ASTM F67 Gr4 Titanium Rod Description
ASTM F67 Gr4 titanium rod is a surgical implant-grade α-type commercially pure titanium rod, complying with ASTM F67 standard for medical implantation, and it is a high-strength commercial pure titanium widely applied in medical implants and high-load precision industries.
Chemical composition: Ti ≥ 99.0%, with strictly controlled trace impurities (Fe, O, C, N, H), guaranteeing stable biocompatibility and long-term service safety.
Key characteristics: Outstanding comprehensive mechanical properties among commercial pure titanium; great hardness and tensile strength, superior to Gr1 and Gr2; moderate formability and weldability; exceptional corrosion resistance against body fluids and harsh chemical media, as well as reliable structural stability under continuous high-load and low-temperature conditions.
Rod form: Available in round rods as the mainstream type, plus square rods and hexagonal rods; manufactured through hot rolling, precision forging and cold drawing processes.
Main applications: Medical field (high-load bone plates, heavy-duty bone screws, structural implant components and high-strength surgical devices); aerospace field (high-strength lightweight parts, pressure-bearing structural components and cryogenic service parts); industrial field (high-strength corrosion-resistant fittings for marine, chemical and extreme working environments).
Technical Specifications
Chemical Specification
|
Elements |
Ti(Bal.) |
O |
Fe |
C |
N |
H |
Other impurities |
|
Max. content |
≥99.0% |
≤0.40 |
≤0.50 |
≤0.08 |
≤0.05 |
≤0.015 |
≤0.40 |
Physical Specification
|
Mechanical properties |
Standard |
Physical properties |
Value |
Service performance |
Property features |
|
Tensile strength |
≥550 MPa |
Density |
4.51 g/cm³ |
Weldability |
Excellent |
|
Yield strength |
≥485 MPa |
Melt point |
Around 1668 ℃ |
Machinability |
Excellent |
|
Elongation |
≥15% |
– |
– |
Corrosion resistance |
Good |
|
Hardness |
160-220 HV | – |
– |
Low temperature performance |
Good |
Features & Advantages
- Highest strength among CP titanium grades: Gr4 possesses the highest tensile strength and yield strength in commercially pure titanium, ideal for high-load medical implant applications.
- Excellent structural rigidity and wear resistance: Higher hardness than Gr1 and Gr2, delivering better surface wear resistance and structural stability for long-term implanted components.
- Fully medical-grade biocompatibility: Complies with ASTM F67 surgical implant standard, non-toxic, non-allergenic and biologically inert, safe for permanent human tissue contact.
- Superior fatigue resistance under cyclic loading: Great anti-fatigue performance under repeated force, suitable for weight bearing bone fixation and dynamic orthopedic devices.
- Non magnetic & compatible with medical imaging: Non-magnetic property avoids MRI/CT image distortion, ensuring full compatibility with routine clinical examination.
- Outstanding corrosion resistance to body fluid: Dense passive oxide film provides strong resistance to saliva, blood and bodily fluid corrosion, preventing metal ion precipitation.
- Non-quenchable strengthening & stable performance: Cannot be hardened by quenching; properties are stable and consistent, avoiding structural brittleness caused by heat treatment.
- Balanced machinability and forming performance: Though stronger than Gr1/Gr2, it still maintains moderate ductility, supporting precision machining, forging and customized medical part production.
Performance Solution
Problem: Stainless steel and cobalt-chromium alloys have high density and weight, which increase the patient’s burden after orthopedic implantation, affecting mobility and rehabilitation.
Solution: Medical Grade 4 titanium is low in density and lightweight, greatly reducing the implantation weight, improving wearing comfort and postoperative recovery efficiency.
Problem: Ordinary alloys are prone to corrosion and rust when in long-term contact with human body fluids, precipitating metal ions and causing allergies, inflammation and tissue irritation.
Solution: Gr4 has extremely strong biological corrosion resistance, with a stable surface passive oxide film, resistant to corrosion from blood, body fluids and oral environments, ensuring safe and stable long-term implantation.
Problem: Pure titanium Gr1 and Gr2 have low strength, which are prone to deformation, bending and fixation failure in high-load and high-stress implantation sites.
