ECoCr-E Welding Electrode — Cobalt 21 (Stellite 21) Electrode Supplier in India
Nicorex Alloys is an ISO 9001 and ISO 14001 certified stockist, supplier and distributor of cobalt hardfacing consumables based in Mumbai, India. We carry batch-tested stock of ECoCr-E (Cobalt 21) coated electrodes manufactured to AWS A5.13 / ASME SFA 5.13 with EN 10204/3.1B mill test certificates on every lot.
ECoCr-E is a molybdenum-bearing cobalt-chromium hardfacing electrode in the standard CoCr family, CoCrMo (cobalt-chromium-molybdenum) alloy, fundamentally different from the CoCrW (tungsten-bearing) ECoCr-A, ECoCr-B and ECoCr-C variants. AWS A5.13 specifies approximately 27.9% Cr, 5.2% Mo, 2.5% Ni and low carbon ≤0.35%. That molybdenum content gives ECoCr-E superior corrosion resistance in reducing acids (H₂SO₄, HCl) and sour gas environments where tungsten-bearing cobalt alloys fall short. Deposit hardness sits at 27-40 HRC (290-430 HV) as-welded, but the deposit can work harden up to 48 HRC (550 HV) during metal-to-metal contact. A property that no other standard cobalt hardfacing alloy offers. UNS designations are W73021 (electrode) and R30021 (alloy). Density is 8.33 g/cm³; melting range 1295–1435°C. Available in 2.4, 3.2, 4.0, and 5.0 mm diameters, polarity is DCEP.
The solid-solution-strengthened CoCrMo matrix with low carbide volume makes ECoCr-E the toughest standard cobalt alloy. Previously known as Stellite 8, it excels where impact, thermal shock, corrosion and cavitation dominate rather than hard-particle abrasion. Applications include petrochemical valve trim, forging and stamping dies, duplex stainless steel valve hardfacing, sour gas valve service and cavitation-resistant overlays for nuclear and marine equipment.
ECoCr-E Coated Electrode Technical Specifications
We at Nicorex provide ECoCr-E Coated Electrode Classifications and parameters. Take note of the following table before ordering.
| AWS Classification | ECoCr-E |
|---|---|
| UNS Designation | W73021 (electrode) / R30021 (alloy) |
| Governing Specification | AWS A5.13 / A5.13M:2010 |
| ASME Specification | SFA 5.13 |
| Welding Process | SMAW (Shielded Metal Arc Welding) |
| Electrode Coating | Basic |
| Polarity / Current | DCEP (DC+) |
| Welding Positions | Flat and horizontal recommended |
| Deposit Hardness | 27–40 HRC as-deposited; work hardens to 48 HRC |
| Alloy System | CoCrMo (Cobalt-Chromium-Molybdenum) |
AWS A5.13 ECoCr-E Classification Breakdown
| Character(s) | Meaning |
|---|---|
| E | Electrode — covered/coated electrode for SMAW |
| Co | Cobalt-base alloy deposit |
| Cr | Chromium is a principal alloying element |
| -E | Fifth composition variant — designates a CoCrMo (molybdenum-bearing) system, NOT a CoCrW tungsten variant like -A, -B, -C |
ECoCr-E Weld Deposit Chemical Composition
| Element | Carbon (C) | Chromium (Cr) | Molybdenum (Mo) | Nickel (Ni) | Tungsten (W) | Iron (Fe) | Silicon (Si) | Manganese (Mn) | Cobalt (Co) |
|---|---|---|---|---|---|---|---|---|---|
| AWS A5.13 Range (%) | 0.15 – 0.40 | 24 – 29 | 4.5 – 6.5 | 2.0 – 4.0 | 0.50 max | 5.0 max | 2.0 max | 1.5 max | Remainder |
| Typical Deposit (%) | 0.2 | 27.9 | 5.2 | 2.5 | 0.17 | 3.4 | 0.7 | 0.5 | Balance |
All-Weld-Metal Mechanical Properties of ECoCr-E Deposits
| Property | Hardness (as-deposited) | Hardness (work-hardened) | Tensile Strength | Yield Strength (0.2%) | Impact Resistance | Abrasion Resistance | Corrosion Resistance |
|---|---|---|---|---|---|---|---|
| Value | 27–40 HRC (290–430 HV) | Up to 48 HRC (550 HV) | ~710 MPa (~103 ksi) — cast form | ~565 MPa (~82 ksi) — cast form | Best among standard cobalt hardfacing alloys | Good — not for severe hard-particle abrasion | Superior to CoCrW alloys in reducing environments |
Base Metal Compatibility and P-Number Matrix
| Base Metal Group | P-Number | Preheat | Notes |
|---|---|---|---|
| Carbon Steel (A36, A516) | P-1 | 100–200°C | Standard practice |
| Cr-Mo Steel (F11, F22) | P-4, P-5A/B | 200–400°C | 309L buffer recommended |
| Tool Steel (H13) | — | 400°C | Annealed substrate required |
| Austenitic SS (304, 316) | P-8 | Low preheat | Compatible |
| Duplex SS (2205, 2507) | P-10H | Minimal | ECoCr-E preferred over ECoCr-A |
| Martensitic SS (410, 420) | P-6 | 200–350°C | Preheat to avoid HAZ cracking |
ASME Section IX: F-Number F-71, A-Number not applicable. Multiple layers are acceptable.
