Stellite is a family of cobalt-chromium super alloys built for wear rather than for load. Hard chromium and tungsten carbides dispersed through a cobalt matrix give these alloys their resistance to abrasion, galling, cavitation and hot corrosion, and that same carbide network is what makes them hard, brittle and impossible to forge. Three of the four grades here — alloys 3, 6 and 12 — carry 1–2.3% carbon and have elongation below 1%; they are cast, powder consolidated or deposited as overlay, then finish ground. Alloy 21 is the exception, with carbon capped at 0.25% and molybdenum in place of tungsten, giving 5–10% elongation and genuine load-carrying capability. Exotic Alloy supplies all four as castings, weld overlay, thermal spray coatings and Stellite-hardfaced fastener and valve components.
Try adjusting your search criteria or contact us for custom alloys.
Stellite cannot be rolled into bar and cut into bolts the way a nickel alloy can. There are three practical routes and we supply all of them: solid Stellite components investment cast to near-net shape and finish ground; Stellite-hardfaced fasteners, where a stainless, carbon or nickel alloy body carries the thread and preload while a Stellite overlay takes the wear on the sealing face; and Stellite 6B (UNS R30016), the wrought rolled version of alloy 6, where a genuinely wrought load-bearing section is required. Alloy 21 is the most ductile and machinable of the four and is usually the right choice where a part must resist wear and carry load. Tell us the duty and our technical team will confirm the route before you order.
The carbide volume fraction that makes Stellite wear-resistant also destroys cutting edges, so conventional turning and milling are not practical on alloys 3, 6 and 12 and high-speed steel tooling is useless on any of them. Components are cast close to final shape specifically to minimise stock removal, then finished by grinding with silicon carbide or diamond wheels, by EDM, or by single-point work with ceramic and CBN inserts. Alloy 21, with its much lower carbon, is the one grade that takes conventional carbide machining. Cobalt dust is a respiratory hazard, so extraction is mandatory on every dry grinding operation we run.
Hardness rises and ductility falls as carbon content increases across the Co-Cr-W grades.
| Alloy Grade | UNS | AWS Filler | Nominal C / Cr / W or Mo | Hardness | Elongation |
|---|---|---|---|---|---|
| Stellite 21 | R30021 | ERCoCr-E | 0.25% C / 27% Cr / 5.5% Mo | 33–37 HRC | 5–10% |
| Stellite 6 | R30006 | ERCoCr-A | 1.2% C / 28% Cr / 4.5% W | 36–45 HRC | < 1% |
| Stellite 12 | R30012 | ERCoCr-B | 1.8% C / 30% Cr / 8.3% W | 45–51 HRC | < 1% |
| Stellite 3 | R30001 / R30103 | – | 2.3% C / 30.5% Cr / 12.5% W | 48–63 HRC | < 1% |
Listed in order of increasing carbon content. Alloy 21 uses molybdenum in place of tungsten. UNS R30001 designates cast Stellite 3 and R30103 the powder metallurgy form.
We are committed to delivering zero-defect Stellite components. All products undergo rigorous testing including PMI (Positive Material Identification), deposit and substrate hardness verification, dye penetrant inspection of hardfacing deposits, dimensional inspection, and material traceability with EN 10204 3.1 certification.
Exotic Alloy exports Stellite components and hardfaced fasteners to valve makers, pump builders, power generation and oil and gas clients worldwide. Our dedicated logistics team ensures secure export packaging and timely deliveries by sea and air freight with full customs documentation support.