AWS Class ERCu MIG & TIG
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ERCu Deoxidised Copper TIG & MIG Welding Wire Supplier in India
Nicorex Alloys is an ISO 9001 / ISO 14001 certified supplier and stockist of ERCu deoxidised copper welding wire, based in Mumbai, India. We provide these welding wires as classified under AWS A5.7 / ASME SFA-5.7 with UNS C18900 (CDA 189).
ERCu is the only pure copper filler wire in the AWS A5.7 family. It keeps electrical conductivity close to the base metal because it contains at least 98.0% minimum Cu+Ag, with small amounts of phosphorus, silicon, tin and manganese as deoxidisers. These deoxidisers remove oxygen from the weld pool, forming harmless slag instead of gas pores, which are common in tough-pitch copper welds. ERCu gives dense, sound welds with a tensile strength of about 200 MPa (29,000 psi), yield strength of 55 MPa (8,000 psi), and 29% elongation. It has a solidus temperature of 1020°C and a liquidus of 1050°C, with a density of 8.9 g/cm³. ERCu TIG rods and MIG wires are used with GTAW (DCEN) and GMAW (DCEP, spray transfer) using argon or argon & helium gas.
Preheat is the most important factor when welding copper. Copper conducts heat at about 401 W/m·K, nearly 10 times more than steel. Without enough preheat, the weld will not fuse properly. ERCu wire is available as TIG rods from 0.9 to 4.8 mm and MIG wires from 0.8 to 3.2 mm. Typical uses include bus bar fabrication, conductor roll overlay, billet mould repair, copper pipe welding, and copper overlay on steel. Every batch is supplied with an MTC 3.1 to EN 10204.
ERCu Deoxidised Copper Welding Wire Specifications
Here are the key specifications for ERCu deoxidised copper welding wire, including classification, sizes, welding processes, polarity, shielding gas and product forms.
| AWS Specification | ERCu per AWS A5.7 / A5.7M |
|---|---|
| UNS Designation | C18900 (CDA 189) |
| Welding Processes | GTAW (TIG), GMAW (MIG) |
| Polarity | (GTAW): DCEN (electrode negative) (GMAW): DCEP (electrode positive), spray transfer |
| Shielding Gas | (Thin Sections): 100% Argon (Thick Sections): 75% He / 25% Ar or 100% Helium |
| TIG Rod Diameters | 0.9, 1.2, 1.6, 2.4, 3.2, 4.0, 4.8 mm |
| TIG Rod Length | 914 mm (36 in) |
| MIG Wire Diameters | 0.8, 0.9, 1.2, 1.6, 2.4, 3.2 mm |
| Spool / Drum | D200, D300, 12 in (30 lb), drums |
| Welding Positions | All positions |
What Does ERCu Mean? - AWS A5.7 Classification Explained
The following is a breakdown of each character of ERCu classified by AWS A5.7.
| Parameter | Recommended Practice | Feature / Rationale |
|---|---|---|
| E (Electrode) | Used as a consumable in GMAW (MIG) | Designed for continuous feed through a welding gun. |
| R (Rod) | Used as a filler in GTAW (TIG) | Suitable for hand-fed applications or oxy-fuel welding. |
| Cu (Copper) | 98%+ Copper content | Indicates the primary element: “pure” deoxidised copper. |
Weld Deposit Chemical Composition of ERCu
The values below show the typical chemical composition of ERCu weld deposits as per AWS A5.7, including copper and minor alloying elements.
| Specification | Copper + Silver (Cu+Ag) | Tin (Sn) | Manganese (Mn) | Phosphorus (P) | Silicon (Si) | Lead (Pb) | Other Elements (total) |
|---|---|---|---|---|---|---|---|
| AWS A5.7 Req. (%) | 98.0 min | 1.00 max | 0.50 max | 0.15 max | 0.50 max | 0.02 max | 0.50 max |
| Typical Deposit (%) | Balance | — | 0.45 | — | — | 0.0005 | — |
Phosphorus removes dissolved oxygen (Cu₂O) by turning it into P₂O₅ slag, which helps prevent hydrogen embrittlement. Silicon makes the weld pool flow more smoothly. Lead is limited to a maximum of 0.02%, because even tiny amounts can cause hot cracking.
