Stellite Plates | Cobalt-Based Wear & High-Temperature Protection for Chemical, Oil & Gas, Marine, Pharma & Power
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A coastal refinery‑power complex had accepted that valve seats, turbine erosion shields and pump wear rings in high‑solids, high‑temperature service were “consumables”, replacing tool‑steel and stainless hardfaced parts every turnaround as slurry, cavitation and steam‑side oxidation steadily ate through their surfaces. When the reliability and procurement teams rebuilt those critical wear components with Stellite Plates (cobalt‑based alloys such as Stellite 6 and 6B), they changed the damage mechanism entirely by moving to alloys that combine complex hard carbides in a cobalt‑chromium matrix, with typical casting hardness around 36–46 HRC, tensile strengths around 790 MPa, yield around 660 MPa and the ability to retain significant hardness and wear resistance up to about 500 °C in many grades; subsequent inspections of Stellite‑lined seats and shields showed annual wear rates falling to below about 0.05 mm/year in seawater and steam service and cavitation damage essentially stabilising instead of accelerating over time.
Stellite is a family of cobalt‑based alloys containing chromium, carbon, tungsten and/or molybdenum, engineered to deliver high hardness, excellent mechanical wear resistance, galling resistance and good corrosion resistance, particularly at elevated temperatures. Technical summaries describe Stellite alloys as “cobalt‑based with additions of Cr, C, W and/or Mo” that are “generally resistant to cavitation, corrosion, erosion, abrasion and galling”, with lower‑carbon grades recommended for cavitation and sliding wear and higher‑carbon grades chosen for abrasion and low‑angle erosion in extremely severe conditions.
For procurement heads, plant and design engineers, fabricators, OEM manufacturers and hardware or industrial supply stores supporting chemical, oil & gas, marine, pharma and power‑generation assets, Stellite plates offer a way to turn chronic wear items into long‑life components where tool steels, 410/420, 17‑4PH, 316L and even some nickel alloys fail. Data sheets for Stellite 6 (UNS R30006) show casting tensile strength around 790 MPa, 0.2% yield strength about 660 MPa, elongation less than 1% and hardness in the range 36–46 HRC, alongside seawater corrosion rates below 0.05 mm/year at 22 °C and retention of a “reasonable level of hardness” up to about 500 °C. Producers highlight that Stellite 6 is regarded as the industry standard general‑purpose wear‑resistant alloy with excellent resistance to mechanical and chemical degradation over a wide temperature range, good impact and cavitation‑erosion resistance and the ability to be machined with carbide tools when supplied in wrought forms such as Stellite 6B sheet and plate.
High-quality Stellite Plates ready for industrial use.
Specification Overview
| Supplier & Role | Aurico Alloys LLP – Stellite Plates supplier, stockist, exporter in India to abroad |
|---|---|
| Alloy Description | Cobalt‑based alloys with chromium, carbon, tungsten and/or molybdenum providing high hardness, excellent wear and galling resistance and good corrosion resistance at elevated temperatures |
| Typical Plate Grades | Stellite 6 (UNS R30006) for general‑purpose wear; Stellite 6B (UNS R30016) as wrought plate/sheet with superior toughness and machinability |
| Key Standards (selected) | UNS R30006, R30016; AMS 5387 / AMS 5373 (cast Stellite 6); AMS 5894 (wrought 6B); various ASTM and EN standards via UNS and product approvals |
| Thickness Range | 4.75 mm – 150 mm |
| Performance Focus | Extreme wear, galling, cavitation, erosion and corrosion resistance in high‑temperature and high‑load environments such as valves, turbines, pumps and drilling equipment |
UNS & Equivalent Grades
Stellite 6
| Property | Value |
|---|---|
| UNS number | R30006 |
| Density | 8.44 g/cm3 |
| Melting range | 1250-1360 °C |
Identifiers and physical constants for Stellite 6. A dash means no such designation is published for this grade.
Stellite 12
| Property | Value |
|---|---|
| UNS number | R30012 |
| Density | 8.53 g/cm3 |
| Melting range | 1225-1280 °C |
Identifiers and physical constants for Stellite 12. A dash means no such designation is published for this grade.
Stellite 21
| 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.
