AWS Class ECuNi Welding Electrodes

AWS Class ECuNi Coated Electrode Supplier in Mumbai, India

Name: AWS Class ECuNi Welding Electrodes
Brand: Nicorex Alloys

Nicorex Alloys is an ISO 9001 and ISO 14001 certified importer, stockist, and supplier of ECuNi copper-nickel coated electrodes based in Mumbai, India. AWS A5.6 / ASME SFA 5.6 (UNS W60715) and ASME Section IX code F-34 apply. ECuNi is the only copper alloy. SMAW electrode classified under AWS A5.6 that deposits a 70Cu-30Ni weld metal composition matched to C71500, which is the most widely used marine alloy.

ECuNi deposits (~67% Cu, 30% Ni) provide the galvanic match needed to protect Cu-Ni alloys from seawater. ECuNi Coated Electrode stick electrodes have anti-biofouling, saltwater corrosion resistance, and galvanic compatibility with copper-nickel pipe systems. Monel 187, MONEL Welding Electrode 187, and CuNi 70/30 welding rod are alternate names for this copper-nickel SMAW electrode. The weld deposit contains approximately 67% Cu, 30% Ni, 1.5% Mn, and 0.5% Fe with Ti deoxidation. Typical tensile strength reaches 380 MPa (55 ksi) with 28% elongation. The mineral-coated electrode operates on DCEP polarity in all positions with smaller diameters.

Available sizes include 2.4, 3.2, 4.0, and 4.8 mm. ECuNi welds 70/30 Cu-Ni (C71500) to itself, to 80/20 and 90/10 (C70600) alloys, and dissimilar joints to Monel 400 or Nickel 200. Every batch ships, plus MTC 3.1 per EN 10204. Industries where this alloy is applicable include naval shipbuilding, desalination, offshore oil and gas, and coastal power generation.

ECuNi Coated Electrode Specifications

Refer to the table below: ECuNi follows the AWS A5.6 copper standard, not the AWS A5.11 nickel standard, and uses copper-based core wire.

AWS Classification	ECuNi
ASME SFA Specification	SFA 5.6
UNS Number	W60715
ASME Section IX F-Number	F-34
Welding Process	SMAW (Shielded Metal Arc Welding)
Electrode Coating	Mineral type
Current/Polarity	DCEP (DC Electrode Positive)
Welding Positions	All positions (smaller diameters); flat and horizontal (larger diameters)
Available Diameters	2.4, 2.5, 3.2, 4.0, 4.8, 5.0 mm (3/32″, 1/8″, 5/32″, 3/16″)
Electrode Length	305 mm (12″) for 2.4 mm; 356 mm (14″) for 3.2 mm and above
Maximum Interpass Temperature	100°C (212°F)
Packaging	Hermetically sealed canisters, 10 lbs (4.54 kg) / 5 kg tubes

Weld Deposit Chemical Composition of ECuNi

Refer to the following table for ECuNi as per AWS A5.6, all-weld-metal chemical composition, representing deposit values rather than base metal chemistry.

Element	Cu + Ag	Ni + Co	Mn	Fe	Si	Ti	C	Pb	P	S	Other
AWS A5.6 Range (wt.%)	Remainder (~65–67)	29.0–33.0	1.0–2.5	0.40-0.75	0.50 max	0.50 max	0.05 max	0.02 max	0.02 max	0.015 max	0.50 max

Iron content is an essential element of this alloy. Fe (0.40–0.75%) is carefully regulated, as below 0.40%, seawater corrosion resistance decreases, and base metal dilution beyond 10% causes hot cracking and dealloying. Manganese 1.0-2.5% deoxidizes the weld pool and scavenges sulfur, preventing copper-nickel deposit porosity.

All-Weld-Metal Mechanical Properties of ECuNi

All-weld-metal mechanical properties per AWS A5.6 are listed below. These are weld deposit properties, not base metal values.

Property	Tensile Strength	Yield Strength (0.2% offset)	Elongation (% in 4D)	Charpy V-Notch Impact	Hardness
Typical Value	380 MPa (55 ksi)	260 MPa (38 ksi)	28%	Not specified	~100–130 HB
AWS A5.6 Minimum	350 MPa (50 ksi)	Not specified	20%	Not specified	Not specified

ECuNi provides a composition-matched, non-overmatching filler with 380 MPa strength. Its ductile deposit ensures saltwater fatigue performance in vibrating marine pipes. We prioritise galvanic compatibility over higher ENiCu-7 tensile strength.

