Stellite 21
Stellite® 21 (UNS R30021) breaks the family pattern: carbon is capped at 0.35% rather than run at 1-2%, and molybdenum 4.5-6.0% replaces tungsten as the strengthener. Far less carbide means it is tougher rather than harder, which is what impact and cavitation service needs.
Key Properties
- Carbon 0.35% maximum — against 0.9-1.4% on Stellite 6 and 1.4-2.0% on Stellite 12. That is the defining difference.
- Molybdenum 4.5-6.0% in place of tungsten, strengthening the matrix rather than forming coarse carbides.
- Nickel to 3.0% with chromium 26-29% on a cobalt balance.
- Tough, not hard. It is the grade for impact, thermal shock and cavitation, where the high-carbon grades chip.
Applications
- Hot-work and forging dies
- Valve components subject to impact
- Pump and turbine parts in cavitation service
- Surgical implants and prosthetics
Available Forms
Equivalent Grades & Standards
| Property | Value |
|---|---|
| UNS number | R30021 |
| Density | 8.33 g/cm3 |
| Melting range | 1295-1435 °C |
Identifiers and physical constants for Stellite 21. A dash means no such designation is published for this grade.
Aurico Alloys LLP supplies Stellite 21 across the forms above with material test certificates (EN 10204 3.1) and export-ready packaging from Mumbai, India. Chemistry and mechanical data for each product form are on the form pages linked above. Contact us for stock availability and pricing.