All-Weld-Metal Mechanical Properties of ERCu
The values below show typical mechanical properties of ERCu weld metal, including its strength, elongation, hardness and more.
| Specification | Tensile Strength | Yield Strength (0.2% Offset) | Elongation (% in 50 mm) | Reduction of Area | Hardness |
|---|---|---|---|---|---|
| Typical Value | 200 MPa (29,000 psi) | 55 MPa (8,000 psi) | 29% | 45% | ~60 HBW |
ERCu welds are made to be soft. Their tensile strength of 200 MPa is only about 40% of mild steel. The main purpose of ERCu is to give high electrical conductivity and a good colour match, not high strength.
Base Metal Compatibility for ERCu Deoxidised Copper Wire
ERCu deoxidised copper wire is compatible with various copper grades and select steels, ensuring reliable weldability and conductivity for different applications.
| Base Metal | Grade | ASME P-No. | Notes |
|---|---|---|---|
| Phosphorus-deoxidised copper (DHP) | C12200 | P31 | Primary base metal; best weldability. Excellent compatibility. |
| Phosphorus-deoxidised low-P copper (DLP) | C12000 | P31 | Excellent compatibility. Lower phosphorus content yields higher electrical conductivity. |
| Oxygen-free copper (OF) | C10100, C10200 | P31 | Good compatibility. No dissolved oxygen; minimal porosity risk. |
| Electrolytic tough pitch copper (ETP) | C11000 | P31 | Fair compatibility. ~0.04% oxygen present as Cu₂O; elevated porosity risk. |
| Galvanised steel | — | P1 | Joining only (dissimilar metal). Low-strength joints (~200 MPa); zinc fume precautions required. |
| Mild steel | A36 / A105 | P1 | Overlay only. Copper deposited for corrosion resistance; not a structural weld. |
Do not use ERCu on free‑machining coppers with tellurium (C14500) or sulphur (C14700), because this can cause severe hot cracking.
Recommended TIG and MIG Welding Parameters for ERCu
These recommended TIG and MIG settings for ERCu help keep the arc stable, achieve good fusion and maintain conductivity on different copper thicknesses.
GTAW (TIG) Parameters — DCEN, EWTh-2 Tungsten
| Thickness | Gas | Filler Ø | Preheat | Amps |
|---|---|---|---|---|
| 0.3–0.8 mm | Argon | None | Nil | 15–60 A |
| 1.0–2.0 mm | Argon | 1.6 mm | Nil | 40–170 A |
| 2.0–5.0 mm | Argon | 2.4–3.2 mm | 50°C | 100–300 A |
| 6.0 mm | Argon | 3.2 mm | 100°C | 250–375 A |
| 10.0 mm | Argon | 3.2 mm | 250°C | 300–375 A |
| 12.0 mm | Argon | 3.2 mm | 250°C | 350–420 A |
| 16.0 mm | Argon | 3.2 mm | 250°C | 400–475 A |
GMAW (MIG) Parameters — DCEP, Spray Transfer
| Thickness | Wire Ø | Preheat | Amps | Volts | Gas Flow |
|---|---|---|---|---|---|
| 1.6 mm | 0.9 mm | 75°C | 150–200 A | 21–26 V | 10–15 L/min |
| 3.0 mm | 1.2 mm | 75°C | 150–220 A | 22–28 V | 10–15 L/min |
| 6.0 mm | 1.2 mm | 75°C | 180–250 A | 22–28 V | 10–15 L/min |
| 6.0 mm | 1.6 mm | 100°C | 160–280 A | 28–30 V | 10–15 L/min |
| 10 mm | 1.6 mm | 250°C | 250–320 A | 28–30 V | 15–20 L/min |
| 12 mm | 1.6 mm | 250°C | 290–350 A | 29–32 V | 15–20 L/min |
| 16+ mm | 1.6 mm | 250°C | 320–380 A | 29–32 V | 15–25 L/min |
Use stringer beads and a forehand technique for GTAW, and use spray transfer for GMAW. Clean oxide between passes with a bronze wire brush. For thicknesses above 6 mm, switch to a 75% helium / 25% argon gas mix to improve penetration and reduce the required preheat by about 55°C.
