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Copper Casting and Copper Machined Parts


Copper Casting and Copper Machined Parts

Copper Casting and Copper Machined Parts

Copper castings and precision-machined copper parts are manufactured from high-purity copper grades – electrolytic tough pitch (ETP), oxygen-free (OF), and phosphorus-deoxidized (DHP) – to deliver the highest electrical conductivity, thermal conductivity, and corrosion resistance available in any engineering metal. Electrical Accessories India manufactures copper castings and CNC-machined copper components for electrical OEMs, transformer manufacturers, switchgear manufacturers, busbar system builders, earthing system contractors, EPC contractors, power utilities, and industrial distributors. With electrical conductivity of 99–102% IACS, copper remains unmatched as the primary conductor material where current-carrying capacity, thermal dissipation, and long-term joint reliability define design performance. Our copper components are supplied to all major industrial sectors across India and exported to 30+ countries with full material traceability documentation.

Product Overview

Copper Grades and Purity Requirements

Electrical-grade copper used in castings and machined parts must maintain purity above 99.9% Cu to preserve conductivity above 100% IACS. The primary commercial copper grades are: Electrolytic Tough Pitch (ETP / C11000 / Cu-ETP / CW004A) – the most widely used electrical copper, manufactured by electrolytic refining to 99.9% minimum purity with controlled oxygen content (200–400 ppm) that improves casting characteristics; Oxygen-Free Copper (OFC / C10200 / Cu-OF / CW008A) – manufactured by induction melting under inert atmosphere or using special deoxidation, achieving <5 ppm oxygen content for superior hydrogen embrittlement resistance at elevated temperatures and enhanced weldability; Phosphorus-Deoxidized Copper (DHP / C12200 / Cu-DHP / CW024A) – deoxidized with phosphorus, sacrificing approximately 15% of conductivity for superior brazeability, weldability, and freedom from hydrogen embrittlement in hot-working. Electrical Accessories India sources certified copper rod and ingot from NALCO, Hindalco, and international cathode suppliers, verified by incoming spectrometric analysis for purity and trace element content before any production use.

Casting of Copper – Challenges and Solutions

Copper is significantly more challenging to cast than its alloys (brass, bronze) due to its high melting point (1083°C), high thermal conductivity causing rapid solidification, high dissolved oxygen and hydrogen solubility in the melt, and the tendency for oxide film formation. Electrical Accessories India uses induction furnace melting under a protective charcoal cover layer to minimize oxidation, combined with precise superheat control (1100–1150°C), controlled pouring velocity through bottom-pour ladles, and resin-bonded sand or permanent mould systems. For oxygen-sensitive applications, argon-shrouded pouring is used to prevent re-oxidation during transfer. Radiographic testing (RT) and ultrasonic testing (UT) on castings verify internal soundness before dispatch. Our copper castings achieve density within 2% of theoretical (8.89–8.94 g/cm³), confirming minimal gas porosity.

CNC Machining of Copper

Pure copper has a machinability rating of approximately 20% relative to free-cutting brass (= 100%), presenting challenges including built-up edge on cutting tools, work hardening, and tendency to smear at cutting edges. Electrical Accessories India uses dedicated copper machining cells with PCD (polycrystalline diamond) and sharp-edged uncoated carbide tooling, high cutting speeds with flood coolant, and optimized feed rates to achieve burr-free, accurate copper machined parts. Dimensional tolerances of ±0.02 mm and surface finishes of Ra 0.8 µm are standard on copper machined parts from bar stock. CNC turning centres (capacity up to 400 mm diameter), CNC machining centres, and multi-spindle automatic lathes are used for high-volume copper component production. Parts produced include: busbar end blocks, transformer terminal lugs, earthing clamps, cable compression lugs, bus duct tap-off connectors, heat sink blocks, waveguide flanges, and custom copper machined components to drawing.

