What C10300 Oxygen Free Extra Low Phosphorus Copper Is
C10300 is an oxygen free copper with a deliberate extra low phosphorus addition of 0.001 - 0.005 %. Copper plus silver is 99.95 % minimum. The phosphorus removes the last traces of oxygen from the melt, so the finished tube contains no cuprous oxide and cannot suffer hydrogen embrittlement during annealing, brazing or welding in a reducing atmosphere. At the same time the addition is small enough that electrical and thermal conductivity remain high, which is the balance that distinguishes the grade from both tough pitch copper and the higher phosphorus C12200.
In the designation systems the alloy corresponds to Cu-HCP and CW021A in CEN/TS 13388 and EN 1652, to the GB/T 5231 TUP series of deoxidized oxygen free copper, and to the high conductivity oxygen free tube grades supplied for electrical work. It is stocked and produced as seamless and welded and drawn tube, pipe, bus bar and special sections.
Chemical and Conductivity Data
| Element | Copper plus silver | Phosphorus | Oxygen |
|---|---|---|---|
| Content, % | 99.95 min | 0.001 - 0.005 | 0.001 max |
ASTM B152 sets a minimum electrical conductivity of 85 % IACS for this grade, which is about 49 MS/m by volume and a resistivity of roughly 2.0 µΩ·cm. Because thermal and electrical conductivity track each other in copper, the corresponding thermal conductivity is about 340 W/(m·K). Density is 8.94 g/cm³ and the melting point is 1083 °C. Values of this order are what allow the tube to carry current as a conductor and to act as a heat transfer surface in the same component, as happens in bus bars, waveguides and condenser tube.
Type K, L and M Walls and EN 1652 Tempers
When conductor tube is ordered to ASTM B88 the wall is specified by class: type K is the heavy wall used for burial and the highest pressures, type L is the medium wall used for general service, and type M is the light wall used for low pressure work where weight saving matters. The class is a wall thickness definition, so it must be quoted together with the outside diameter.
Where the order follows EN 1652, the tube is specified by temper designation and minimum tensile strength:
| Temper | Tensile strength Rm, MPa | Typical application |
|---|---|---|
| R220 | 220 - 260 | Annealed tube for bending and forming |
| R240 | 240 - 300 | Lightly worked tube and sheet |
| R290 | 290 - 360 | Half hard conductor and structural parts |
| R360 | 360 min | Hard temper for stiffness and support spacing |
Applications and Applied Specifications
C10300 tube and pipe are used where conductivity, freedom from embrittlement and good forming behaviour are all required. Seamless condenser and heat exchanger tube, including U-bend forms, follows the ASME SB395 and ASTM B359/B359M family. Seamless pipe and tube are ordered to ASME SB42 and ASME SB75 or ASTM B42 and ASTM B75/B75M. Ferrule and condenser tube stock follows ASME SB111 and ASTM B111/B111M. Bus bar stock follows ASTM B188, in which the same oxygen free copper is produced as flat, square and rectangular bar. Rectangular waveguide follows ASTM B372, and bright annealed tube for electrical and instrument work follows ASTM B68/B68M, ASTM B641, ASTM B698, ASTM B447, ASTM B743 and ASTM B716 as applicable to the particular form.
Typical duties include electrical conductor tube and connectors, bus bar and switchgear components, rectangular waveguide, condenser and heat exchanger tube, billet mould and continuous casting mould tube, commutators, pressure vessel internals, and general corrosion resistant process piping.
Supply Range, Inspection and Delivery
Tube is produced with outside diameters from 12 mm to 108 mm and wall thickness from 0.7 mm to 2.5 mm in the standard size chart, supplied in 3 m straight lengths in strapped bundles; other diameters, walls and lengths are produced to drawing. The full mill range extends from smaller instrument tube to large diameter pipe.
Inspection on each lot covers chemical composition by spectrometer with particular attention to the phosphorus and oxygen limits, electrical conductivity testing, tensile and hardness testing to confirm the ordered temper, dimensional checks on outside diameter, wall and length, grain size on annealed tube, eddy current testing, and hydrostatic pressure testing when a pressure class is quoted. Bundle weights and piece counts are recorded for each size. Export packing uses plastic film with wooden cases or steel strapped bundles, and a mill test certificate is issued for every heat showing composition, conductivity and mechanical results.
Frequently Asked Questions
Q: What does the extra low phosphorus in C10300 do?
A: It deoxidizes the melt completely, so the tube is immune to hydrogen embrittlement, while the low level of 0.001 - 0.005 % keeps electrical conductivity at a minimum of 85 % IACS.
Q: Which standard defines the type K, L and M classes?
A: ASTM B88 defines the three wall thickness classes of copper water tube. Type K is the heaviest wall, type L the medium wall and type M the lightest wall, and the class must be quoted together with the diameter.
Q: What do the EN 1652 tempers mean?
A: They are strength designations: R220 covers annealed tube at 220 - 260 MPa, R240 lightly worked tube at 240 - 300 MPa, R290 half hard material at 290 - 360 MPa and R360 hard temper at a minimum of 360 MPa.
Q: Where is C10300 tube used in electrical work?
A: In bus bar, switchgear and conductor assemblies, rectangular waveguide to ASTM B372, commutators, and condenser or heat exchanger tube where the component both carries current and transfers heat.
Q: What sizes are normally available?
A: The standard size chart runs from 12 mm to 108 mm outside diameter with wall thickness from 0.7 mm to 2.5 mm in 3 m lengths, and other sizes are produced to drawing.
Q: How is conductivity verified before shipment?
A: Each heat is tested for electrical conductivity in addition to spectrometer analysis, tensile testing and dimensional checks, and the measured values are stated on the mill test certificate.
