Cobalt-Chrome Alloy ERCoCr-B
UNS R30006
ERCoCr-B (UNS R30006) is the AWS cobalt hardfacing filler classification matched to Stellite 6, the most widely used of the Co-Cr-W overlay consumables.
Reference datasheet — ERCoCr-B is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the AW condition
ERCoCr-B tempers and conditions
ERCoCr-B is supplied in 3 conditions, soft to hard. AW is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AWDefault As-welded deposit | Standard reference condition: fully undiluted Co-Cr-W overlay as deposited by GTAW/PTA/oxy-fuel, no post-weld heat treatment. | 620 | 830 | 1 | 45 HRC | 2 % IACS |
As cast | Solid cast parts (valve trim, nozzles, wear inserts) made to the same Co-Cr-W chemistry when a full-section wear alloy rather than an overlay is required. | 620 | 830 | 1 | 46 HRC | 2 % IACS |
Stress relieved | Choose when the substrate (e.g. Cr-Mo steel) requires PWHT or when overlay cracking risk on thick sections must be reduced; overlay hardness is essentially unchanged or slightly higher from carbide precipitation. | 640 | 830 | 1 | 46 HRC | 2 % IACS |
Supply forms, finishes and certifications
Ways ERCoCr-B is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
AW-1L | As Welded | Surface finish |
PTA | PTA / laser clad powder deposit | Coating |
RCoCr-B | Bare cast rod deposit | Supply option |
What is ERCoCr-B?
ERCoCr-B (UNS R30006) is the AWS cobalt hardfacing filler classification matched to Stellite 6, the most widely used of the Co-Cr-W overlay consumables. It balances abrasion, corrosion and moderate impact resistance, with deposit properties of 830 MPa tensile strength, 1 % elongation, 45 HRC and service to 800 °C, and is available as bare wire, cast rod (RCoCr-B), PTA powder and coated electrodes. It remains a hard carbide deposit: not formable, grind-only and prone to transverse check cracking. ERCoCr-A is harder; Stellite F is tougher. ERCoCr-B has a density of 8.6 g/cm³ (0.311 lb/in³), heavier than 63% of cobalt-chrome alloy grades. It melts at 1,280°C (2,336 °F). ERCoCr-B has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 67% of cobalt-chrome alloy grades. Elongation at break is 1% and the elastic modulus is 225 GPa (32.6 Msi).
What is ERCoCr-B used for?
- valve seat overlay welding
- pump sleeves
- steam turbine wear surfaces
Advantages
- Low embodied carbon — 9.5 kg CO₂/kg, better than 87% of cobalt-chrome alloy grades
Limitations
- Low fracture toughness — 11 MPa·√m (10 ksi·√in), worse than 97% of cobalt-chrome alloy grades
ERCoCr-B properties
Typical room-temperature values for ERCoCr-B-AW; bars are the position among cobalt-chrome alloy grades.
Physical3
ERCoCr-B has a density of 8.6 g/cm³ (0.311 lb/in³), heavier than 63% of cobalt-chrome alloy grades. It melts at 1,280°C (2,336 °F).
Mechanical16
ERCoCr-B has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 67% of cobalt-chrome alloy grades. Elongation at break is 1% and the elastic modulus is 225 GPa (32.6 Msi).
Thermal5
ERCoCr-B is rated for continuous service to 800°C (1,472 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), better than 64% of cobalt-chrome alloy grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
ERCoCr-B conducts electricity at 2 % IACS, better than 79% of cobalt-chrome alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), worse than 71% of cobalt-chrome alloy grades.
Sustainability4
Producing a kilogram of ERCoCr-B takes about 130 MJ of energy and emits 9.5 kg of CO₂ — less than 89% of cobalt-chrome alloy grades. Typical recycled content is 20%.
Manufacturability7
ERCoCr-B's machinability is not recommended (8/100, worse than 64% of cobalt-chrome alloy grades); weldability fair (35/100); formability not recommended (3/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the cobalt-chrome alloy family
Yield strength against density for every cobalt-chrome alloy grade FabDigit runs. ERCoCr-B is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ERCoCr-B
Is ERCoCr-B easy to machine?