Electrical Conductivity and Application Design

The electrical conductivity of pure copper (C11000 / ETP) is 100–101% IACS, establishing it as the reference standard against which all other conductor materials are measured. This conductivity translates directly to energy efficiency: a copper busbar carries 1.6× the current of an equivalent cross-section aluminium busbar, or achieves the same ampacity at 61% of the aluminium cross-section – enabling more compact electrical panel designs. In high-power applications (transformer windings, busbar systems, switchgear contacts), even small reductions in conductor resistance significantly reduce I²R losses over a 30-year equipment life. Copper’s high melting point (1083°C) combined with high thermal conductivity (400 W/m·K) ensures that fault current events do not cause sudden conductor failure, providing critical equipment protection time that aluminium’s lower melting point (660°C) cannot match. Electrical Accessories India supplies copper components dimensioned to customer specifications including cross-sectional area calculations for target ampacity ratings.

Thermal Management Applications

Copper’s thermal conductivity of 385–401 W/m·K – second only to silver among common engineering metals – makes copper castings and machined parts the preferred choice for heat sink bodies, cold plates, heat spreaders, induction heating susceptors, and high-power electronic module base plates. Electrical Accessories India manufactures CNC-machined copper cold plates with internal water channels (helical, serpentine, or pin-fin configurations) for power electronics cooling in railway traction drives, wind turbine converters, industrial UPS systems, and high-power LED arrays. Copper heat sink blocks for IGBT modules, thyristor stacks, and busbars are produced to ±0.05 mm flatness tolerance to ensure low thermal contact resistance with device mounting surfaces.

Earthing and Grounding Components

Copper’s resistance to corrosion in soil, combined with its high conductivity, makes it the preferred material for earthing system components: earth rods, earth plates, earthing clamps, bonding conductors, lightning protection down-conductors, and substation earth grid conductors. Electrical Accessories India supplies forged copper earthing clamps, cast copper earth terminal blocks, and machined copper bonding connectors for substations, industrial plants, telecommunications towers, and building earthing systems. All earthing copper components are manufactured from minimum 99.9% Cu (ETP or OF grade) per IS 191, IEC 62561, and BS 7430 requirements. Corrosion resistance in soil environments exceeds 50 years for buried copper earthing components, making the lifecycle cost significantly lower than equivalent steel or galvanized steel earth systems.

Brazing, Welding, and Joining of Copper Components

Copper machined parts supplied by Electrical Accessories India are produced with joining considerations built into the design: brazed joints use silver brazing alloys (AWS BcuP-2 to BcuP-6, 5–15% silver content), and TIG/MIG welding uses Cu-ETP or Cu-OF filler wire (AWS ERCu per A5.7). Copper-to-copper brazed assemblies achieve joint efficiencies of 95–100% of parent metal strength when correctly made. Electrical Accessories India also supplies assembled copper sub-components – brazed busbar joints, silver-brazed heat exchanger assemblies, and pressed-fit copper terminal assemblies – eliminating customer sub-assembly operations and improving electrical joint reliability through controlled brazing in a workshop environment.

Key Features

  • Electrical conductivity 100–102% IACS (ETP grade) – the benchmark conductor material
  • Thermal conductivity 385–401 W/m·K – ideal for heat sinks, cold plates, and thermal management
  • Available grades: Cu-ETP (C11000), Cu-OF (C10200), Cu-DHP (C12200), Cu-FRHC (C12000)
  • Casting processes: sand casting, permanent mould, investment casting, continuous casting
  • CNC machining to ±0.02 mm tolerance, Ra 0.8 µm surface finish
  • Compliant with IS 191, ASTM B152, BS EN 1173, DIN EN 13601, IEC 60228
  • Melting under protective atmosphere for oxygen-free and low-oxygen grades
  • Full material traceability: EN 10204 3.1 Mill certificates, spectrometric analysis
  • RoHS 3 and REACH compliant
  • Export certified: CE, SGS, BV third-party inspection available