Stock & Product Availability
As a Stellite Plates stockist, Aurico Alloys LLP can offer plate and sheet thicknesses suitable for valve seats and gates, pump wear rings and shafts, erosion shields, turbine wear plates and other components in chemical, oil & gas, marine, pharma and power‑generation equipment, using Stellite 6 cast plate or wrought Stellite 6B sheet as appropriate. Commercial information for Stellite 6 plates notes supply to UNS R30006 with standards such as AMS 5387 and AMS 5373, and describes common applications including valve seats, pump shafts, bearings, erosion shields and rolling couples where self‑mated Stellite surfaces run against each other for maximum wear life.
Chemical Composition
Stellite 6
| Element | Min (%) | Max (%) |
|---|---|---|
| Cobalt (Co) | — | Balance |
| Chromium (Cr) | 27 | 32 |
| Tungsten (W) | 3 | 6 |
| Carbon (C) | 0.9 | 1.4 |
Composition limits for Stellite 6. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Stellite 12
| Element | Min (%) | Max (%) |
|---|---|---|
| Cobalt (Co) | — | Balance |
| Chromium (Cr) | 27 | 32 |
| Tungsten (W) | 7.5 | 9.5 |
| Carbon (C) | 1.4 | 2.0 |
Composition limits for Stellite 12. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Stellite 21
| Element | Min (%) | Max (%) |
|---|---|---|
| Cobalt (Co) | — | Balance |
| Chromium (Cr) | 26 | 29 |
| Molybdenum (Mo) | 4.5 | 6.0 |
| Carbon (C) | — | 0.35 |
| Nickel (Ni) | — | 3.0 |
Composition limits for Stellite 21. These are specification limits for the grade, not measured values for a lot; the mill test certificate supplied with your order states the actual analysis.
Mechanical & Physical Properties
| Property (Typical) – Stellite 6 / UNS R30006 | Value |
|---|---|
| Tensile Strength (casting) | ≈790 MPa |
| 0.2% Yield Strength (casting) | ≈660 MPa |
| Elongation (casting) | <<1% in 4D, reflecting high hardness and limited ductility |
| Hardness | ≈36–46 HRC for cast Stellite 6 |
| Seawater Corrosion Rate | Mass loss in seawater below about 0.05 mm/year at 22 °C, with pitting as the primary mechanism rather than general mass loss |
| High-Temperature Performance | Retains a “reasonable level of hardness” and wear resistance up to about 500 °C (≈930 °F); some sources cite effective wear resistance up to around 870 °C in specialised applications |
| Wear & Galling Resistance | Resistant to abrasion, galling, cavitation and low‑angle erosion; widely used self‑mated in critical wear couples |
Applications & Benefits
- Chemical & Oil & Gas: Stellite plates and overlays are used for valve seats and gates, pump shafts and bearings, drilling tools and refinery wear parts where erosion, abrasion, cavitation, galling and corrosive media combine, offering far longer life than tool steels or martensitic stainless steels in high‑temperature, high‑pressure chemical and oil & gas environments.
- Marine & Desalination: In seawater cooling circuits, desalination plants and offshore valves, Stellite 6’s low mass‑loss rate in seawater (below about 0.05 mm/year at 22 °C) and resistance to cavitation and erosion make it ideal for trim parts and erosion shields that must survive brine, sand and cavitation for years.
- Pharma & Power: Power and pharma plants use Stellite plates and facings in steam turbine erosion shields, control‑valve trim, wear plates and high‑clean mechanical interfaces where non‑galling, non‑contaminating surfaces and long wear life reduce downtime and maintain product purity.
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Conclusion
Stellite Plates from Aurico Alloys LLP, supplied to UNS R30006 / R30016 chemistry limits and key standards such as AMS 5387, AMS 5373 and AMS 5894, give chemical, oil & gas, marine, pharma and power‑generation users cobalt‑based alloys that combine high hardness, excellent wear and galling resistance, seawater and high‑temperature corrosion resistance and proven service life in valves, turbines, pumps and critical wear components are your most demanding erosive, cavitating and high‑temperature contact surfaces still relying on lower‑alloy steels and standard stainless overlays instead of optimised Stellite plates?