Introduction to C10200 Copper Alloy
C10200 is an oxygen-free, high-conductivity copper - the general-purpose member of the oxygen-free family and one of the most widely used engineering coppers in modern industry. It is specified to a minimum of 99.95 % copper with oxygen held at no more than 0.001 %, and it is supplied as rod, bar, plate, sheet, strip, tube, wire and foil.
C10200 earns its place because it combines three qualities that rarely appear together: very high electrical and thermal conductivity, excellent ductility and formability, and freedom from the oxygen that causes porosity and embrittlement during high-temperature processing. That combination is what makes it the default material for conductors, busbars and heat-exchanger components, and it is why designers return to it whenever a component must both carry current and be manufactured reliably.
Properties of C10200 Copper Alloy
High electrical conductivity is the defining characteristic. Residual impurity scattering in copper is low in this grade, so energy loss in transmission is minimised and electrical efficiency is maximised. Conductivity is typically quoted at about 100 % IACS or better in the annealed condition, with thermal conductivity around 385 W/m·K. In a conductor this means less resistive heating for a given cross-section, and in a heat exchanger it means a shorter or smaller exchanger for a given duty.
Corrosion resistance is the second pillar of the alloy's reputation. Copper develops a stable, protective surface film in air and water, and in wet or mildly aggressive environments the material resists attack that would degrade a less noble metal. In seawater and in chloride-bearing chemical environments the performance is good, although very high flow velocities combined with entrained solids can cause impingement attack, and strongly oxidising acids attack copper directly. The result of this corrosion stability is a long service life with little maintenance, which is why copper remains the standard for plumbing, heat transfer and electrical grounding.
Machinability and formability complete the picture. C10200 is soft and ductile, with excellent malleability and ductility; it can be stamped, deep drawn, forged, rolled, bent and formed into complex shapes without cracking. Tooling wears slowly, and because the material has no lead addition it is not a free-machining grade, so sharp tooling and generous clearances give the best surface finish.
| Property | Typical value |
|---|---|
| Composition | 99.95 % Cu minimum, oxygen 0.001 % maximum |
| Electrical conductivity | About 100 % IACS minimum (annealed) |
| Thermal conductivity | About 385 W/m·K at 20 °C |
| Density | 8.94 g/cm³ |
| Melting range | Approximately 1083 °C |
| Modulus of elasticity | About 117 GPa |
| Crystal structure | Face-centred cubic; non-magnetic |
| Common tempers | Annealed, quarter-hard, half-hard, hard, spring |
Mechanical strength depends strongly on temper rather than on composition: annealed material is soft and highly ductile, while cold-worked tempers raise the tensile strength substantially at the cost of elongation. The temper should therefore always be stated on the order.
Applications
The properties above translate into four broad application families.
Electrical industry: connectors, terminals, wires, busbars and bus conductors, transformer windings, and components in motors and generators that must carry high current without overheating. High conductivity and good thermal stability are the reasons C10200 is chosen here.
Electronics industry: printed circuit board conductors, plated-through-hole and connector stock, heat sinks and other components where reliable conduction and freedom from contamination matter. The material's stable conductivity keeps signal losses low and equipment life long.
Communications industry: components for high-frequency and fibre-optic systems, including connectors and adapters that require precise dimensions and stable electrical behaviour.
General engineering: seamless tube for plumbing, air conditioning and refrigeration, heat exchanger tube and plate, roofing and architectural sheet, and decorative and musical applications where workability and appearance are important.
In all of these uses, C10200 is chosen not for strength but for the combination of conduction, formability and cleanliness that no competing material delivers as economically.
Machining and Fabrication
The alloy is among the easiest copper grades to fabricate. Its ductility allows it to be drawn, deep drawn, spun, stamped and forged to tight tolerances, and its softness means tool wear is modest. Recommended practice is to use sharp, polished tooling with high rake angles, to take generous depths of cut, and to apply a good cutting fluid to control the build-up edge that soft copper tends to form. Because the material is gummy, surface finish is improved by increasing speed and feed rather than by reducing them.
For tube and sheet forming, the fully annealed temper gives the greatest ductility and should be specified when a severe form is required. Where dimensional stability after forming matters more than formability, a quarter-hard or half-hard temper will hold shape better. Intermediate anneals may be needed between successive deep-drawing operations, and because the material is oxygen-free those anneals can be carried out in a reducing atmosphere without the risk of hydrogen embrittlement.