Material Grades and International Equivalents

Grade India (IS) USA (ASTM/UNS) UK (BS EN) Germany (DIN) Europe (EN) Japan (JIS) ISO Cu min% O ppm Conductivity (%IACS)
ETP (Electrolytic Tough Pitch) IS 191 Cu-ETP C11000 / UNS C11000 BS EN 1173 CW004A DIN EN Cu-ETP EN CW004A JIS C1100 ISO Cu-ETP 99.90 200–400 100–101
OF (Oxygen-Free) IS 191 Cu-OF C10200 / UNS C10200 BS EN 1173 CW008A DIN EN Cu-OF EN CW008A JIS C1020 ISO Cu-OF 99.95 <5 101–102
OFE (Oxygen-Free Electronic) — C10100 / UNS C10100 — DIN EN Cu-OFE EN CW009A JIS C1011 ISO Cu-OFE 99.99 <2 101–102
DHP (Phosphorus Deoxidized) IS 191 Cu-DHP C12200 / UNS C12200 BS EN 1173 CW024A DIN EN Cu-DHP EN CW024A JIS C1220 ISO Cu-DHP 99.85 <10 85–90
FRHC (Fire Refined High Conductivity) IS 191 Cu-FRHC C12000 / UNS C12000 BS EN 1173 CW007A — EN CW007A — ISO Cu-FRHC 99.90 100–500 98–100
Chromium Copper — C18200 / UNS C18200 BS 2870 CC101 DIN CuCr1 EN CW105C JIS C1940 — 98.5 + Cr — 80–85
Beryllium Copper (Cast) — C82500 / UNS C82500 — DIN CuBe2 EN CC330G-equiv. — — 96.8 + Be — 17–22

Technical Specifications

Property Cu-ETP (C11000) Cu-OF (C10200) Cu-DHP (C12200) CuCr1 (C18200)
Density (g/cm³) 8.89 8.94 8.92 8.89
Tensile Strength (MPa) – Annealed 200–250 200–250 210–260 400–500
0.2% Yield Strength (MPa) 60–100 60–100 70–110 300–400
Elongation (%) – Annealed 40–50 40–55 35–50 15–25
Hardness (HB) – Annealed 40–60 40–60 45–65 100–140
Electrical Conductivity (%IACS) 100–101 101–102 85–90 80–85
Thermal Conductivity (W/m·K) 394 401 339 324
Melting Point (°C) 1083 1083 1083 1075
Max. Service Temp. (°C) 200 200 200 400
Machinability Rating (%) 20 20 20 20

Product Types and Variants

  • Sand Castings – Complex copper casting geometries, 0.1–200 kg
  • Permanent Mould Castings – High repeatability busbar end blocks, terminal bodies
  • Continuously Cast Bar, Rod, and Profile – Near-net-shape feedstock for machining
  • CNC Turned Parts – From copper rod/bar, ±0.02 mm tolerance
  • CNC Milled/Machined Blocks – Heat sink blocks, cold plates, busbar adapters
  • Forged and Machined Copper – High-density, void-free copper for critical electrical joints
  • Silver-Brazed Copper Assemblies – Multi-part assemblies brazed and pressure-tested

Applications in Industry

  • Electrical & Power: Busbar systems, transformer terminal blocks, switchgear contact fingers, earthing clamps, cable compression lugs, bus duct tap-off bodies, neutral links, circuit breaker contacts
  • Thermal Management: Heat sink blocks, cold plates for IGBT/thyristor stacks, induction heater coils, heat exchanger headers, copper cooling channels in welding equipment
  • Earthing & Lightning Protection: Earth terminal blocks, bonding connectors, lightning protection down-conductor clamps, substation earth grid connectors
  • Telecommunications: Waveguide flanges, RF connector bodies, coaxial connector shells, antenna feedthrough blocks
  • Chemical & Process: Copper reactor vessels, heat exchanger tube sheets, chemical plant fittings in non-oxidizing acid service
  • Defence & Aerospace: Copper commutator segments, slip ring bodies, high-frequency shielding components

Manufacturing Process

1. Raw Material: Electrolytic copper cathode (99.99% Cu) or certified copper rod verified by incoming spectrometric analysis. Oxygen content checked for OF-grade work.
2. Melting: Induction furnace under charcoal cover layer at 1100–1150°C. Argon shroud used for OF grades. Phosphor-copper deoxidizer added at controlled rate for DHP grades.
3. Casting: Sand or permanent mould at controlled pouring speed; continuous casting at controlled withdrawal and water-cooling rates for bar/tube production.
4. NDT: Radiographic testing (RT) on sand castings per ASTM E155; ultrasonic testing (UT) on continuous cast bar per ASTM E114.
5. Machining: PCD or sharp uncoated carbide tooling; high cutting speed, flood coolant, optimized chip management to prevent copper smearing.
6. Surface Finishing: Bright tin plating (5–15 µm, ASTM B545), electroless nickel plating (25 µm, ASTM B733), silver plating (5–20 µm, ASTM B700), passivation, or as-machined.
7. Pressure Testing: Cold plates and hollow assemblies hydrostatic pressure tested to 1.5× working pressure.
8. Inspection: Dimensional (CMM), conductivity check (eddy current method), surface finish measurement, visual inspection.

