ASTM F67 Grade 3 Unalloyed Titanium Wire
- Standard: ASTM F67
- Grade: Grade 3 (Unalloyed Titanium)
- UNS: R50550
- Supply form: Coil or straight-length wire
- Condition: Annealed or as ordered
- Diameter Range: Ø0.03–Ø7.0 mm
Customizable sizes are available, while specific product parameters should be confirmed per the applicable standard edition and order.
Product Overview
ASTM F67 Grade 3 unalloyed titanium wire is wrought commercially pure titanium wire used to manufacture surgical implants, UNS R50550. Among the four unalloyed grades in ASTM F67, Grade 3 provides relatively high strength while retaining useful ductility, corrosion resistance and wire-processing capability. Its performance is achieved principally through a higher but controlled oxygen level together with limits on iron, nitrogen, carbon and hydrogen.
The material offers good biocompatibility, resistance to physiological corrosion and higher strength for medical wire requiring greater strength than Grade 2 with moderate coiling or forming complexity. ASTM F67 compliance applies to the wire raw material; it does not mean a finished implant has completed design verification, biological evaluation, cleaning, sterilization or regulatory approval.
| Specification | Details |
| Industrial Standard | ASTM F67 |
| Grades | Gr3 |
| Diameter Range | Ø0.03–Ø7.0 mm |
| Typical Diameters | Ø0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 7.0 mm |
| Supply Form | Coil / Spool or straightened and cut wire |
Medical-use boundary: ASTM F67-compliant titanium wire is medical-device raw material, not an approved finished implant. The device manufacturer remains responsible for design, manufacturing, cleaning, sterilization, biological evaluation, risk management and regulatory compliance.
Main Characteristics
- Higher strength: Annealed Grade 3 is stronger than Grades 1 and 2 and is suited to unalloyed titanium wire parts requiring greater load capacity and resistance to permanent deformation.
- Controlled unalloyed chemistry: No nominal alloying addition is made; O, Fe, N, C and H are controlled to provide higher strength while retaining useful ductility, toughness and drawing consistency.
- Good biocompatibility: A stable TiO2 passive film helps limit ion release in physiological environments. The finished device still requires applicable biological evaluation.
- Good corrosion resistance: Performance is generally excellent in saline, body fluids and many chlorides, but crevices, fretting corrosion, dissimilar-metal coupling and fluoride exposure require device-level evaluation.
- Good weldability: Qualified inert-gas, laser or resistance welding may be used; heat input and shielding of fine wire must be tightly controlled to prevent O, N, H and C contamination.
- Lower forming margin than lower grades: Grade 3 has higher strength, but ductility, fine-wire drawing and complex cold-forming margins are generally lower than Grades 1 and 2. Load-bearing implants still require design verification using actual load, fatigue, diameter, surface condition and service-life requirements.
Chemical Composition
The following limits apply to ASTM F67 Grade 3. Values are mass percentages. Formal acceptance is governed by the contract edition and producer certified report.
| Element | ASTM F67 Grade 3 requirement |
| Nitrogen, N | ≤0.05% |
| Carbon, C | ≤0.08% |
| Hydrogen, H | ≤0.015% |
| Iron, Fe | ≤0.30% |
| Oxygen, O | ≤0.35% |
| Residual elements, each | ≤0.10% |
| Residual elements, total | ≤0.40% |
| Titanium, Ti | Balance |
- Technical references: ASTM F67 official scope and producer data for Grade 3 / UNS R50550.
- Oxygen, nitrogen and iron: Oxygen is the principal interstitial strengthener used to obtain Grade 3 strength; nitrogen and iron also contribute. Grade 3 permits higher oxygen and nitrogen limits than Grade 2, increasing strength while reducing ductility, fine-wire drawability and complex-forming capability.
- Nitrogen, carbon and hydrogen: These elements require strict control. Excess content raises hardness and reduces ductility; hydrogen may promote hydrides and embrittlement.
- Residual elements: Each and total limits must be controlled. Testing only the principal impurities does not satisfy the full chemistry requirement.
- Titanium content: The specification states Titanium: Balance. A nominal purity claim does not replace heat-specific chemical analysis and the material report.
Mechanical Properties
ASTM F67 specifies room-temperature tensile properties for Grade 3 wrought products. Wire specimens are generally tested along the wire axis; formal acceptance must follow the applicable diameter, specimen form, condition and official standard table.
| Property | ASTM F67 Grade 3 annealed reference | Note |
| Ultimate tensile strength | ≥450 MPa | Official applicable product table governs |
| 0.2% yield strength | 380-550 MPa | A specified range, not one minimum |
| Elongation | ≥18% | Subject to size and specimen conditions |
| Reduction of area | Per applicable diameter/specimen requirement | Check the official table when ordered |
ASTM F67 Grade 3 Annealed Titanium Wire Reference Requirements
| Property | Grade 3 annealed reference |
| Ultimate tensile strength | Minimum 450 MPa |
| 0.2% yield strength | 380-550 MPa |
| Elongation | Minimum 18% |
| Elastic modulus | Typical approx. 105 GPa |
Important: Mechanical properties must be applied with Grade 3 wire diameter, specimen form, condition and the official table. Generic website data cannot replace contract acceptance, and ASTM F67 raw-material compliance alone does not qualify a finished implant.
HTN Supply and Quality Documentation
HTN organizes ASTM F67 Grade 3 unalloyed titanium wire 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, coil or straight-length form, surface, straightness and packaging, and can arrange independent retesting, straightening, cut-to-length service, clean packaging and third-party inspection.
