ERCOCR-B Filler Wire | ERCOCR-B Filler Wire CO12
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ERCoCr-B Filler Wire (Stellite® 12 / CO12 Cobalt Hardfacing Wire) Supplier in India
Nicorex Alloys is an ISO 9001 and ISO 14001 certified Mumbai-based importer, stockist, and supplier of cobalt hardfacing consumables. We supply ERCoCr-B cobalt hardfacing filler wire (sold commercially as Stellite 12 welding wire), Cobalt Alloy 12 TIG rod, or Co12 hardfacing rod as classified under AWS A5.21 / ASME SFA-5.21.
Alloy 12 is a Co-Cr-W bare rod and wire with a high carbon (1.4–2.0%) and tungsten (7.5–9.5%) content. The higher carbide volume places Stellite 12 as the intermediate hardfacing alloy. A two-layer GTAW deposit reaches HRC 45–51 (435–590 HV), and hot hardness holds to roughly 700°C (1292°F). The deposit contains 27–32% Cr, 7.5–9.5% W, and Co balance, giving it a high abrasion resistance while keeping reasonable impact tolerance. Rods come in 1.6–4.8 mm × 1000 mm lengths for GTAW (DCEN, 100% Argon, flat position); MIG/PTA wire spans 0.9–1.6 mm. OAW rods are stocked from 3.2–8.0 mm. UNS designation is R30012 (rod), W73012 (electrode), and W73042 (wire). F-Number is F-71.
Primary applications include saw tips for the timber industry, industrial cutting knives for carpet, plastics, and paper, high-pressure valve seats, engine exhaust valve hardfacing, glass mould plungers, and pinch rollers. Stellite 12 surfacing wire deposits can be machined with carbide tooling, though grinding is the preferred finishing method due to the higher hardness. ERCCoCr-B continuous wire for GMAW and PTA is also available. All shipments carry MTC 3.1 per EN 10204.
ERCoCr-B Cobalt 12 Filler Wire Technical Specifications
The technical specifications for ERCoCr-B filler wire, covering standards, processes, and available sizes, are listed below.
| Standard | AWS A5.21 / ASME SFA-5.21 (rod & wire); AWS A5.13 (electrode) |
|---|---|
| UNS Designation | R30012 (rod), W73012 (electrode), W73042 (wire) |
| Welding Processes | GTAW (TIG), OAW, PTA, GMAW (MIG) |
| Polarity / Shielding | (DCEN) / 100% Argon |
| Position | Flat (primarily) |
| Rod Diameters | 1.6, 2.4, 3.2, 4.0, 4.8 mm |
| Rod Length | 1000 mm (standard) |
| Wire Diameters (MIG/PTA) | 0.9, 1.2, 1.6 mm |
| OAW Rod Diameters | 3.2–8.0 mm |
| Deposit Hardness (2-layer GTAW) | HRC 45–51 (435–590 HV) |
| Melting Range | 1225–1280°C (2237–2336°F) |
| Hot Hardness Retention | Up to ~700°C (1292°F) |
| Density | 8.53 g/cm³ (0.308 lb/in³) |
AWS Classification Explained: ERCoCr-B (Stellite 12 / Co12)
The AWS A5.21 designation ERCoCr-B breaks down as follows:
| Prefix / Suffix | Meaning |
|---|---|
| ER | Electrode or Rod — bare filler metal for GTAW or OAW |
| Co | Cobalt — base metal of the alloy matrix |
| Cr | Chromium — primary alloying element for oxidation and corrosion resistance |
| -B | Composition Group B — Stellite 12 chemistry (higher C + W than Group A) |
ERCCoCr-B is the continuous wire variant for GMAW and PTA. ECoCr-B (AWS A5.13) is the coated SMAW electrode. The suffix family across cobalt hardfacing alloys is: -A (Stellite 6 / Co6), -B (Stellite 12 / Co12), -C (Stellite 1 / Co1), and -E (Stellite 21 / Co21). Group B differs from Group A by its higher carbon (1.4–2.0% vs 0.9–1.4%) and tungsten (7.5–9.5% vs 3–6%), producing a denser carbide network with greater abrasion resistance.
Chemical Composition of ERCoCr-B Weld Deposit (%)
The undiluted weld deposit composition of ERCoCr-B per AWS A5.21 is given below. All values are for the deposit; actual overlay chemistry varies with dilution from the base metal.
| Specification | Cobalt (Co) | Chromium (Cr) | Tungsten (W) | Carbon (C) | Nickel (Ni) | Iron (Fe) | Molybdenum (Mo) | Silicon (Si) | Manganese (Mn) |
|---|---|---|---|---|---|---|---|---|---|
| AWS A5.21 Req. (%) | Balance | 27.0–32.0 | 7.0–9.5 | 1.2–1.7 | 3.0 max | 3.0 max | 1.0 max | 2.0 max | 1.0 max |
Compared to ERCoCr-A, Stellite 12’s higher carbon and tungsten produce roughly 16% carbide volume fraction vs 13% for Stellite 6. That extra carbide density drives the higher abrasion and erosion resistance.
