Wear Resistant CoCr · Stellite Hardfacing
Cobalt-Chrome Alloy Stellite 21
Cobalt-Chrome Alloy Stellite 21 is a wear resistant cocr cobalt-chrome alloy — tougher hardfacing cobalt. Typical values: 700 MPa yield, 8.36 g/cm³, rated to 700 °C. Available for CNC machining at FabDigit.
Properties
Typical room-temperature values in the As Cast condition. Metric first, imperial in gray. The bars show where Stellite 21 sits against the other 5 cobalt-chrome alloy grades in the catalog.
Datasheet
| Yield strength | 700 MPa102 ksi |
|---|---|
| Tensile strength | 1,000 MPa145 ksi |
| Hardness | 38 HRC≈ 353 HB |
| Density | 8.36 g/cm³0.302 lb/in³ |
| Specific strength (yield ÷ density) | 84 |
| Min service temp | -200 °C-328 °F |
| Max service temp | 700 °C1,292 °F |
| Electrical conductivity | 1.7 % IACS1 MS/m |
| Machinability | Poor20 / 100 |
| Weldability | Very good75 / 100 |
| Formability | Not recommended5 / 100 |
| ISO 513 machining group | S |
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Against other cobalt-chrome alloy grades
Strength versus weight in the cobalt-chrome alloy family
Yield strength against density for every cobalt-chrome alloy grade FabDigit runs. Stellite 21 is highlighted; hover a dot for its name, or open the interactive family chart.
Manufacturability
The process limits FabDigit's quote engine applies to Stellite 21. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Poor20 / 100 |
|---|---|
| ISO material group | S.2 |
| Cutting speed (rough / finish) | 30 / 40 m/min |
| Minimum wall | 2 mm |
| Minimum internal radius | 2.5 mm |
| Drill depth limit | 2.5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Conditions and tempers
How Stellite 21 is supplied and what each state is for. The default is what FabDigit quotes unless your drawing says otherwise.
| Condition | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
As CastDefault Finish State | Rough surface acceptable — hidden or machined-over faces | — | — | — | — |
Hot Worked Cold Work | Hot-worked stock — general machining, moderate loads | — | — | — | — |
Heat treatment and post-processing
Operations FabDigit's suppliers routinely run on Stellite 21, ranked by how often they make sense for this grade.
Heat treatment
| Hot Isostatic Press (HIP) | Eliminate porosity in cast / 3DP parts |
|---|---|
| Solution Anneal | Dissolve carbides; reset austenite (stainless) |
Post-processing
| Manual Deburr | Deburrstandard |
|---|---|
| Edge Break (0.5mm) | Deburr |
| Electropolish | Polish |
| CMM Inspection | Inspection |
| FAI Report | Inspection |
| Individual Bag | Packaging |
Surface finishes for Stellite 21
Coatings and treatments compatible with cobalt-chrome alloy on the processes Stellite 21 runs on. Pick them in the quote configurator or call them out on the drawing.
Passivation
- Electropolishing
- Passivation (Stainless Steel)
Marking / Decoration
- Chemical Etching
- Dot Peen Marking
- Electro-chemical Etching
- Ink Stamping
- Laser Marking
- Mechanical Engraving
- Steel Stamping
- Vibro Engraving / Scribing
Equivalent designations
Standards and trade names that resolve to Cobalt-Chrome Alloy Stellite 21 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R30021
- Trade names
- CoCrMo Stellite
Stock forms
Raw-material forms FabDigit sources Stellite 21 in.
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.