ASTM F562 / UNS R30035 – Wrought Cobalt-Nickel-Chromium-Molybdenum Alloy for Surgical Implants
ASTM F562 specifies the requirements for wrought 35cobalt-35nickel-20chromium-10molybdenum alloy (UNS R30035) in bar and wire forms used in the manufacture of surgical implants. This cobalt-based superalloy achieves its exceptional mechanical properties through a combination of work strengthening and aging, delivering ultra-high strength (up to 300 ksi), outstanding corrosion resistance, excellent ductility, and superior fatigue life. It is the material of choice for high-strength implantable devices requiring long-term reliability in physiological environments.
1. Product Specifications & Physical Data
UNS R30035 is available in bar and wire forms for surgical implant manufacturing. The alloy is supplied in various conditions—annealed, cold-worked, or cold-worked and aged—to achieve the required combination of strength and ductility.
Available Forms: Bar, wire, and custom components .
Specifications: ASTM F562, ISO 5832-6, UNS R30035, AMS 5844/5845 .
| Chemical Composition (Weight %) | UNS R30035 Specification |
|---|---|
| Cobalt (Co) | Balance |
| Nickel (Ni) | 33.0 - 37.0 |
| Chromium (Cr) | 19.0 - 21.0 |
| Molybdenum (Mo) | 9.0 - 10.5 |
| Iron (Fe) | 1.0 max. |
| Titanium (Ti) | 1.0 max. |
| Manganese (Mn) | 0.15 max. |
| Silicon (Si) | 0.15 max. |
| Carbon (C) | 0.025 max. |
| Phosphorus (P) | 0.015 max. |
| Sulfur (S) | 0.010 max. |
*Sources: ASTM F562 , ISO 5832-6 .*
| Physical Properties | Metric | Imperial |
|---|---|---|
| Density | 8.43 g/cm³ | 0.304 lb/in³ |
| Melting Range | 1440°C | 2625°F |
| Modulus of Elasticity | 230 - 234 GPa | 33.4 - 34.0 × 10⁶ psi |
| Electrical Resistivity | 0.86 µΩ·m | 0.86 µΩ·m |
| Magnetic Permeability | < 1.01 | < 1.01 |
Sources: ASTM F562 , Carpenter .
| Mechanical Properties (Minimum) | Annealed | Cold-Worked | Cold-Worked + Aged |
|---|---|---|---|
| Tensile Strength | 896 MPa (130 ksi) | 1310 MPa (190 ksi) | 1790 MPa (260 ksi) |
| Yield Strength (0.2% offset) | 414 MPa (60 ksi) | 965 MPa (140 ksi) | 1380 MPa (200 ksi) |
| Elongation | 45% | 12% | 8% |
| Reduction of Area | 45% | 35% | 30% |
| Hardness | 25 HRC max. | 38-45 HRC | 45-52 HRC |
*Sources: ASTM F562 , ISO 5832-6 .*
2. Operating Conditions & Selection Criteria
UNS R30035 is specified for surgical implant applications requiring the highest combination of strength, corrosion resistance, and fatigue life.
Biocompatibility: Approved per ASTM F562 and ISO 5832-6 for surgical implants; excellent tissue compatibility and resistance to corrosion in physiological environments .
Strengthening Mechanism: Multiphaser reinforced by cold work (45-50% reduction) followed by aging (650-700°C); achieves tensile strengths exceeding 1790 MPa (260 ksi) .
Corrosion Resistance: Exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride-containing body fluids .
Fatigue Strength: Outstanding high-cycle fatigue life essential for load-bearing implants and cardiovascular devices .
Non-Magnetic: Low magnetic permeability (< 1.01) ensures MRI compatibility and patient safety .
Service Environment: Suitable for long-term implantation in physiological environments; excellent performance under cyclic loading .
3. Fabrication & Material Comparison
Annealing: 1066-1177°C (1950-2150°F), rapid cool (water quench); produces soft, formable condition .
Cold Working: 45-50% cold reduction activates age-hardening response; material supplied in cold-worked or cold-worked and aged conditions .
Aging: 650-700°C (1200-1290°F) × 4-8 hours, air cool; develops full strength after cold work .
Machining: Difficult due to high strength and work-hardening rate; requires rigid setups, slow speeds, positive feeds, and ample coolant .
Welding: Limited weldability; components typically mechanically fastened rather than welded .
Surface Finishing: Electropolishing or mechanical polishing recommended for implant surfaces to enhance corrosion resistance and fatigue life .
| Material Comparison | UNS R30035 | ASTM F75 (CoCrMo) | ASTM F136 (Ti-6Al-4V) | ASTM F138 (316L) |
|---|---|---|---|---|
| Tensile Strength (max.) | 260 ksi (aged) | 95 ksi | 125 ksi | 80 ksi |
| Yield Strength (max.) | 200 ksi (aged) | 65 ksi | 115 ksi | 28 ksi |
| Modulus of Elasticity | 230 GPa | 210 GPa | 110 GPa | 193 GPa |
| Fatigue Strength | Excellent | Good | Good | Moderate |
| MRI Compatibility | Excellent | Moderate | Excellent | Excellent |
| Primary Use | High-strength implants | Joint replacements | Orthopedic implants | General implants |
Applications
Orthopedic Implants: Hip stems, femoral components, knee replacements, spinal rods, bone screws
Cardiovascular: Stents, heart valve frames, pacemaker leads, vena cava filters
Surgical Instruments: Forceps, retractors, scissors, cutting tools requiring high strength
Dental: Implant abutments, orthodontic wires, prosthetic components
Cranial & Maxillofacial: Plates, mesh, screws for facial reconstruction
Spinal Devices: Rods, cages, screws, interbody fusion devices
Contact ZYTC Alloy for certified ASTM F562 UNS R30035 surgical implant bar and wire with complete traceability, EN 10204 3.1/3.2 certificates, and competitive pricing. Available in annealed, cold-worked, and aged conditions to meet your medical device manufacturing requirements.
📧 Email: daisy@zytcsteel.com
🌐 Website: https://www.zytcalloys.com/products/astm-f562-/-uns-r30035-surgical-implant-alloy-bar.html
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