Introduction
This article explains C10100 oxygen-free copper tubes for HVAC and electronics service. Oxygen-free copper covers the C10100, C10200 and C10300 families, which are refined to very low oxygen and impurity levels so that the material stays ductile, weldable and stable in hydrogen-bearing atmospheres. These grades are used wherever ordinary tough-pitch copper is rejected because of oxide inclusions, hydrogen embrittlement risk or inconsistent conductivity.
What Oxygen-Free Copper Means
Oxygen-free copper is melted and cast under a protective atmosphere and deoxidized so that the oxygen content stays far below the level found in electrolytic tough pitch copper. The result is a metal free of cuprous oxide particles at the grain boundaries. When the tube or strip is heated for brazing, welding or bright annealing, there is no oxide for hydrogen to reduce, so the internal steam voids that cause cracking in ETP copper simply do not form.
Grade Families and Composition
The C10100 grade is the highest-purity oxygen-free electronic grade, C10200 is the general oxygen-free grade, and C10300 is an oxygen-free grade with a small phosphorus addition that raises the softening temperature while keeping excellent conductivity. All three are covered by ASTM B170 for rod and bar and by the corresponding tube and strip standards such as ASTM B75, B68 and B152.
| Grade | Cu % Min | O % Max | Typical Use |
|---|---|---|---|
| C10100 | 99.99 | 0.0005 | Electronics, vacuum, lead frames |
| C10200 | 99.95 | 0.001 | General oxygen-free parts |
| C10300 | 99.95 | 0.001 | High-softening-temperature service |
Properties and Processing Behavior
Oxygen-free copper combines electrical conductivity in the range of 100 to 101 percent IACS with good formability, excellent ductility and stable properties after annealing. It bends, flares, expands and cold-forms reliably, and it can be torch-brazed and welded without the hydrogen embrittlement risk of tough-pitch grades. The absence of oxide also gives a cleaner surface for plating, sputtering and vacuum applications.
Typical Applications
The main uses are electrical and electronic components, coaxial cable and waveguide, vacuum and electron tubes, transformer windings, bus bars, lead frames and heat dissipation tubes for electronics cooling. In HVAC work the oxygen-free grades are specified where brazed joints must be leak-tight over long service lives, and in instrumentation where stable electrical properties are required.
Specification and Verification
Order against a recognized standard such as ASTM B170, B75 or B152 with the temper, dimensions and surface condition stated. Verify the oxygen content, conductivity and impurity analysis on the mill certificate, and confirm that the delivered lot matches the agreed grade designation and test results.