Quality Standards and Certifications

  • IS 191 – Indian Standard for Wrought Copper (Cu-ETP, Cu-OF, Cu-DHP)
  • ASTM B152 – Copper Sheet, Strip, Plate, and Rolled Bar
  • ASTM B187 – Copper Bus Bar, Rod, and Shapes
  • BS EN 1173 / EN 13601 – Copper and Copper Alloy Rod and Bar (CW004A, CW008A, CW024A)
  • IEC 60228 – Conductors of Insulated Cables (conductivity verification)
  • IEC 62561 – Lightning Protection System Components
  • BS 7430 – Code of Practice for Earthing
  • ISO 9001:2015 Quality Management System
  • RoHS 3 Directive 2015/863/EU compliant
  • REACH Regulation (EC) 1907/2006 compliant

Why Choose Electrical Accessories India

  • Certified High-Purity Copper: Only NALCO/Hindalco or imported cathode-origin copper used; purity verified before every production run
  • Complete Capability: Casting, forging, continuous casting, CNC machining, surface finishing, and assembly at one facility
  • Electrical Sector Expertise: Deep experience supplying transformer manufacturers, switchgear OEMs, and busbar system fabricators
  • Surface Finishing In-House: Tin, silver, nickel plating for copper electrical contacts without sub-contracting delays
  • Export Track Record: Supply to USA, UK, Germany, UAE, Australia, Singapore, South Africa with EN 10204 3.1 Mill certificates
  • Rapid Prototyping: From drawing to prototype copper machined part in 5–7 working days
  • Competitive Pricing: Direct manufacturer, no trading margin; copper LME-linked pricing on bulk orders

Frequently Asked Questions (FAQ)

Q1: What is the difference between Cu-ETP and Cu-OF copper?

Cu-ETP (C11000) is electrolytic tough pitch copper containing 200–400 ppm oxygen. It has 100–101% IACS conductivity and is the standard for most electrical applications. Cu-OF (C10200) is oxygen-free, produced under inert atmosphere, with <5 ppm oxygen. It has slightly higher conductivity (101–102% IACS) and is immune to hydrogen embrittlement when heated in reducing atmospheres – critical for brazing, annealing, and high-vacuum applications. For standard busbar and earthing use, Cu-ETP is specified. For winding wire, waveguides, and precision instruments, Cu-OF or Cu-OFE is preferred.

Q2: Why is copper harder to machine than brass?

Pure copper work-hardens rapidly during cutting, has high ductility causing smearing and built-up edge on tool faces, and produces long stringy chips that wrap around tooling. Brass (CuZn39Pb3) contains lead which acts as a chip-breaker and internal lubricant. Electrical Accessories India uses PCD tooling, high rake angles, high cutting speeds, flood coolant, and optimized feed rates to machine copper to high tolerances and good surface finishes – techniques developed through extensive production experience.

Q3: Can copper castings achieve the same conductivity as wrought copper?

Cast copper typically achieves 95–99% IACS, slightly below wrought copper (100–102% IACS), due to the dendritic microstructure of castings versus the work-refined grain structure of rolled or drawn copper. For busbar and high-conductivity applications requiring 100% IACS, machined parts from continuously cast or rolled copper bar are preferred over sand castings. Where complex geometry justifies casting, the 1–5% conductivity reduction is acceptable in most engineering applications.

Q4: What surface treatments are available for copper machined parts?