Deposit Hardness and Mechanical Properties of Stellite 12 (ERCoCr-B)
The deposit hardness and mechanical properties of ERCoCr-B overlay vary by process and number of layers, as shown below.
| Specification | Hardness, 2-layer GTAW | Hardness, Single Layer (diluted) | Hardness, OAW Deposit | Tensile Strength (typical UTS) | Elongation | Hot Hardness Retention |
|---|---|---|---|---|---|---|
| Typical Value | HRC 45–51 (435–590 HV) | HRC 35–42 | HRC 42–48 | ~740 MPa (~107 ksi) | <1% | Useful to ~700°C (1292°F) |
Co12 retains useful hardness roughly 200°C higher than Stellite 6 (~500°C). Finishing is by grinding only in most cases; carbide machining is possible, but difficult and produces high tool wear. That finishing constraint is a key cost factor when comparing Stellite 12 to Stellite 6.
Base Metal Compatibility for ERCoCr-B (Stellite 12) Hardfacing Overlay
ERCoCr-B can be deposited on any weldable steel, but it’s more crack-sensitive than ERCoCr-A due to higher carbon and carbide content. Preheating is essential. The table below gives recommended preheat ranges by substrate.
| Base Metal | Grade | ASME P-No. | Notes |
|---|---|---|---|
| Carbon Steel | A106 Gr.B / A516 Gr.70 | P1 | Preheat 250–350°C; slow cooling under insulation is mandatory |
| Cr-Mo Steel | P5 / P11 / P22 | P5 / P4 | Preheat 300–400°C; post-weld stress relief at 595–650°C recommended |
| Martensitic Stainless Steel | 410 / 420 | P6 | Preheat 250–350°C; match preheat to carbon steel range |
| Austenitic Stainless Steel | 304 / 316 | P8 | Preheat 100–150°C; lowest preheat requirement, least crack risk |
Hardfacing qualification falls under ASME Section IX QW-216 with F-Number F-71. Check cracking (stress-relief cracking) is more likely than with Stellite 6. Stringer beads and controlled interpass below 400°C reduce crack risk.
Recommended Welding Parameters for ERCoCr-B Cobalt 12 Hardfacing
Use a lower current than ERCoCr-A to reduce dilution and cracking. GTAW parameters for ERCoCr-B with 100% Argon shielding (DCEN, flat position) are given below.
| Rod Diameter (mm) | Current Range (A) | Process |
|---|---|---|
| 1.6 | 50–80 | GTAW |
| 2.4 | 70–110 | GTAW |
| 3.2 | 85–130 | GTAW |
| 4.0 | 110–150 | GTAW |
| 0.9–1.6 (wire) | 100–180 | PTA / GMAW |
OAW: use a neutral to slightly reducing flame with a higher preheat than Co6. GMAW shielding must be 100% Argon only (no CO₂). Slow cooling under insulation after welding is essential for all processes.
Key Wear Properties of ERCoCr-B (Stellite 12) Overlay
Five properties define where Stellite 12 outperforms Stellite 6 and where it falls short of Stellite 1:
- Higher abrasion resistance than Stellite 6: ~16% carbide volume vs ~13%, giving better low-angle erosion and severe sliding wear performance.
- Hot hardness to 700°C: roughly 200°C higher than Co6, critical for exhaust valve hardfacing and high-temperature cutting tools.
- Intermediate crack sensitivity: more prone to check cracking than Co6 but far less than Co1. Manageable with proper preheat and slow cooling.
- Cutting tool applications: the defining use case: industrial knives for carpet, plastics, paper, synthetic fibres, and saw tips in the timber industry.
- Machinable with difficulty: unlike Stellite 1, ERCoCr-B deposits can be machined with carbide tooling, though grinding remains preferred.
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Industrial Hardfacing Applications of ERCoCr-B Stellite 12 Filler Wire
Co12 hardfacing wire serves five core industries where abrasion, heat, and corrosion act together on component surfaces.
- Circular saw tips, band saw teeth, chipper knives, and debarker blades.
- Gate valve seats, where Stellite 6 wears too fast, high-pressure control valve trim, pump vanes, and bearing bushes.
- Exhaust valve seat inserts and face hardfacing for diesel and gas engines.
- Industrial knives for carpet, plastics, paper, and synthetic fibres. Narrow-neck glass mould plungers. Beverage industry control plates.
- Pinch rollers in steel mills and rotor blade edge hardfacing where moderate impact and high abrasion combine at elevated temperatures.
