Cobalt-Chrome Alloy ERCoCr-A-SR (Stress relieved)
Heat-treated state
UNS R30001
Use on large or restrained parts to cut residual stress and crack risk; hardness is essentially unchanged or slightly higher.
Values for the SR condition
Other ERCoCr-A tempers and conditions
ERCoCr-A is listed in 3 conditions; see the grade overview at ERCoCr-A.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AWDefault As-welded deposit | Standard reference condition: 2–3 layer deposit measured on the top layer where iron dilution is <5 %. | 620 | 830 | 1 | 41 HRC | 2 % IACS |
SRThis page Stress relieved | Use on large or restrained parts to cut residual stress and crack risk; hardness is essentially unchanged or slightly higher. | 640 | 800 | 1 | 43 HRC | 2.1 % IACS |
Service-aged / thermally exposed 600–800 °C | Reference for long-term hot-service parts: secondary carbide precipitation raises hardness slightly while ductility drops further. | 650 | 760 | 0.5 | 45 HRC | 1.9 % IACS |
What is ERCoCr-A-SR?
ERCoCr-A-SR is ERCoCr-A heat treated to SR — use on large or restrained parts to cut residual stress and crack risk; hardness is essentially unchanged or slightly higher. ERCoCr-A-SR has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 77% of cobalt-chrome alloy grades. Elongation at break is 1% and the elastic modulus is 212 GPa (30.7 Msi). ERCoCr-A-SR has a density of 8.44 g/cm³ (0.305 lb/in³), lighter than 52% of cobalt-chrome alloy grades. It melts at 1,285°C (2,345 °F). AW is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Readily welded — 55/100, better than 80% of cobalt-chrome alloy grades
ERCoCr-A-SR properties
Typical room-temperature values for ERCoCr-A-SR; 21 are specific to this condition. Other listed values are ERCoCr-A reference data and may not represent this condition. Bars are the position among cobalt-chrome alloy grades.
Physical3
ERCoCr-A-SR has a density of 8.44 g/cm³ (0.305 lb/in³), lighter than 52% of cobalt-chrome alloy grades. It melts at 1,285°C (2,345 °F).
Mechanical15
ERCoCr-A-SR has a yield strength of 640 MPa (92.8 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 77% of cobalt-chrome alloy grades. Elongation at break is 1% and the elastic modulus is 212 GPa (30.7 Msi).
Thermal5
ERCoCr-A-SR is rated for continuous service to 800°C (1,472 °F). It conducts heat at 15.2 W/m·K (8.78 BTU/hr·ft·°F), better than 96% of cobalt-chrome alloy grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
ERCoCr-A-SR conducts electricity at 2.1 % IACS, better than 96% of cobalt-chrome alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 54% of cobalt-chrome alloy grades.
Sustainability4
Producing a kilogram of ERCoCr-A-SR takes about 155 MJ of energy and emits 11.5 kg of CO₂ — more than 52% of cobalt-chrome alloy grades. Typical recycled content is 25%.
Manufacturability8
ERCoCr-A-SR's machinability is not recommended (7/100, worse than 75% of cobalt-chrome alloy grades); weldability good (55/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ERCoCr-A-SR
Is ERCoCr-A easy to machine?
Grind (Al2O3/CBN) or finish-turn with negative-rake carbide/ceramic at 10–25 m/min and heavy rigid setups; the alloy work-hardens and is best sized by lapping for sealing faces.
Can ERCoCr-A be welded?
Preheat steel substrates 250–450 °C, keep interpass heat low, deposit 2–3 layers to beat dilution, and cool slowly under insulation; transverse check cracks are normal and usually acceptable, fusion-line cracking is not.
Can ERCoCr-A be formed, bent or molded?
Not formable — supplied as drawn wire or cast rod; shape is created by deposition, casting or near-net PTA/laser cladding.
What surface finishes work on ERCoCr-A?
Grind/lap to final size; no plating or anodizing needed since the Co-Cr surface is inherently passive and polishes to a mirror finish.
ERCoCr-A 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 |
|---|---|---|
| Cforms Cr7C3/Cr23C6 network | 0.9 – 1.4 | 1.1 |
| Cr | 26 – 32 | 28 |
| W | 3 – 6 | 4.5 |
| Ni | ≤ 3 | 1 |
| Femax, excluding dilution | ≤ 5 | 2 |
| Si | ≤ 2 | 1 |
| Mn | ≤ 1 | 0.5 |
| Mo | ≤ 1 | — |
| Other elements, totalAWS residual limit | ≤ 1 | — |
| Cobalance, nominally ~60 % | balance | — |
ERCoCr-A-SR — frequently asked
What is ERCoCr-A-SR used for?
ERCoCr-A-SR is typically used for hot forging die facing, hot shear blades and extreme wear overlay welding. In short: AWS Stellite 1 filler; high-abrasion overlay consumable; low-ductility hardfacing deposit.
What is the yield strength of ERCoCr-A-SR?
ERCoCr-A-SR has a typical yield strength of 640 MPa (92.8 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 77% of cobalt-chrome alloy grades. Strength varies by condition: see the 3 listed tempers.
Is ERCoCr-A-SR easy to machine?
Not especially — machinability is rated not recommended (7/100, worse than 75% of cobalt-chrome alloy grades). Grind (Al2O3/CBN) or finish-turn with negative-rake carbide/ceramic at 10–25 m/min and heavy rigid setups; the alloy work-hardens and is best sized by lapping for sealing faces.
Can ERCoCr-A-SR be welded?
Yes — weldability is rated good (55/100). Preheat steel substrates 250–450 °C, keep interpass heat low, deposit 2–3 layers to beat dilution, and cool slowly under insulation; transverse check cracks are normal and usually acceptable, fusion-line cracking is not.
What surface finishes work on ERCoCr-A-SR?
Grind/lap to final size; no plating or anodizing needed since the Co-Cr surface is inherently passive and polishes to a mirror finish.
Can ERCoCr-A-SR be formed, bent or molded?
Not formable — supplied as drawn wire or cast rod; shape is created by deposition, casting or near-net PTA/laser cladding.
What is the maximum service temperature of ERCoCr-A-SR?
ERCoCr-A-SR 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-A-AW and ERCoCr-A Aged?
AW is the default condition — standard reference condition: 2–3 layer deposit measured on the top layer where iron dilution is <5 %. Aged: reference for long-term hot-service parts: secondary carbide precipitation raises hardness slightly while ductility drops further. Yield strength is 620 MPa in AW versus 650 MPa in Aged.
Sources
- AWS A5.21/A5.21M — Bare Rods and Electrodes for Surfacing — American Welding Society (2011)
- AWS A5.13 — Surfacing Electrodes for Shielded Metal Arc Welding — American Welding Society (2010)
- Stellite 6 alloy technical data — Kennametal Stellite / Deloro (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Cobalt alloys) — ASM International (1990)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (Hardfacing) — ASM International (1993)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.