Finish by grinding (SiC/CBN wheels) or lapping; if turning is unavoidable use negative-rake carbide/ceramic, rigid setup, low speed and heavy feed — no HSS tooling.
Can ERCoCr-B be welded?
Deposit with GTAW, oxy-acetylene, PTA or laser cladding; preheat 300–500 °C for steel substrates, keep interpass hot, limit dilution and cool slowly under insulation — some transverse check cracking is normal and generally acceptable.
Can ERCoCr-B be formed, bent or molded?
Not formable: the deposit is a hard hypereutectic carbide structure with ~1 % elongation, so all shaping is done by weld deposition, casting or grinding.
ERCoCr-B chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Chigher than ERCoCr-A, gives more Cr-W carbide | 1 – 1.7 | 1.35 |
| Cr | 26 – 32 | 29 |
| W | 7 – 9.5 | 8.3 |
| Ni | ≤ 3 | |
| Femax (undiluted deposit / filler analysis) | ≤ 3 | |
| Si | ≤ 2 | 1 |
| Mn | ≤ 2 | 0.5 |
| Mo | ≤ 1 | |
| Other, total | ≤ 1 | |
| Co | balance |
What surface finishes work on ERCoCr-B?
Grinds and laps to a mirror sealing face with excellent gall resistance; no plating or coating is needed, and passivation/pickling is only for cleanup of weld oxide.
Equivalent designations
Standards and trade names that resolve to Cobalt-Chrome Alloy ERCoCr-B in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- R30006
- Also called
- AWS A5.21 ERCoCr-BAWS A5.21 RCoCr-B
How much does ERCoCr-B cost?
ERCoCr-B is a high-cost cobalt-chrome alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ERCoCr-B — frequently asked
What is ERCoCr-B used for?
ERCoCr-B is typically used for valve seat overlay welding, pump sleeves and steam turbine wear surfaces. In short: most-used cobalt hardfacing filler; balanced wear and corrosion; stellite 6 equivalent deposit.
What is the yield strength of ERCoCr-B?
ERCoCr-B has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 67% of cobalt-chrome alloy grades. Strength varies by condition: see the 3 listed tempers.
Is ERCoCr-B easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 64% of cobalt-chrome alloy grades). Finish by grinding (SiC/CBN wheels) or lapping; if turning is unavoidable use negative-rake carbide/ceramic, rigid setup, low speed and heavy feed — no HSS tooling.
Can ERCoCr-B be welded?
With care — weldability is rated fair (35/100). Deposit with GTAW, oxy-acetylene, PTA or laser cladding; preheat 300–500 °C for steel substrates, keep interpass hot, limit dilution and cool slowly under insulation — some transverse check cracking is normal and generally acceptable.
What surface finishes work on ERCoCr-B?
Grinds and laps to a mirror sealing face with excellent gall resistance; no plating or coating is needed, and passivation/pickling is only for cleanup of weld oxide.
Can ERCoCr-B be formed, bent or molded?
Not formable: the deposit is a hard hypereutectic carbide structure with ~1 % elongation, so all shaping is done by weld deposition, casting or grinding.
What is the maximum service temperature of ERCoCr-B?
ERCoCr-B is rated for continuous use to about 800°C (1,472 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ERCoCr-B-AW and ERCoCr-B-SR?
AW is the default condition — standard reference condition: fully undiluted Co-Cr-W overlay as deposited by GTAW/PTA/oxy-fuel, no post-weld heat treatment. SR: choose when the substrate (e.g. Cr-Mo steel) requires PWHT or when overlay cracking risk on thick sections must be reduced; overlay hardness is essentially unchanged or slightly higher from carbide precipitation. Yield strength is 620 MPa in AW versus 640 MPa in SR.
How much does ERCoCr-B cost?
ERCoCr-B is a high-cost cobalt-chrome alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- AWS A5.21/A5.21M — Specification for Bare Electrodes and Rods for Surfacing — American Welding Society (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Cobalt Wear-Resistant Alloys) — ASM International (1990)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (Hardfacing) — ASM International (1993)
- Stellite 12 alloy technical data (rod, wire, powder) — Kennametal Stellite / Deloro (2023)
- UNS R30012 / R30006 alloy designations (Metals & Alloys in the Unified Numbering System) — SAE/ASTM (2017)
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.