Storage and Handling of ERCoCr-B Cobalt 12 Filler Wire
ERCoCr-B is a bare wire product. No rebaking is required. Store in a clean, dry environment. Handle with gloves to prevent iron and moisture contamination on the rod surface. Co12 rods are more brittle than Co6 rods because of the higher carbide content; handle with extra care to prevent rod breakage during transport and feeding.
Available Forms, Diameters and Packaging of ERCoCr-B Stellite 12 Wire
ERCoCr-B filler wire is stocked in the forms and packaging listed below.
| Form | Diameters | Packaging |
|---|---|---|
| TIG Bare Cast Rods | 1.6, 2.4, 3.2, 4.0, 4.8 mm × 1000 mm | 2.5 kg or 5 kg plastic tubes |
| OAW Rods | 3.2–8.0 mm | 5 kg tubes |
| MIG / PTA Continuous Wire | 0.9, 1.2, 1.6 mm | Spools (various weights) |
| Powder (PTA / HVOF) | Various mesh sizes | Sealed containers |
How to Order ERCoCr-B Cobalt 12 Filler Wire from Nicorex Alloys
To order cobalt 12 bare rod or wire, provide the following details for an accurate quotation within 24 hours:
- AWS Classification: ERCoCr-B per AWS A5.21 / ASME SFA-5.21
- Product form: bare cast rod (GTAW/OAW) or continuous wire (GMAW/PTA)
- Diameter(s) required: typically 3.2, 4.0, 4.8 mm (1/8″, 5/32″, 3/16″)
- Rod length: 305 mm (12″) or 610 mm (24″)
- Quantity in kg
- Target deposit hardness: confirm ~HRC 47–51 expected
- Number of overlay layers and base metal grade
- Testing requirements: deposit hardness test, chemical analysis, PMI
- Certification: MTC 3.1 per EN 10204 (standard)
- Packaging preference and delivery address/timeline
Frequently Asked Questions
What is the Price of ERCoCr-B (Stellite 12 / Co12) Cobalt Filler Wire per Kg in India?
Indian market prices typically range from ₹4,500 to ₹8,500 per kg, depending on diameter, form, quantity, and current cobalt market rates. Contact Nicorex Alloys for the latest pricing.
Why is Stellite 12 Preferred over Stellite 6 for Saw Tip Hardfacing?
Higher carbon (1.4–2.0% vs 0.9–1.4%) and tungsten (7.5–9.5% vs 3–6%) produce ~16% carbide volume vs ~13%. That gives better abrasion resistance for timber cutting, where low-angle erosion from wood fibres and embedded grit is the dominant wear mechanism.
Can ERCoCr-B Deposits be Machined with Carbide Tooling?
Yes, but with significant difficulty. Unlike ERCoCr-C (Stellite 1), which requires grinding only, Co12 deposits can be machined with carbide tools. Grinding remains the preferred finishing method due to HRC 45–51 hardness and rapid tool wear.
What is the Maximum Service Temperature for ERCoCr-B (Stellite 12) Hardfacing?
Stellite 12 retains useful hardness to roughly 700°C (1292°F). This is about 200°C higher than Stellite 6 (500°C). Higher tungsten promotes thermally stable carbide phases. Co12 is preferred for engine exhaust valve hardfacing above 500°C.
Is ERCoCr-B More Prone to Cracking than ERCoCr-A During Hardfacing?
Yes. Higher carbon and carbide content make Co12 more susceptible to check cracking. Higher preheat (250–400°C vs 200–300°C for Co6), stringer beads, and slow cooling under insulation are essential. Check cracking is generally cosmetic and accepted by most hardfacing specifications.
Can ERCoCr-B be used against ERCoCr-A in a Mated Valve Seat Application?
Yes. Stellite 12 running against Stellite 6 is a common valve trim combination. The harder Co12 surface sits on the higher-wear component (typically the seat), while Co6 on the gate or disc provides impact tolerance. Co12 can also run self-mated.
Does Nicorex Alloys Stock ERCoCr-B in both Rod and Continuous Wire Form?
Yes. We stock ERCoCr-B bare rods (1.6–4.8 mm for GTAW and OAW) and ERCCoCr-B continuous wire (0.9–1.6 mm for GMAW and PTA). Matching ECoCr-B electrodes (AWS A5.13) are also available. Complete Co12 consumable sets ship from a single source with MTC 3.1.
When not to use ERCoCr-B (Stellite 12) Cobalt Filler Wire?
Don’t use Co12 where good impact or cavitation resistance is the priority; choose ERCoCr-A (Stellite 6) instead. Don’t use it where extreme abrasion demands Stellite 1 (ERCoCr-C, HRC 48–63). ERCoCr-B is a hardfacing overlay consumable, not a structural joining filler.