Stellite 21
Molybdenum-bearing cobalt alloy with good toughness and corrosion resistance.
Material overview
Stellite 21 is recorded in the Cobalt-Based Alloys catalog. Molybdenum-bearing cobalt alloy with good toughness and corrosion resistance. Its recorded characteristics include Lower carbon for higher ductility, molybdenum strengthens and improves corrosion, and thermal-shock resistant. Typical applications include hot-forming and forging dies, valve plugs, and pump and chemical equipment. The dataset currently includes 11 property records covering chemical composition, mechanical properties, and physical properties. Related standards include A5.21 and A5.13; product form data covers Bar / Rod and Cast Product. The final chemistry, condition, dimensions, test requirements, and documentation package must be confirmed before order acceptance.
Key characteristics
- Lower carbon for higher ductility
- molybdenum strengthens and improves corrosion
- thermal-shock resistant
Typical applications
- hot-forming and forging dies
- valve plugs
- pump and chemical equipment
Grade names and equivalents
Technical properties
Typical values are for reference only. Final chemistry, mechanical properties, heat treatment, dimensions, inspection, and documentation are confirmed against the applicable specification and MTC/COA before order acceptance.
Chemical composition
| Property | Value | Unit | Condition / standard |
|---|---|---|---|
| Co | balance | wt% | Typical value |
| Cr | 25.0-29.0 | wt% | Typical value |
| Mo | 5.0-6.0 | wt% | Typical value |
| Ni | 1.5-3.5 | wt% | Typical value |
| C | 0.2-0.35 | wt% | Typical value |
| Fe | 3.0 max | wt% | Typical value |
| Mn | 1.0 max | wt% | Typical value |
| Si | 1.0 max | wt% | Typical value |
Mechanical properties
| Property | Value | Unit | Condition / standard |
|---|---|---|---|
| Hardness | 25-35 HRC | HRC | As cast / as deposited |
Physical properties
| Property | Value | Unit | Condition / standard |
|---|---|---|---|
| Density | 8.3 | g/cm3 | Typical |
| Melting range | 1315-1395 | C | Typical |