Alloy 6B is a wrought cobalt–chromium–tungsten–carbon alloy designed for wear environments where seizing, galling and abrasion are present. This datasheet presents the material within the American (SAE-AMS / UNS) standard system.
It is the wrought (forged) form of the classic Co-Cr-W "Alloy 6" wear material. The forged microstructure — a cobalt-based matrix with dispersed chromium/tungsten carbides — gives Stellite 6B superior toughness, weldability, abrasive/erosive wear properties and corrosion resistance compared with cast or weld-deposited Stellite 6: its Charpy impact toughness is roughly four times that of cast Stellite 6. Its wear resistance is inherent in the alloy and is not the result of cold working, heat treating or any other method.
Thanks to its low coefficient of friction it resists seizing and galling, allowing sliding contact with other metals without metal pick-up in many cases — valuable where lubrication is impractical. It also offers good hot hardness and corrosion resistance in a variety of media. Typical applications include aerospace bearings, steam-turbine erosion shields and fan blades, wear plates, tunnel-boring seals, gears, sleeves and bushings, and drilling/exploration tooling.
Values per manufacturer (Kennametal Stellite) data.
| Property | Value | Unit |
|---|---|---|
| Density | 8.39 | g/cm³ |
| Melting range | 1265–1357 | °C |
| Young's modulus (20 °C) | 248 | GPa |
| Thermal conductivity (20 °C) | 14.8 | W/m·K |
| Coefficient of thermal expansion (20–100 °C) | 13.9 | µm/m·°C |
| Hardness (typical) | 36–45 | HRC |
| Magnetic response | Slightly magnetic | — |
| Structure | Cobalt matrix + Cr/W carbides | — |
Nominal composition per AMS 5894 (UNS R30016).
| Element | Symbol | Value | Role in Alloy |
|---|---|---|---|
| Cobalt | Co | Balance (~59) | Base element; wear + galling resistance |
| Chromium | Cr | 28.0–30.0 | Carbides + corrosion + oxidation resistance |
| Tungsten | W | 4.0–6.0 | Solid-solution + carbide strengthening |
| Carbon | C | 0.9–1.4 | Forms hard chromium/tungsten carbides |
| Nickel | Ni | ~3.0 | Toughness |
| Iron | Fe | ~3.0 | Residual |
| Manganese | Mn | ~1.5 | Deoxidiser |
| Silicon | Si | ~0.7 | Deoxidiser |
Nominal: Co-29Cr-4.5W-1.2C. The hard carbides dispersed in the tough cobalt matrix give the wear resistance; the wrought form provides higher toughness than cast Stellite 6.
Typical room-temperature properties, wrought condition.
| Property | Value | Source |
|---|---|---|
| Ultimate tensile strength | ~1010 MPa | Wrought |
| 0.2% proof strength (yield) | ~625 MPa | Wrought |
| Elongation at break | ~11 % | Wrought (vs ~1% for cast Stellite 6) |
| Hardness | ~36–45 HRC | Wrought |
| Charpy impact toughness | ~4× cast Stellite 6 | Kennametal |
Wear resistance is inherent and not developed by cold work or heat treatment. The wrought microstructure provides substantially higher toughness and ductility than the cast alloy. Values are typical; confirm against the mill test certificate.
| Property / Environment | Performance | Notes |
|---|---|---|
| Abrasive wear | Outstanding | Hard Cr/W carbides |
| Erosive wear | Outstanding | Superior to cast Stellite 6 (wrought) |
| Seizing / galling | Outstanding | Low coefficient of friction; sliding without pick-up |
| Hot hardness | Excellent | Retains hardness at temperature |
| Corrosion (various media) | Excellent | Good in food-handling / chemical media |
| High-temperature oxidation | Good | Cr₂O₃ scale |
| Cavitation / sliding wear | Excellent | Cobalt base |
A wrought cobalt-base wear alloy; its wear resistance is inherent and is not developed by heat treatment or cold work. No hardening heat treatment is required or applied to develop wear properties.
Stress relief (if required) can be carried out at moderate temperature per manufacturer guidance. The alloy is supplied in the wrought condition with its characteristic carbide structure; the properties are intrinsic to the composition and forged microstructure rather than to any post-process heat treatment.
The wrought form gives Stellite 6B better weldability than cast Stellite 6. Sheets can be formed and/or welded in place to cover high-wear areas with minimal heat input, allowing wear protection to be fabricated where and when needed.
| Process | Applicability | Notes |
|---|---|---|
| Welding (in-place repair / cladding) | Good | Minimal heat input; for covering wear areas |
| Forming | Good | Wrought sheet can be formed |
| Fabrication | Good | Superior to cast Stellite 6 |
Follow manufacturer guidance; as a high-carbon Co-Cr-W alloy, control heat input to manage cracking risk.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Hardness | High (36–45 HRC); rigid setup, sharp carbide/CBN tooling |
| Wear resistance | High — abrasive to tooling; low speeds, positive approach |
| Grinding | Often preferred for finishing |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Wrought forming | Sheet/bar can be formed (wrought advantage) |
| Welding | In-place cladding of wear surfaces |
| Finishing | Grinding common for hard wear surfaces |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Aerospace | Bearings, bushings, wear parts | Wear + galling resistance + toughness |
| Power generation | Steam-turbine erosion shields, fan blades | Erosion + hot hardness |
| Industrial | Wear plates, gears, sleeves, bushings | Abrasion + galling resistance |
| Mining / tunnelling | Tunnel-boring seals, drilling/exploration tooling | Abrasion + corrosion resistance |
| Food / chemical | Wear components in corrosive media | Wear + corrosion resistance |
| Product Form | Standard | Notes |
|---|---|---|
| Round bar | AMS 5894 | Wrought; 0.312–6.000 in dia |
| Flat bar, sheet and plate | AMS 5894 | Wrought; 0.031–1.000 in thick |
| Bushings | UNS R30016 | Wrought |
| Custom sizes | On request | — |
Wrought cobalt-base wear-resistant alloy. UNS R30016; AMS 5894. (Stellite is a registered trademark of Kennametal Inc.) Distinct from cast Stellite 6 (UNS R30006).
| Alloy | Co | Cr % | Other | Best Used For |
|---|---|---|---|---|
| Alloy 6B | bal | 28–30 | W 4.5, C 1.2 (wrought) | Wrought wear alloy; 4x toughness of cast 6 |
| Stellite 6 | bal | 27–32 | W 4.5, C 1.1 (cast/weld) | Cast/hardfacing wear; lower toughness |
| Stellite 12 | bal | ~29 | W 8, C 1.4 | Harder hardfacing; higher wear/lower toughness |
| Stellite 21 | bal | ~28 | Mo 5.2, C 0.25 | Lower-C; cavitation/impact + corrosion |
| Haynes 25 / L605 | bal | 19–21 | W 15, Ni 10 | Fabricable high-temp Co alloy |