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Industrial Applications of ERCu MIG & TIG
ERCu MIG and TIG filler wire is ideal for copper welds that must carry electricity or heat efficiently. It gives reliable welds with strong performance and minimal risk of porosity.
- Electrical bus bars: Weld bus bars, transformer links, and switchgear while keeping high conductivity and low heat buildup.
- Steel mill electrode holders: Repair and overlay copper electrode holders and conductor rolls in furnaces and continuous casters.
- Billet mould repair: Restore worn copper moulds so they transfer heat efficiently for proper casting solidification.
- Copper pipe and tanks: Join deoxidised copper pipes, fittings, and tanks for plumbing, HVAC, chemical and water systems.
- Heater element welding: Fabricate and repair copper heater elements used in heaters, heat exchangers and electric water heaters.
- Copper sculpture and architecture: Join or repair copper artworks, facades, roofs and trims with colour-matched, neat welds.
- Corrosion-resistant steel overlay: Apply copper overlays on steel for ductile, corrosion-resistant surfaces in mild chemicals and atmosphere.
Storage and Handling of ERCu Deoxidised Copper Wire
Store ERCu welding wire and rods at 15-35°C below 60% RH in a clean, dry area with moderate temperature and humidity. Because copper oxidises easily, keep products sealed and away from moisture, acids and ammonia vapours. If you see dark tarnish or greenish discolouration, clean the wire with acetone or a fine abrasive before welding to help prevent porosity.
Keep TIG rods in sealed tubes and protect MIG spools from dust and contaminants, checking both the wire and the contact tip regularly. Always handle with clean gloves, and avoid any contact with zinc, lead, sulphur or tellurium. Re-baking is not required, and shelf life is effectively unlimited if products are stored dry and sealed. Each batch is supplied with an MTC 3.1 to EN 10204.
Available Forms, Diameters and Packaging of ERCu Welding Filler Wire
ERCu welding filler wire comes in several forms, sizes, and packaging options, including TIG rods, MIG spools, and bulk drums.
| Form | Diameters | Packaging |
|---|---|---|
| TIG Rod (straight length) | 0.9, 1.2, 1.6, 2.4, 3.2, 4.0, 4.8 mm | 1 lb, 2 lb, 5 kg / 10 lb tubes — 914 mm (36 in) |
| MIG Spool | 0.8, 0.9, 1.2, 1.6 mm | D200 (5 kg), D300 (12.5 kg), 12 in spool (30 lb) |
| MIG Drum | 1.2, 1.6, 2.4 mm | Bulk drums for high-volume production |
All wire ships with MTC 3.1 per EN 10204 with chemical analysis and heat traceability.
How to Order AWS Class ERCu MIG & TIG from Nicorex Alloys
Specify the following details in your RFQ to place an order for ERCu MIG and TIG welding wire from Nicorex Alloys:
- AWS classification: ERCu per AWS A5.7
- Product form: TIG rod or MIG spool or drum
- Diameter (mm or inch)
- Quantity (kg or number of spools/tubes)
- Rod length (914 mm standard) or spool size (D200 / D300 / 12 in)
- Shielding gas requirement (100% Ar, 75He/25Ar, or 100% He)
- Base metal being welded (C12200, C11000, C10200)
- Third-party approvals required (CCS, DNV, BV, LR, NK, KR)
- Test certificate type: EN 10204 3.1 / 3.2
- Delivery destination (domestic/International)
Frequently Asked Questions
What is the difference between ERCu and ERCuSi-A for welding copper?
ERCu maintains very high electrical conductivity, ideal for bus bars. ERCuSi-A is stronger but less conductive. Use ERCu for conductivity, ERCuSi-A for higher strength.
What shielding gas should be used for TIG and MIG welding copper with ERCu?
Use 100% argon below 6 mm. Above 6 mm, use 75% helium / 25% argon or 100% helium. Never use CO₂ or Ar/CO₂.
Can ERCu be used to weld copper to mild steel?
Yes, but the joint has a low strength of about 200 MPa. Suitable for overlays and non-structural joints.
When should ERCu not be used for?
Do not use on tellurium or sulphur-bearing free-machining coppers, or for joints needing over 200 MPa, or radiographic-quality welds on ETP copper due to porosity risk.