Cobalt-Chrome Alloy F75 · print state
Cobalt-Chrome Alloy F75-HIP
Properties of the HIP condition, compared with the other F75 tempers.
Pick for load-bearing implants and critical AM parts: closes porosity and lack-of-fusion defects, giving the best ductility, toughness and fatigue life.
What is F75-HIP?
F75-HIP is F75 in the HIP condition — pick for load-bearing implants and critical AM parts: closes porosity and lack-of-fusion defects, giving the best ductility, toughness and fatigue life. F75-HIP has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 70% of cobalt-chrome alloy grades. Elongation at break is 20% and the elastic modulus is 225 GPa (32.6 Msi). F75-HIP has a density of 8.32 g/cm³ (0.301 lb/in³), lighter than 66% of cobalt-chrome alloy grades. It melts at 1,330°C (2,426 °F). As Cast is the default condition FabDigit quotes; HIP is available on request or by drawing note.
Advantages
- Good corrosion resistance — 90/100, better than 93% of cobalt-chrome alloy grades
- Tough — resists crack growth — 80 MPa·√m (72.8 ksi·√in), better than 88% of cobalt-chrome alloy grades
- Ductile — tolerates forming and impact — 20%, better than 79% of cobalt-chrome alloy grades
F75-HIP properties
Typical room-temperature values for F75-HIP — 13 properties are specific to this condition; the rest are grade-level values shared by every F75 temper. Each bar shows where the value sits among the cobalt-chrome alloy grades in FabDigit's library — further right is higher.
Physical3
F75-HIP has a density of 8.32 g/cm³ (0.301 lb/in³), lighter than 66% of cobalt-chrome alloy grades. It melts at 1,330°C (2,426 °F).
Mechanical16
F75-HIP has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 70% of cobalt-chrome alloy grades. Elongation at break is 20% and the elastic modulus is 225 GPa (32.6 Msi).
Thermal6
F75-HIP is rated for continuous service to 600°C (1,112 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 53% of cobalt-chrome alloy grades. Thermal expansion is 13 µm/m·K (7.22 µin/in·°F).
Electrical3
F75-HIP conducts electricity at 1.9 % IACS, worse than 54% of cobalt-chrome alloy grades.
Chemical & Environmental3
Corrosion resistance is excellent (90/100), better than 93% of cobalt-chrome alloy grades.
Sustainability4
Producing a kilogram of F75-HIP takes about 150 MJ of energy and emits 11 kg of CO₂ — less than 60% of cobalt-chrome alloy grades. Typical recycled content is 25%.
Manufacturability8
F75-HIP's machinability is not recommended (13/100, better than 69% of cobalt-chrome alloy grades); weldability poor (25/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other F75 tempers and conditions
F75 is also supplied in 6 other conditions. The full side-by-side table is on the F75 overview.
- As CastDefaultDefault condition for investment-cast implant and dental components; meets ASTM F75 minimums with coarse dendritic structure and interdendritic carbides.510 MPa yield · 30 HRC
- As PrintedAs-built laser powder-bed condition: very fine cellular structure gives the highest strength and hardness of any F75 form, but with residual stress and anisotropy.900 MPa yield · 40 HRC
- pressure_sinteredPowder-metallurgy Co-28Cr-6Mo consolidated by uniaxial hot pressing / pressure-assisted sintering to near-full density, giving a fine equiaxed grain structure with markedly higher strength and ductility than the cast alloy.840 MPa yield · 36 HRC
- Stress RelievedStandard post-print treatment for laser-melted CoCrMo: removes residual stress and prevents distortion while keeping most as-printed strength.820 MPa yield · 37 HRC
- HIPPick for load-bearing implants and critical AM parts: closes porosity and lack-of-fusion defects, giving the best ductility, toughness and fatigue life.650 MPa yield · 32 HRC
- heat_treated_castInvestment-cast Co-28Cr-6Mo (R30075) given a post-cast homogenizing/solution heat treatment that dissolves interdendritic carbides and raises ductility over the as-cast state while keeping the coarse cast grain structure.560 MPa yield · 31 HRC
- Solution AnnealedChoose when carbide dissolution and higher ductility/uniformity are needed before final machining or forming of cast or AM parts.520 MPa yield · 28 HRC
Working with F75-HIP
Is F75 easy to machine?
Rigid setups, sharp positive-rake carbide or ceramic tools, low speed (15–30 m/min carbide) with heavy constant feed and flood coolant — never dwell, the alloy work-hardens instantly; grinding and EDM are common for finished implant geometry.
