ECoCr-A Cobalt 6 Welding Electrode - Stellite 6 | AWS A5.13 Supplier in India
Nicorex Alloys is a certified supplier of cobalt‑ and nickel‑based welding consumables based in Mumbai, India. Our ECoCr-A electrode meets AWS A5.13 and ASME SFA 5.13 standards. It is also known as Cobalt Alloy 6, CoCr-A, UNS W73006 (for the weld deposit), and UNS R30006 (for the alloy). The weld deposit is a cobalt‑chromium‑tungsten (Co‑Cr‑W) alloy containing about 13% chromium carbides. Its typical chemistry is 28-29% chromium, 4-5% tungsten, 1.0-1.1% carbon, with the balance cobalt, giving high wear and galling resistance.
ECoCr-A Stellite 6 is a cobalt‑chromium‑tungsten hardfacing alloy known worldwide for its excellent galling and wear resistance, especially when compared with typical iron‑base overlays. Its chromium carbides stay hard up to about 500°C (930°F) and provide effective wear resistance to roughly 650°C (1200°F). The weld deposit is non‑magnetic and does not undergo allotropic transformation at service temperatures. Nicorex Alloys manages every production lot under ISO 9001 and ISO 14001 systems. Each shipment includes MTC 3.1 certificates (per EN 10204) and weld deposit chemical analysis reports, so buyers can verify traceability and composition. We support customers with competitive pricing, ready stock, and fast dispatch within India.
ECoCr-A electrodes are available in 3.2 mm, 4.0 mm, and 5.0 mm diameters, in 350-400 mm lengths, for use with DCEP or AC. It is mainly used in applications that include valve seats, pump shafts, turbine blades, shear blades, and erosion‑resistant surfaces used in oil and gas, power generation, and valve manufacturing.
ECoCr-A Stellite 6 Welding Electrode Specifications
| AWS Class | ECoCr-A |
|---|---|
| AWS / ASME Standard | AWS A5.13 / A5.13M, SFA 5.13 |
| UNS Number (Electrode Deposit) | W73006 |
| UNS Number (Alloy) | R30006 |
| AMS Standard | AMS 5788 |
| Welding Process | SMAW (Shielded Metal Arc / Stick / MMA) |
| Electrode Coating Type | Basic (low-hydrogen type) |
| Polarity / Current | DCEP (DC+); also AC |
| Welding Positions | All positions (F, V, OH, H); flat preferred |
| Deposit Hardness (As-Welded) | 36-45 HRC (2-3 layers on mild steel) |
| Alloy Base | Cobalt-Chromium-Tungsten (Co-Cr-W) |
AWS Classification ECoCr-A - What Each Character Means
| Character(s) | Meaning |
|---|---|
| E | Electrode (covered/coated for SMAW) |
| Co | Cobalt-base alloy deposit |
| Cr | Chromium is the principal alloying element after cobalt |
| -A | Alloy variant A: nominally 28Cr-4.5W-1.1C-bal Co (Stellite 6 chemistry) |
This classification helps buyers distinguish ECoCr-A from its sister alloys. ECoCr-B (Cobalt 12 / Stellite 12) carries ~16% carbides. ECoCr-C (Cobalt 1 / Stellite 1) is the highest carbide variant at ~19%. ECoCr-E (Stellite 21) is a low-carbon, ductile grade. All four are cobalt-chromium hardfacing electrodes with different carbon levels, carbide volumes, and hardness ranges.
Chemical Composition of ECoCr-A Weld Deposit (%)
ECoCr-A weld deposit chemistry is governed by AWS A5.13. The table lists specification limits and typical undiluted values.
| Element | Carbon (C) | Chromium (Cr) | Tungsten (W) | Cobalt (Co) | Iron (Fe) | Nickel (Ni) | Silicon (Si) | Manganese (Mn) | Molybdenum (Mo) | Other (each) |
|---|---|---|---|---|---|---|---|---|---|---|
| AWS A5.13 Spec (%) | 0.70 – 1.40 | 25.0 – 32.0 | 3.0 – 6.0 | Remainder | 5.0 max | 3.0 max | 2.0 max | 2.0 max | 1.0 max | 1.0 max |
| Typical Deposit (%) | 1.10 | 25.8 – 29.0 | 4.5 | Balance | 3.2 | 1.9 | 1.0 | 0.1 | 0.1 | – |
Actual deposit chemistry varies with base metal dilution, layer count, and welding parameters. First-layer deposits on carbon steel show higher iron content. Minimum 2-3 layers recommended for full alloy chemistry.
ECoCr-A Weld Deposit Hardness and Mechanical Behaviour
| Property | As-Welded Hardness (2-3 layers) | Typical Hardness (2 layers) | Three-Layer Deposit | Hot Hardness Retention | Functional Wear Resistance Limit | Charpy V-Notch Impact | Tensile / Yield / Elongation |
|---|---|---|---|---|---|---|---|
| Value | 36 – 45 HRC | 38 – 40 HRC | 40 – 45 HRC | Reasonable to 500°C (930°F) | ~650°C (1200°F) | Not applicable per AWS A5.13 | Not specified (NS) per AWS A5.13 |
Base Metals Compatible with ECoCr-A Hardfacing Overlay
ECoCr-A bonds well with many ferrous and non‑ferrous base metals, forming a strong metallurgical bond. Preheat and buffer layer guidance for CoCr-A cobalt overlay is summarised below.