Welding Properties
C10200 has good weldability. It is readily joined by gas tungsten arc welding (TIG), gas metal arc welding (MIG), resistance welding and brazing, and the joints produced have high strength and reliable gas-tightness. The absence of oxygen is a significant advantage here: oxygen-bearing copper tends to form steam pockets and porosity when welded or brazed in a reducing environment, whereas C10200 produces sound joints.
TIG welding is used for sheet, plate and tube joints, with direct current electrode negative, a matching deoxidised copper filler and a shielding gas of argon or a helium-argon mixture. Preheating is normally required only for thick sections.
MIG welding suits thicker plate and long runs, where its higher deposition rate is an advantage.
Resistance welding is used for light-gauge sheet and wire, taking advantage of the material's high thermal and electrical conductivity, which requires higher currents and shorter times than for steel.
Brazing and soldering are widely used for tube joints and electrical connections; the low oxygen content gives clean, sound joints without flux-related porosity.
The practical precautions are to clean the joint surfaces thoroughly, to remove every trace of oil and oxide, to use an inert shielding gas generously because copper conducts heat away rapidly from the weld pool, and to control heat input so that the grain structure in the heat-affected zone does not coarsen unnecessarily. Unlike leaded free-machining copper grades, C10200 does not liberate toxic fumes during welding, which makes it the preferred material where a component must be both machined and welded.
Inspection, Storage and Common Pitfalls
Buyers usually verify C10200 with a chemical analysis certificate, a conductivity or resistivity test, and a mechanical test in the temper that was ordered. Practical pitfalls worth guarding against are:
Substituting tough-pitch copper for oxygen-free material, which reintroduces porosity and embrittlement; the copper and oxygen limits should be confirmed on the certificate.
Handling contamination: copper surfaces are easily soiled and the resulting oxide interferes with brazing and welding.
Incorrect temper: a heavily cold-worked part that is then bent will crack, even though the alloy itself is ductile.
Galvanic coupling with more noble or less noble metals in wet service, which accelerates localised corrosion.
Excessive velocity with entrained solids in heat-exchanger tube, causing inlet-end impingement attack.
Store the material indoors, dry and protected from contact with steel, and keep it wrapped until it is used. Clean handling preserves both the appearance and the joining characteristics of the surface.
FAQ
Q: What is C10200 copper?
It is an oxygen-free, high-conductivity copper with a minimum of 99.95 % copper and no more than 0.001 % oxygen, supplied in rod, bar, plate, sheet, strip, tube, wire and foil forms.
Q: What is the electrical conductivity of C10200?
Approximately 100 % IACS or better in the annealed condition, with thermal conductivity around 385 W/m·K, which places it among the most conductive engineering metals.
Q: Is C10200 easy to weld?
Yes. It welds well by TIG, MIG and resistance welding, and it brazes and solders cleanly. The low oxygen content is the reason sound, gas-tight joints can be produced.
Q: Why is oxygen-free copper preferred over tough-pitch copper?
Because the absence of oxygen prevents hydrogen embrittlement during annealing in reducing atmospheres and prevents steam-pocket porosity during welding and brazing, giving more reliable fabrication.
Q: What is C10200 used for?
Electrical connectors, wires, busbars, motor and generator components, printed circuit and electronic parts, communications components, heat exchanger and plumbing tube, roofing sheet and decorative metalwork.
Q: Is C10200 magnetic?
No. Its face-centred cubic structure is non-magnetic, which is an advantage in instruments and equipment that are sensitive to stray magnetic fields.
Q: Which temper should be ordered?
Choose annealed for severe forming, and quarter-hard, half-hard, hard or spring temper where strength and dimensional stability after forming are more important than ductility.
Summary
C10200 copper alloy remains a reference material because it does the common jobs extremely well: it conducts current and heat efficiently, resists corrosion in normal service, forms and machines easily, and welds without porosity. Specify the temper and the oxygen limit explicitly, keep the surface clean, and avoid galvanic coupling; the alloy will then deliver the electrical and thermal performance and the long service life that industrial equipment demands.