Can F75 be welded?
Cast high-carbon F75 is prone to hot cracking; use low-heat GTAW/laser/electron-beam with matching Co-Cr filler, preheat and post-weld solution treatment, or design to avoid welding altogether.
Can F75 be formed, bent or molded?
Not cold formable — parts are investment cast, laser powder-bed printed or milled from HIPed blanks; AM builds need supports, 750–1150 °C stress relief and optional HIP.
What surface finishes work on F75?
Sand/blast, then belt and diamond/alumina polish to a mirror bearing surface (Ra ≤ 0.02 µm); passivate or electropolish for biocompatibility; DLC/TiN PVD used for extra wear life. No anodizing.
F75 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Crpassive film former | 27 – 30 | 28.5 |
| Mosolid-solution strengthening, pitting resistance | 5 – 7 | 6 |
| Niimpurity limit (allergy control) | ≤ 0.5 | 0.2 |
| Fe | ≤ 0.75 | 0.3 |
| Clow-carbon AM powders typically ≤0.16 | ≤ 0.35 | 0.25 |
| Si | ≤ 1 | 0.6 |
| Mn | ≤ 1 | 0.6 |
| W | ≤ 0.2 | — |
| N | ≤ 0.25 | — |
| Al | ≤ 0.1 | — |
| Ti | ≤ 0.1 | — |
| B | ≤ 0.01 | — |
| P | ≤ 0.02 | — |
| S | ≤ 0.01 | — |
| Cobalance, ≈62–65 % | balance | — |
F75-HIP — frequently asked
What is F75-HIP used for?
F75-HIP is typically used for hip femoral heads and stems, knee femoral components, dental crowns and bridges, partial denture frameworks, spinal implant components and wear-resistant bearing surfaces. In short: medical implant cobalt.
What is the yield strength of F75-HIP?
F75-HIP has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 1,000 MPa (145 ksi) — stronger than 70% of cobalt-chrome alloy grades. Strength varies by condition: see the 7 listed tempers.
Is F75-HIP easy to machine?
Not especially — machinability is rated not recommended (13/100, better than 69% of cobalt-chrome alloy grades). Rigid setups, sharp positive-rake carbide or ceramic tools, low speed (15–30 m/min carbide) with heavy constant feed and flood coolant — never dwell, the alloy work-hardens instantly; grinding and EDM are common for finished implant geometry.
Can F75-HIP be welded?
Not readily — weldability is rated poor (25/100). Cast high-carbon F75 is prone to hot cracking; use low-heat GTAW/laser/electron-beam with matching Co-Cr filler, preheat and post-weld solution treatment, or design to avoid welding altogether.
What surface finishes work on F75-HIP?
Sand/blast, then belt and diamond/alumina polish to a mirror bearing surface (Ra ≤ 0.02 µm); passivate or electropolish for biocompatibility; DLC/TiN PVD used for extra wear life. No anodizing.
Can F75-HIP be formed, bent or molded?
Not cold formable — parts are investment cast, laser powder-bed printed or milled from HIPed blanks; AM builds need supports, 750–1150 °C stress relief and optional HIP.
What is the maximum service temperature of F75-HIP?
F75-HIP is rated for continuous use to about 600°C (1,112 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between F75 As Cast and F75-HIP?
As Cast is the default condition — default condition for investment-cast implant and dental components; meets ASTM F75 minimums with coarse dendritic structure and interdendritic carbides. HIP: pick for load-bearing implants and critical AM parts: closes porosity and lack-of-fusion defects, giving the best ductility, toughness and fatigue life. Yield strength is 510 MPa in As Cast versus 650 MPa in HIP.
Can FabDigit make parts in F75-HIP?
Yes — F75-HIP is available for CNC machining and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM F75 — Standard Specification for Cobalt-28 Chromium-6 Molybdenum Alloy Castings and Casting Alloy for Surgical Implants — ASTM International (2018)
- ASTM F3301 — Additive Manufacturing, Post Processing Methods, Standard Specification for Thermal Post-Processing Metal Parts — ASTM International (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Cobalt-Base Alloys) — ASM International (1990)
- EOS CobaltChrome MP1 Material Data Sheet — EOS GmbH (2022)
- Sandvik Osprey CoCrMo (ASTM F75) AM Powder Datasheet — Sandvik (2022)
- Biomaterials property compilations for Co-Cr-Mo implant alloys — Springer / Elsevier reviews (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.