Recommended Welding Parameters for ECoCr-E Electrodes
| Diameter | Length | Current (DCEP) |
|---|---|---|
| 2.4 mm (3/32″) | 300 mm | 60 – 90 A |
| 3.2 mm (1/8″) | 350 mm | 90 – 130 A |
| 4.0 mm (5/32″) | 350 mm | 130 – 175 A |
| 5.0 mm (3/16″) | 350 mm | 170 – 220 A |
Get ECOCR-E Welding Electrodes at Competitive Prices
ECoCr-E (Stellite 21) in Critical-Service Hardfacing Applications
- Petrochemical and Chemical Processing Valve Hardfacing The preferred alloy for valve trim in chemical plants handling reducing acids (H₂SO₄, HCl). Gate valve seats, globe valve discs, and control valve cages benefit from Mo-driven corrosion resistance that CoCrW alloys lack.
- Power Generation — Steam Valve and Turbine Component Overlay Heritage from jet engine applications. ECoCr-E provides thermal shock resistance for steam valve seats and turbine blade edge overlays. Deposits withstand thermal cycling without craze cracking.
- Oil and Gas — Sour Gas Valve Service The Mo-bearing CoCrMo matrix resists H₂S environments. Used for wellhead valve seats, choke valve internals, and subsea valve parts.
- Duplex Stainless Steel Valve Manufacturing ECoCr-E is the recommended choice for hardfacing duplex stainless steel (2205, 2507) valves. ECoCr-A requires excessive preheat on duplex substrates, promoting sigma phase. ECoCr-E allows crack-free deposition at low interpass temperatures.
- Forging and Hot Stamping Die Repair Impact resistance and thermal shock tolerance make ECoCr-E ideal for worn forging dies, hot shear blades, extrusion dies, and piercing plugs.
- Nuclear and Marine — Cavitation-Resistant Overlays Outstanding cavitation erosion resistance suits nuclear valve internals, pump impeller overlays, and marine fluid control equipment.
Storage, Handling and Re-Drying Procedures for ECoCr-E Electrodes
ECoCr-E electrodes must be stored in original sealed packaging in a clean, dry and temperature-controlled area at 15-25°C and below 50% relative humidity to prevent moisture absorption. If exposed to moisture, re-dry at 250-300°C for 1-2 hours per general cobalt hardfacing practice, then transfer immediately to a holding oven at 100-150°C until use. For critical welding, use electrodes within 4 hours of removal from heated storage.
Protect electrodes from oil, grease, dust and other contaminants, as cobalt alloy weld deposits are sensitive to carbon pickup that can alter chemistry and performance. Store ERCoCr-E TIG rods in sealed tubes away from moisture and shop contaminants. Keep ERCoCr-E wire spools dry, using desiccant packs if unsealed. Avoid dropping or bending electrodes, as the brittle cobalt alloy core may fracture.
Parameters are based on general practice; confirm ECoCr-E-specific TDS with the manufacturer.
How to Order ECoCr-E Welding Electrodes from Nicorex Alloys
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AWS Classification Required - ECoCr-E electrode, ERCoCr-E rod or ERCCoCr-E wire
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Diameter(s) & Quantity - Diameter(s) and quantity in kg
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Packaging Preference - Hermetically sealed cans, vacuum-sealed, spools
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Required Third-Party Approvals - DNV, ABS, Bureau Veritas, Lloyds
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Test Certificate Requirements - MTC 3.1 per EN 10204 is supplied as standard
- Delivery Location - Delivery location in India
Nicorex Alloys can supply complete matching sets. ECoCr-E electrode + ERCoCr-E TIG rod + ERCCoCr-E MIG wire, ensuring consistent weld deposit chemistry across all welding processes on a single project.
Batch-tested stock available from the Mumbai warehouse.
Competitive pricing for project quantities.
Frequently Asked Questions
What is the price of ECoCr-E (Stellite 21) Welding Electrodes per Kg in India?
Why is ECoCr-E (Stellite 21) preferred over ECoCr-A (Stellite 6) for Duplex Stainless Steel Valve Hardfacing?
Can ECoCr-E weld deposits be machined after Hardfacing?
How does the Work-Hardening property of ECoCr-E benefit Valve seat applications?
ECoCr-E starts at 27–40 HRC after welding, but can work harden up to 48 HRC (550 HV) during metal-to-metal contact. In valve seats, repeated opening and closing cycles progressively harden the contact surface, improving galling resistance and sealing over the service life.