Definition and Grade Background of C10100 OFC Pipe
C10100 is oxygen-free electronic copper, also described as OFE or OFC, the highest-purity wrought copper grade in normal industrial supply. Copper content is 99.99% minimum and the residual oxygen is held to a maximum of 0.0005% (5 ppm), so the metal contains no copper oxide inclusions of the kind that are present in ordinary tough-pitch copper. The result is a material that combines the highest practical electrical and thermal conductivity with excellent ductility and immunity to hydrogen embrittlement.
Round pipe in this grade is used wherever conductivity, vacuum integrity or freedom from embrittlement decides the design: electrical conductors and bus systems, vacuum and microwave devices, and high-integrity process pipework. Tube and pipe are supplied to ASTM B111 for condenser and heat exchanger service and to the general seamless copper tube specifications such as ASTM B75 and ASTM B280, under temper designations described in ASTM B601.
Composition and Property Data
| Item | Value |
|---|---|
| Copper (Cu) | 99.99 % min |
| Oxygen (O) | 0.0005 % max |
| Electrical conductivity | Up to 101 % IACS (about 58.6 MS/m) |
| Thermal conductivity | Up to 391 W/(m·K) |
| Density | 8.94 g/cm³ |
| Melting point | 1083 °C |
| Tensile strength, annealed | Around 210 MPa typical |
| Elongation, annealed | 45 % or more |
The purity limits that matter most are the oxygen, sulphur, lead and zinc maxima, which are specified individually and are the reason this grade costs more than electrolytic tough pitch copper. Composition is covered by ASTM B170 for refinery shapes and by ASTM F68 for oxygen-free copper in unalloyed forms for electron devices.
Electrical and Thermal Performance
Because there are no oxide inclusions to scatter carriers and no dissolved oxygen to interfere with grain structure, C10100 delivers conductivity at the top of the copper range. Practical consequences for the designer are lower resistive loss in high-current conductors, minimal signal attenuation at high frequency, and a material that can be joined by brazing or welding into vacuum-tight assemblies.
Electrical conductors, bus bars and high-strength conductor wire where IACS rating is a contractual requirement.
Hollow conductors, wave guides and coaxial tubing in radio-frequency and microwave equipment.
Klystron, magnetron and microwave tube bodies, anodes and vacuum seals.
Cryogenic shunts and buswork, where stable resistance at low temperature is essential.
Heat sinks, induction coils and high-efficiency heat transfer components relying on 391 W/(m·K) thermal conductivity.
Corrosion, Vacuum and Embrittlement Behaviour
Oxygen-free copper does not suffer hydrogen embrittlement: in a reducing or hydrogen-bearing atmosphere at elevated temperature, ordinary tough-pitch copper can be damaged by steam generated at oxide inclusions, whereas C10100 remains sound. This is why the grade is standard for furnace brazing and for vacuum service. The metal is stable in dry air and in weakly acidic or alkaline media, and it is used in chemical pipework where high purity of the conveyed fluid matters as much as the corrosion rate. Like all unalloyed copper it should not be used with ammonia-bearing or strongly oxidising media without an engineering assessment.
Forming, Joining and Heat Treatment
The annealed O60 temper is used for bending, flaring and expansion; the hard-drawn tempers give higher strength for straight runs and machined parts.
Annealing is carried out in a protective or reducing atmosphere to preserve the oxygen-free condition and the clean, bright surface.
Tungsten inert gas welding, electron beam welding and furnace brazing in a protective atmosphere are the usual joining processes; filler and flux selection must suit pure copper.
Cold working raises strength and reduces conductivity slightly, so a final anneal is specified where the conductivity value is critical.
Surfaces should be kept free of iron contamination and chloride-bearing marking materials, which cause localised attack in service.
Inspection and Dimensional Verification
Purchasers normally require the heat analysis to confirm the purity limits, a conductivity check by the eddy-current or resistance method, tensile and elongation tests, and full dimensional inspection of outside diameter, wall thickness, eccentricity, ovality and length. For pipe destined for heat transfer service, eddy-current examination to ASTM E243 may be requested. Cleanliness of the bore is important for conductor and vacuum applications, so pipe is supplied with capped ends and, where specified, purged and sealed. Mill certificates state the grade, temper, dimensions, chemical results and test values, and reference the applicable standard.
FAQ
Q: What does C10100 mean?
C10100 is the UNS designation for oxygen-free electronic copper, OFE or OFC, with a minimum copper content of 99.99% and oxygen limited to 0.0005% max.
Q: How does C10100 differ from C11000 tough pitch copper?
C10100 is produced without residual oxygen, so it has no copper oxide inclusions, higher conductivity and no risk of hydrogen embrittlement, which is why it costs more.
Q: What conductivity does the grade achieve?
Up to 101% IACS, equivalent to roughly 58.6 MS/m, and thermal conductivity of about 391 W/(m·K).
Q: Why is C10100 used in vacuum equipment?
It brazes and welds into vacuum-tight joints, is stable at high temperature in reducing atmospheres and does not outgas through oxide decomposition.
Q: What tempers are available for round pipe?
Annealed soft temper for bending and forming, and hard-drawn tempers where higher strength is needed, using the temper designations of ASTM B601.
Q: What standards apply to C10100?
ASTM B170 and ASTM F68 for the material, ASTM B111, ASTM B75 and ASTM B280 for tube and pipe, and ASTM B152 or ASTM B187 for flat and bar products.
Q: Is there a Chinese equivalent grade?
Yes. GB/T 5231 covers oxygen-free copper as TU0, TU1 and TU2, with TU0 corresponding to 99.99% copper at the lowest oxygen level.
