CoCrMo F75 vs Stellite 21: 62% composition overlap. Moderate differences, generally not direct substitutes.
CoCrMo F75 vs Stellite 21
Side-by-side chemical composition and mechanical property comparison.
Overview
CoCrMo F75
R30075
Cobalt-28Chromium-6Molybdenum investment casting alloy for surgical implants. The standard material for orthopedic hip and knee joint replacements since the 1970s. Excellent biocompatibility, wear resistance (metal-on-metal bearings), and corrosion resistance from passive Cr oxide layer. Also used in dental prosthetics (crowns, bridges, denture frameworks). Typically produced by lost-wax (investment) casting, often followed by HIP to eliminate porosity. ISO designation: ISO 5832-4.
Stellite 21
R30021
Low-carbon cobalt-chromium-molybdenum alloy optimized for cavitation, galling, and corrosion resistance rather than abrasive wear. CoCrMo matrix without tungsten — Mo replaces W for superior corrosion resistance in reducing environments. Lower hardness (25-35 HRC) than Stellite 6 but better ductility and thermal/mechanical shock resistance. Used for valve seats in corrosive service, pump components in chemical processing, hot gas path components, and nuclear valve hardfacing. Also used as dental/orthopedic implant hardfacing.
| CoCrMo F75 | Stellite 21 | |
|---|---|---|
| Material Number | R30075 | R30021 |
| Category | cobalt | cobalt |
| Standard | ASTM F75 | AMS 5895 |
Chemical composition (wt%)
| Element | CoCrMo F75 | Stellite 21 | Overlap |
|---|---|---|---|
| C | ≤ 0.35% | ≤ 0.35% | OK |
| Si | ≤ 1% | ≤ 1.5% | OK |
| Mn | ≤ 1% | ≤ 1% | OK |
| Cr | 27–30% | 26–29% | Partial |
Mechanical properties
| Property | CoCrMo F75 | Stellite 21 | Unit |
|---|---|---|---|
| tensile_strength | ≥ 655 | — | MPa |
| yield_strength | ≥ 450 | — | MPa |
| elongation | ≥ 8 | — | % |
Compatibility Assessment
CoCrMo F75 and Stellite 21 have moderate differences (62% overlap). They are generally not direct substitutes. Consider the specific requirements of your application.
Automated assessment based on composition analysis
Frequently Asked Questions
Is CoCrMo F75 the same as Stellite 21?
CoCrMo F75 and Stellite 21 have a 62% composition overlap. They are generally not directly interchangeable.
Can I replace CoCrMo F75 with Stellite 21?
Generally not recommended. The compositions differ significantly (62% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between CoCrMo F75 and Stellite 21?
The main differences are in the following elements: Cr, Mo. CoCrMo F75 is a cobalt grade, while Stellite 21 is a cobalt grade.
View full data for each material:
Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.