Base Metal Compatibility and P-Number Matrix for ECuNi

ECuNi joins similar copper-nickel grades (all ASME P-34) and selected dissimilar metals. The table below lists approved configurations and restrictions.

Base Metal A	P-No.	Base Metal B	P-No.	Notes
C71500 (70/30)	P-34	C71500 (70/30)	P-34	Primary application
C71000 (80/20)	P-34	C71000 (80/20)	P-34	Similar joint
C70600 (90/10)	P-34	C70600 (90/10)	P-34	Similar joint
C71500 (70/30)	P-34	C70600 (90/10)	P-34	Dissimilar Cu-Ni grades
Cu-Ni alloy	P-34	Monel 400	P-42	ECuNi or ENiCu-7
Cu-Ni alloy	P-34	Nickel 200	P-41	ECuNi acceptable
Cu-Ni clad steel	P-34	Carbon steel	P-1	Barrier layer required -never direct

ASME Section IX Table QW-432 F-Number is F-34. ECuNi deposits don’t have an A-Number since QW-442 only covers iron- and nickel-base deposits. Apply an ENi-1 or ENiCu-7 barrier layer before welding ECuNi to carbon steel (P-1), stainless steel (P-8), or low-alloy steel (P-3, P-4).

Recommended Welding Parameters for ECuNi Electrode

Diameter-specific parameters with position guidance are listed below. Consult the manufacturer’s technical data sheet for the specific electrode.

Diameter (mm)	Diameter (in)	Length (mm)	Current (A)	Polarity	Position
2.4	3/32″	305	60–85	DCEP	All
3.2	1/8″	356	70–120	DCEP	All
4.0	5/32″	356	100–145	DCEP	Flat/Horizontal
4.8	3/16″	356	130–190	DCEP	Flat/Horizontal

Recommended maximum interpass temperature is 100°C (industry practice for Cu-Ni alloys).

Premium Industrial Materials

Get AWS Class ECuNi Welding Electrode at Competitive Prices

ISO Certified

Custom Sizes

Fast Delivery

Get a Quote

Marine & Industrial Welding Applications of ECuNi Electrodes

The following are the industrial applications of ECuNi Electrodes :

ECuNi welds C71500 and C70600 fire main, ballast, cooling water, condenser tube-to-tubesheet, valve bodies, hull fittings, and sea chests. Cu-Ni weld deposits resist barnacle and algae adhesion and chloride stress corrosion cracking in pipes that cannot be cleaned.
ECuNi SMAW consumables match C70600 and C71500 MSF distillation tubes. Use them for MSF brine heater, tubesheet, and seawater intake welds.
ECuNi welds offshore seawater lift pipes, firewater deluge systems, and produced water cooler tubes. ECuNi-welded is ideal for safety-critical firewater systems without non-metallic pipes.
Coastal power plants weld steam condenser tube-to-tubesheet and cooling water intake pipework using ECuNi. These deposits match base metal erosion-corrosion resistance, avoiding saltwater weld joint failure.
ECuNi welds copper-nickel clad steel plates for ship hulls, water boxes, and offshore projects.

Storage, Handling, and Re-Drying Procedures for ECuNi Electrodes

Nicorex Alloys supplies ECuNi in hermetically sealed canisters. No re-drying is needed for first use if the packaging is intact. For moisture-exposed electrodes, re-dry at 200–250°C (390–480°F) for 30–60 minutes. After opening, hold in an oven at 100–150°C. Maximum exposure outside the oven is 4 hours; re-dry a maximum of 3 times.

Use only stainless steel brushes and tools dedicated to copper-nickel work. Carbon steel contamination introduces iron into the weld zone, risking hot cracking and accelerated corrosion. Never reuse grinding discs from carbon steel work.

Available Sizes for ECuNi Alloy

Nicorex Alloys stocks all four diameters in factory-sealed hermetic canisters with full MTC documentation.