| Substrate | Typical Grades | Preheat (°C) | Buffer Layer? |
|---|---|---|---|
| Carbon Steel | A105, A106, SA516 Gr.70 | 200-315 | Optional (309L / Inconel 625) |
| Cr-Mo Steel | A182 F11, F22, F91, 4130 | 300-400 | Recommended (309L / Inconel 625) |
| Martensitic SS | 410, CA15, CA6NM | 200-300 | Recommended |
| Austenitic SS | 304, 316, CF8M | 10-100 | Optional (sensitisation risk) |
| Duplex SS | 2205, 2507 | ~100 | Recommended (Inconel 625) |
| Nickel Alloys | Inconel 600, 625, Monel 400 | None-150 | Not required |
| Cobalt Alloys | Stellite 6 castings | 300-500 | Not required; use Stellite 21 |
Available Electrode Sizes and Recommended Welding Parameters
| Diameter | Length | Current (DCEP) | Also AC |
|---|---|---|---|
| 3.2 mm (1/8″) | 350 mm (14″) | 90 – 120 A | Yes |
| 4.0 mm (5/32″) | 350 mm (14″) | 135 – 170 A | Yes |
| 5.0 mm (3/16″) | 400 mm (16″) | 170 – 210 A | Yes |
- Arc Type: Short arc, stringer beads. Avoid wide weaving to control dilution.
- Preheat (Carbon / Low-Alloy Steel): 200-315°C (400-600°F); higher for C.E. > 0.45.
- Preheat (Austenitic Stainless): 10-100°C; keep low to prevent sensitisation.
- Preheat (Duplex Stainless): ~100°C (200°F) maximum. Overheating risks sigma phase.
- Interpass: Maintain at or above preheat. Don’t exceed 315°C (600°F) for C-Mn steels.
- Post-Weld: Slow cool in vermiculite or ceramic blanket. PWHT per base metal code for Cr-Mo steels.
- Layers: Minimum 2 for full chemistry; 3 for full hardness.
- Buffer Layer: Consider 309L or Inconel 625 butter layer on crack-sensitive substrates.
Note: ECoCr-A is a hardfacing overlay electrode, not a joining consumable. Hardfacing qualifies as a special process per ASME Section IX QW-251.4 / QW-216 (HFO). F-Number = F-71.
Get ECoCr-A Cobalt 6 Welding Electrode at Competitive Prices
Industrial Hardfacing Applications of ECoCr-A (Cobalt 6) Welding Electrode
ECoCr-A cobalt 6 hardfacing electrode serves 6 major industries, each relying on the alloy’s anti-galling, cavitation erosion, and hot hardness properties.
- Valve Manufacturing and Flow Control: ECoCr-A is widely used to hardface valve seats and trims so metal-to-metal sealing surfaces resist galling and leakage on common valve materials such as A105, A182 F22, F91, and CF8M.
- Power Generation- Steam Turbines and Boiler Components: In steam power plants, ECoCr-A protects turbine blades and steam valve components by retaining hardness and wear resistance in continuous high-temperature steam, while Tribaloy T-400C is preferred above about 650°C.
- Oil and Gas - Upstream, Midstream, Downstream: Operators use ECoCr-A on choke valves, wellheads, Christmas tree parts, and FCC internals to combat sand erosion and galling on high-pressure sealing surfaces, checking NACE MR0175 limits in sour H₂S service.
- Pumps, compressors, and rotating equipment: ECoCr-A overlays on shafts, sleeves, wear rings, impellers, and seal faces help prevent cavitation damage and galling in tight-clearance parts.
- Metal processing, tooling, and cutting: ECoCr-A protects shear blades, extrusion screws, bushings, dies, and saw tips from high-temperature adhesive and abrasive wear.
- Automotive and engine components: ECoCr-A on exhaust valve seats and faces above 500°C keeps its hardness and resists corrosion from fuel-ash deposits.
Storage, Handling and Pre-Use Conditioning of ECoCr-A Electrodes
Proper storage of cobalt hardfacing electrodes is critical. Electrodes ship in hermetically sealed cans or moisture-resistant cartons. Unopened cans don’t require baking.
After opening, store in a heated holding oven at 100-150°C (200-300°F). If exposed to humidity, bake at 150°C (300°F) for 1 hour before use. Do not leave electrodes outside the oven for more than 4 hours; return between shifts. Maximum 2 re-dry cycles are permitted. Moisture in the coating causes porosity, hydrogen embrittlement in the HAZ, and poor slag removal.
How to Order ECoCr-A (Cobalt 6) Electrode from Nicorex Alloys
To request a quotation for ECoCr-A welding electrodes, contact Nicorex Alloys with these details:
- AWS Classification - ECoCr-A (or trade name, e.g., Stellite 6 type electrode)
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Quantity - kg
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Diameter(s) - 3.2 mm, 4.0 mm, or 5.0 mm
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Packaging Preference - Sealed cans, vacuum packs
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Third-Party Approvals - DNV, ABS, BV, Lloyd's, TUV
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Test Certificates - Standard MTC 3.1 or extended (PMI, additional tests)
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Delivery Destination & Shipping Terms - Ex-Works, FOB, CIF
- Project Specification - NACE, ASME III, MIL-spec
Nicorex Alloys supplies matching cobalt consumables across processes: ECoCr-A electrodes, ERCoCr-A TIG rods, and ERCCoCr-A MIG wire as a coordinated set.