Available surface treatments: bright tin plating (5–15 µm, ASTM B545) – most common for electrical terminals and lugs for corrosion protection and solderability; silver plating (5–20 µm, ASTM B700) – for high-current electrical contacts and busbar joints to reduce contact resistance; electroless nickel plating (25 µm, ASTM B733) – for dimensional uniformity and corrosion resistance on complex geometry; hard chrome plating (15–50 µm) – for wear resistance on copper forming tools; and passivation/chemical brightening for cosmetic finish without plating.

Q5: What is the maximum size copper casting you can produce?

Sand castings up to 200 kg. Permanent mould castings up to 50 kg. Continuous cast bar up to 250 mm diameter. For larger copper components (transformer connection plates, large heat exchanger tube sheets), we machine from continuous cast or forged copper plate in sizes up to 1200 × 600 mm.

Q6: Do you supply copper parts for transformer windings?

We supply copper components associated with transformer construction: terminal stud assemblies, bushing terminal rods and caps, on-load tap changer (OLTC) contact fingers, neutral link blocks, tank earthing lugs, and copper press-fit inserts. Transformer winding strip and wire (continuously drawn) is available from our associated suppliers.

Q7: Are your copper parts compliant with IEC 60228 conductor requirements?

Yes. Our Cu-ETP and Cu-OF machined parts for use as current-carrying conductors meet the conductivity requirements of IEC 60228 Class 1 and Class 2 conductors (minimum 100% IACS at 20°C). Conductivity test reports using the eddy current method (per ASTM E1004) are available with each order.

Q8: Can you supply silver-plated copper busbars and connector blocks?

Yes. Electrical Accessories India supplies silver-plated (5–20 µm) copper busbars, connector blocks, and contact fingers. Silver plating reduces contact resistance at bolted joints by up to 40% compared to bare copper, and significantly improves oxidation resistance at elevated temperatures in switchgear. Silver plating is applied by electrodeposition per ASTM B700 Grade N (normal) or Grade S (supplementary tarnish treatment).

Q9: What documentation is supplied with copper orders?

Standard documentation: Chemical Analysis Certificate (spectrometric, confirming Cu purity and trace elements), Conductivity Test Certificate (eddy current method, %IACS), Dimensional Inspection Report, EN 10204 2.2 or 3.1 Mill Certificate. Optional: REACH/RoHS Declaration, Silver/Tin Plating thickness certificate (XRF measurement), Pressure test certificate for hollow assemblies, and third-party inspection reports (SGS, BV, TÜV).

Q10: How do I specify a copper machined part order?

Provide: drawing (PDF/DXF/STEP), copper grade required (Cu-ETP / Cu-OF / Cu-DHP or UNS/EN designation), quantity, surface treatment, dimensional tolerances, and delivery destination. For castings, specify weight, critical dimensions, and any NDT requirements. Our engineering team reviews DFM and provides a technical proposal within 24 hours, including recommendation on casting vs. bar machining based on geometry and quantity.

Equivalent Terms – Multilingual Reference

Language Term 1 Term 2 Term 3
Spanish Fundición de cobre puro Piezas mecanizadas de cobre Componentes de cobre electrolítico
Russian Медное литьё Обработанные детали из меди Компоненты из электролитической меди
French Pièces moulées en cuivre pur Cuivre usiné de précision Composants en cuivre électrolytique
Portuguese Fundição em cobre puro Peças usinadas em cobre Componentes de cobre eletrolítico
Italian Fusione in rame puro Parti lavorate in rame Componenti in rame elettrolitico

Related Products and Linked Terms

Request a Quote

Electrical Accessories India engineers respond to all copper casting and machined parts enquiries within 24 hours. Submit your drawing (PDF/DXF/STEP), copper grade, quantity, surface treatment, tolerance requirements, and delivery destination for a complete technical and commercial proposal. We supply prototype quantities through to high-volume production, with full EN 10204 3.1 Mill certificate and conductivity test documentation. Export to 30+ countries with complete shipping documentation.

Contact us today to discuss your copper casting and machined parts requirements – from single prototype to mass production.

Indicative Pricing

Copper Items: US$ 15.80 per kilogram, CIF US Port

Prices are indicative and subject to change based on quantity, specification, alloy grade, and market conditions. Contact us with your RFQ for a firm quotation.