Diameter (mm)	Diameter (in)	Length
2.4	3/32″	305 mm (12″)
3.2	1/8″	356 mm (14″)
4.0	5/32″	356 mm (14″)
4.8	3/16″	356 mm (14″)

Slow and poor weaving fusion characterises CuNi weld pools. Arcs should be short to minimise copper porosity and oxidation. Hot shortness causes centreline cracking at interpass temperatures exceeding 100°C/212°F. Perform an argon back purge during pipe root passes to prevent oxidation.Do not use oxyacetylene.

Iron dilution warning: never weld ECuNi directly onto steel or exceed 10% iron in the deposit. For Cu-Ni clad steel, use ENi-1 or ENiCu-7 as the first barrier pass onto the steel side, then ECuNi for cover passes.

How to Order ECuNi (Monel 187) Copper-Nickel Electrodes from Nicorex Alloys

Please provide the following details to place an order for ECuNi (Monel 187) Copper-Nickel Electrodes from Nicorex Alloys

Electrode Type - SMAW Covered Electrode (ECuNi / Monel 187)
Size - 2.5mm / 3.2mm / 4.0mm (covered electrodes) — specify diameter and length
Current Type - DCEP (Electrode Positive) — specify diameter
Welding Position - All Positions (smaller diameters) / Downhand (larger diameters) — specify requirements
Material Grade - ECuNi / Monel 187 / UNS W60715 / AWS A5.6 / ASME SFA 5.6 / DIN 1733: S CuNi30Mn / W.Nr. 2.0838
Quantity - Number of cans / cartons or total weight in kg
Standard - AWS A5.6 / ASME SFA 5.6 (ECuNi), ASME Section IX F-No. 34
Documentation - MTC EN 10204 3.1/3.2, Chemical Composition Report, Mechanical Properties Report, TPI Certificate
Packaging - Hermetically sealed containers (10 lb / 4.54 kg), ISPM 15 compliant export cartons
Delivery Destination - Domestic / International (specify port of discharge or delivery address)

Frequently Asked Questions

What is the Price of ECuNi (Monel 187) Copper-Nickel Welding Electrode per kg in India?

Pricing depends on diameter, order quantity, and copper commodity rates. Cu-Ni electrodes are in the speciality tier above stainless steel consumables but typically below high-nickel types such as ENiCrMo. 3. Contact Nicorex Alloys for current per-kg pricing with stock confirmation.

What is the Difference Between ECuNi (AWS A5.6) and ENiCu-7 (AWS A5.11)?

According to the copper alloy standard (A5.6), ECuNi deposits a copper-rich weld metal (~67% Cu, 30% Ni). ENiCu-7 deposits nickel-rich weld metal (~65% Ni, 30% Cu) per nickel alloy standard (A5.11). ECNi and ENiCu-7 weld Cu-Ni alloys and Monel 400/K-500. In seawater, ECuNi is galvanically compatible with Cu-Ni base metals, while ENiCu-7 generates a noble weld bead that promotes corrosion.

Can ECuNi Weld Both 90/10 (C70600) and 70/30 (C71500) Copper-Nickel Alloys?

Yes. ECuNi is the standard filler for all Cu-Ni grades, which are 90/10 (C70600), 80/20 (C71000), and 70/30 (C71500). The 70/30 deposit overmatches lower-nickel grades in both corrosion resistance and strength. ECuNi also joins Cu-Ni alloys to Monel 400 or Nickel 200 in dissimilar configurations.

What Makes ECuNi Weld Deposits Resistant to Marine Biofouling?

The Cu-Ni weld surface releases copper ions that poison barnacles, algae, and tubeworms. Using a stainless steel or nickel-alloy filler instead makes the weld area more likely to attract fouling, which stops water flow and leads to corrosion under the non-copper deposit.

What ASME F-Number and P-Number Apply to ECuNi?

ECuNi is assigned F-34 per ASME Section IX Table QW-432. The base metals – C71500, C71000, and C70600 that carry P-34. ECuNi deposits do not receive an A-Number because QW-442 covers iron-base and nickel-base deposits only, not copper-base deposits.

What Interpass Temperature Limit Applies When Welding Cu-Ni with ECuNi?

Maximum interpass temperature is 100°C (212°F). Cu-Ni alloys are susceptible to hot shortness. Low-melting-point grain boundary phases remelt if the base metal temperature rises too high, causing intergranular cracking. This limit is stricter than nickel alloy welding, where the interpass is typically 150–200°C.