properties
The following are typical values for annealed Ti-6Al-4V ELI near room temperature. Unless explicitly required by the standard or contract, they are not mandatory ASTM F136 lot-acceptance values.
| Physical property | reference value |
| Density | Approx. 4.43 g/cm³ |
| Elastic modulus at room temperature | Approx. 105-116 GPa |
| Thermal conductivity at room temperature | Approx. 6.7 W/(m·K) |
| Mean CTE, 20-100°C | Approx. 8.6×10⁻⁶/K |
| Solidus/liquidus reference | Approx. 1604-1660°C |
| Poisson’s ratio | Typically approx. 0.34 |
| Crystal structure at room temperature | Alpha + beta |
| Magnetism | Essentially non-magnetic |
| Strengthening mechanism | Solid solution, microstructure control and optional heat treatment |
| Specific heat at room temperature | Typically approx. 526 J/(kg·K) |
Physical-property reference: Producer data for Ti-6Al-4V ELI / UNS R56401. Values vary with temperature, microstructure, orientation, cold work and heat treatment.
Corrosion Resistance
Ti-6Al-4V ELI develops a spontaneous, renewable TiO2 passive film and generally resists saline, body fluids and many aqueous chlorides. Actual device performance also depends on roughness, inclusions or residue, micromotion, fretting, crevices, dissimilar metals, electrochemical conditions and cleaning or sterilization residue.
Environments in Which Grade 23 Generally Performs Well
- Saline and many simulated-body-fluid environments;
- humid air and high-purity water;
- neutral chloride solutions;
- many oxidizing environments;
- properly controlled cleaning and passivation processes;
- many medical-device sterilization processes after device validation;
- long-term tissue contact without fretting;
- validated orthopedic, spinal and dental implant environments.
Environments Requiring Careful Evaluation
- Fluoride cleaners, hydrofluoric acid or high-fluoride oral conditions;
- local acidification in oxygen-starved crevices;
- combined fretting, wear and corrosion;
- galvanic coupling with unsuitable dissimilar metals;
- cathodic hydrogen charging or improper electrochemical treatment;
- strong reducing acids;
- hot concentrated salts or unusual disinfection chemicals;
- areas containing particles, residues or surface damage;
- new uses lacking device-level corrosion and biological validation.
Engineering caution: Biocompatibility, fatigue and body-fluid corrosion performance are not determined by grade alone. Bar cleanliness, microstructure, roughness, residual stress, machining defects, micromotion, wear, crevices, dissimilar metals, fluoride exposure and sterilization residue can affect the final device.
Typical Production Process for ASTM F136 Ti-6Al-4V ELI Titanium Bar
- Raw-material selection and charge preparation: Use qualified titanium raw material, aluminum-vanadium master alloy and strictly controlled clean revert, closely controlling O, Fe, C, N, H and residual elements.
- Electrode preparation: Homogenize, compact and weld consumable electrodes while avoiding high-density inclusions, low-density inclusions, oil, moisture and foreign contamination.
- Melting and ingot production: Use a qualified vacuum-melting route meeting ASTM F136 and purchase requirements, controlling chemistry uniformity, inclusions and ingot quality. Melt count and special raw-material restrictions are governed by the standard and order.
- Ingot conditioning and breakdown: Crop unsuitable ends, remove surface defects, and forge or roll sufficiently to break down the cast structure.
- Hot processing to bar: Forge or roll in a controlled alpha-beta range or other qualified window, managing grain size, phase distribution, texture, dimensions, oxidation and surface quality.
- Annealing and surface conditioning: Apply a qualified anneal, remove scale and alpha case, prevent hydrogen pickup and iron contamination, and obtain ordered microstructure and properties.
- Straightening and finishing: Turn, peel, centerless grind or polish to the ordered diameter, tolerance, straightness, roughness and machining allowance.
- Cleaning: Use validated mechanical or chemical cleaning to prevent oil, abrasive, iron, chlorinated-cleaner and pickling residue. Final implant cleaning remains the device manufacturer responsibility.
- Inspection: Verify chemistry, tensile properties, dimensions, surface and identification by heat or lot. Microstructure, ultrasonic testing, grain size, macrostructure or other supplementary inspections shall follow the standard and order.
- Identification, packaging and traceability: Maintain one-to-one correspondence among heat, lot, bar and report and use clean protective packaging to prevent scratches, mix-ups and cross-contamination.
Manufacturing and inspection note: ASTM F136 specifies material requirements, but diameter and tolerance, supplementary melting requirements, ultrasonic class, microstructure, grain size, ground surface, machining allowance, clean packaging, EN 10204 3.1 documentation and third-party inspection must be confirmed in the purchase order.