Typical Applications
- Raw material for orthopedic or trauma-fixation cerclage wire, ligature wire and related parts after device-level validation;
- higher-strength fine wire, mesh or formed-component stock for cranio-maxillofacial, dental and restorative devices;
- surgical-instrument parts requiring relatively high strength, good corrosion resistance and moderate coiling capability;
- raw material for implant meshes, support structures, small connecting parts and structural unalloyed titanium wire components;
- medical locating wire, connecting wire, resilient elements and precision formed parts;
- precision titanium wire drawn, straightened, cut or processed to customer drawings;
- research, prototype and custom medical-device material;
- international projects when ISO 5832-2, regulatory and customer requirements are also met.
Application boundary: ASTM F67 Grade 3 titanium wire is raw material for surgical implant manufacture, not an approved finished implant. The final device must separately meet applicable regulations, design validation, biological evaluation, cleaning, sterilization and traceability requirements.
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Fabrication and Machining Characteristics
Drawing, Straightening and Dimensional Control
Grade 3 wire is typically produced by multiple drawing passes from wire rod. Die condition, area reduction per pass, lubrication, drawing speed and intermediate annealing must be tightly controlled to limit scoring, laps, localized necking, out-of-roundness and residual stress. Because Grade 3 has higher strength, fine-wire drawing generally requires more conservative reductions and a carefully validated intermediate-annealing schedule.
Cold working
Grade 3 may be bent, coiled, woven, flattened or end formed under controlled conditions, but its forming margin is lower than Grades 1 and 2. Larger bend radii and intermediate annealing may be required. Actual limits depend on diameter, grain size, surface condition and cold-work level.
Annealing and heat treatment
Annealing restores ductility after drawing, lowers residual stress and stabilizes equiaxed alpha microstructure. Unalloyed titanium is not conventionally precipitation hardened; Grade 3 obtains its higher strength mainly from controlled interstitial elements, and cold work can further increase strength. Qualified atmospheres are required to prevent oxidation, alpha case and hydrogen pickup.
Welding and joining
Qualified GTAW/TIG, laser or resistance welding may be used. Clean thoroughly before welding and fully shield the pool, root and hot heat-affected zone. Fine-wire joints require device-level strength, fatigue, corrosion and cleanliness validation.
Typical Physical Properties
The following are typical Grade 3 values near room temperature; unless explicitly specified, they are not mandatory lot-acceptance values of ASTM F67 .
| Physical property | Reference value |
| Density | Approx. 4.51 g/cm³ |
| Elastic modulus at room temperature | Approx. 105 GPa |
| Thermal conductivity at 21°C | Approx. 16 W/(m·K) |
| Mean CTE, 20-100°C | Approx. 8.6×10⁻⁶/K |
| Melting temperature reference | Approx. 1670°C |
| Poisson’s ratio | Typically approx. 0.34 |
| Crystal structure at room temperature | HCP alpha titanium |
| Magnetism | Essentially non-magnetic |
| Strengthening mechanism | Mainly cold work; not conventionally age hardenable |
| Specific heat at room temperature | Typically approx. 520 J/(kg·K) |
Physical-property reference: Producer data for Grade 3 / UNS R50550. Values vary with temperature, microstructure, orientation, cold work and heat treatment.
Corrosion Resistance
Grade 3 develops a spontaneous, renewable TiO2 passive film and generally resists saline, body fluids and many chloride environments. Actual device performance also depends on surface treatment, crevices, micromotion, dissimilar metals, electrochemical conditions and sterilization or cleaning residues.
Environments in Which Grade 3 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 dental and orthopedic device 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 and body-fluid corrosion performance are not determined by grade alone. Roughness, cleanliness, micromotion, wear, crevices, dissimilar metals, fluoride exposure and sterilization residues can affect the final device.
Typical Industry Manufacturing Route for ASTM F67 Grade 3 Titanium Wire
- Raw-material selection and charge preparation: Select qualified high-purity sponge and strictly controlled clean revert, closely controlling O, Fe, N, C, H and residuals.
- Electrode preparation: Homogenize, compact and weld a consumable electrode while avoiding iron particles, oil, moisture and foreign contamination.
- Vacuum melting and ingot production: VAR or another qualified vacuum route is commonly used. ASTM F67 specifies finished-material requirements; special melt count or raw-material restrictions must be stated in the order.
- Ingot conditioning and breakdown: Crop unsuitable ends, remove surface defects, and forge or roll to break down the cast structure and produce billet suitable for rod rolling.
- Wire-rod rolling: Roll the billet to coil or wire rod under controlled temperature, managing structure uniformity, dimensions, scale and surface defects.
- Surface conditioning and preliminary annealing: Use validated pickling, mechanical peeling or another suitable method to remove scale and alpha case while controlling hydrogen pickup and iron contamination.
- Multi-pass drawing: Draw progressively through qualified dies to the target diameter. Apply intermediate annealing according to cold work and control diameter tolerance, out-of-roundness, surface quality and mechanical properties.
- Final annealing, straightening and cleaning: Apply final annealing or stress relief as ordered. Supply as coil wire or straightened cut lengths, and use validated cleaning to remove lubricant, abrasive, iron and pickling residues.
- Inspection: Verify chemistry, tensile properties, diameter, out-of-roundness, surface and appearance; check length and straightness for straight wire. Special microstructure, grain size, roughness or nondestructive testing must be ordered when required.
- Identification, packaging and traceability: Maintain heat, lot, coil/straight wire and report correspondence. Use clean spools, coils or protective tubes to prevent tangling, kinking, scratches and cross-contamination.
Manufacturing and inspection note: ASTM F67 specifies material requirements, but special melt count, microstructure, grain size, tight diameter tolerance, out-of-roundness, straightness, surface roughness, clean packaging, EN 10204 3.1 documentation and third-party inspection must be confirmed in the purchase order.