Solution: Gr4 is the highest strength grade in the commercially pure titanium series, with tensile strength and hardness significantly superior to Gr1/Gr2, meeting the needs of high-load orthopedic bearing implants.
Problem: Gr1 and Gr2 have insufficient hardness, so the contact surfaces of instruments are prone to wear and particle shedding, resulting in short service life and being unsuitable for high-frequency stress-bearing components.
Solution: Gr4 has comprehensively improved hardness and wear resistance, with excellent wear resistance and fatigue resistance, suitable for precision surgical accessories and structural implants that bear repeated stress.
Problem: Conventional iron-based alloys are ferromagnetic, which will interfere with MRI examinations, produce image artifacts and pose potential diagnostic and therapeutic safety hazards.
Solution: Gr4 is completely non-magnetic, compatible with various imaging examinations such as MRI and CT, does not affect clinical diagnosis, and is suitable for lifelong implant consumables.
Problem: Some high-strength medical alloys have poor toughness and are prone to brittleness at low temperatures, and are likely to break and crack under sterilization low-temperature environments or traumatic stress.
Solution: Gr4 has excellent low-temperature toughness and no cold brittleness, with stable mechanical structure, and can withstand low-temperature disinfection and complex clinical working conditions.
Problem: Most traditional high-strength medical alloys can be strengthened by quenching, which is prone to internal stress after heat treatment, increasing the risk of fracture and loosening.
Solution: Gr4 is non-quenchable and cannot be strengthened by quenching, with uniform and stable material structure, no risk of embrittlement caused by heat treatment, and more reliable long-term mechanical properties of implants.
Problem: The elastic modulus of dissimilar metal implants is too high, which is prone to cause stress shielding, inducing bone resorption and implant loosening and falling off.
Solution: The elastic modulus of Gr4 is close to that of human bones, effectively reducing stress shielding, promoting osseointegration, and improving the long-term fixation effect of implants.
Application
1. High-Load Orthopedic Bearing Implants
Applied to weight-bearing bone plates, heavy-duty bone screws and joint fixation components for hip, knee and spine surgeries. Its superior strength (higher than Gr1/Gr2) solves the problem of deformation and fixation failure of low-strength materials, ensuring long-term stability under cyclic loading.
2. Long-Term Implantable Dental Structural Components
Used for high-strength dental implant abutments, customized denture frameworks and orthodontic anchor screws. The stable passive oxide film resists corrosion from oral saliva and bacteria, avoiding metal ion precipitation and gum irritation, suitable for permanent dental implantation.
3. High-Frequency Stress Surgical Instrument Parts
Manufactured into precision forceps, needle holders, minimally invasive surgical instrument tips and repeated stress-bearing accessories. Compared with Gr1/Gr2, its improved hardness and wear resistance prevent surface wear and particle shedding, extending the service life of reusable instruments.
4. MRI-Compatible Lifelong Implant Consumables
Used for permanent implant components such as cardiac vascular clips, soft tissue support brackets and cranial fixation devices. Being completely non-magnetic, it avoids MRI/CT image distortion and safety hazards, solving the interference problem of ferromagnetic materials.
5. Cryogenic Medical Device Components
Applied to core parts of cryosurgery equipment, low-temperature sterilization tools and cryopreservation auxiliary components. Its excellent low-temperature toughness (no cold brittleness) prevents brittle fracture under ultra-low temperature disinfection or cryotherapy conditions.
6. High-Strength Craniofacial Reconstruction Implants
Suitable for personalized jaw, orbital and nasal defect repair prostheses. While maintaining moderate formability, its high strength and rigidity solve the problem of insufficient support of low-strength materials, fitting the complex anatomical structure of the craniofacial region.
7. Non-Heat-Treatable Stable Implant Components
Used for high-reliability implant parts such as spinal fixation rods and trauma fixation devices. Being non-quenchable, it avoids internal stress and embrittlement caused by heat treatment, ensuring uniform material structure and long-term mechanical stability.
8. Low-Stress-Shielding Orthopedic Implants
Applied to load-bearing implants that require long-term osseointegration, such as femoral stem accessories and tibial plateau implants. Its elastic modulus close to human bone effectively reduces stress shielding, solving the problem of bone resorption and implant loosening caused by dissimilar metals.