In C10100 fabrication, the "temper" defines the physical limit of your design. Because 99.99% pure copper contains no alloying elements like zinc or tin, its mechanical strength relies entirely on cold-working (strain hardening). Selecting the wrong state-such as using Soft (Annealed) copper for a structural busbar-will result in the material "smushing" under bolt torque. Conversely, using Full Hard copper for a tight-radius bend will cause immediate fracturing. To achieve the 101% IACS conductivity and vacuum integrity required for your project, you must match the temper to your specific fabrication method.
Why does C10100 require cold-working for mechanical strength?
Annealed C10100 Oxygen-Free Electronic copper has a yield strength of only 10 ksi. This state is ideal for deep drawing but offers zero structural rigidity. As the material is cold-rolled or drawn, its grain structure is compressed, increasing its hardness and tensile strength.
When sourcing C10100 Round, Square & Flat Bar, the Half-Hard (H02) temper is the industry standard. It provides the stiffness needed to resist electromagnetic forces in transformers while maintaining enough ductility for secondary machining.
C10100 Hardness and Strength Reference
| Temper Designation | ASTM Code | Rockwell F (HRF) | Vickers (HV) | Tensile Strength (ksi) |
| Soft (Annealed) | OS025 | 40 - 45 | 45 - 55 | 30 - 34 |
| 1/4 Hard | H01 | 54 - 64 | 65 - 80 | 32 - 40 |
| Half Hard | H02 | 77 - 89 | 90 - 110 | 37 - 46 |
| Full Hard | H04 | 90 - 98 | 110 - 130 | 43 - 52 |
How to prevent cracking in bent C10100 plates?
Fractures during bending are usually caused by choosing a temper that is too hard for the required radius. For C10100 Plate and Sheet, the "Bend Radius-to-Thickness" (R/t) ratio is the decisive metric.
A Full-Hard (H04) plate requires a bend radius at least 3x its thickness. If your assembly requires a tight 90-degree fold in a compact housing, you must specify Soft (OS025) or 1/4 Hard (H01) material. Attempting to force a hard grain structure into a sharp bend will snap the 99.99% copper fibers on the outer radius.
Does hardness affect C10100 CNC machinability?
Yes. The C10100 machinability rating is significantly improved by using harder tempers. Annealed copper is "gummy"; it sticks to the tool and creates a Built-Up Edge (BUE), which ruins the C10100 surface finish Ra.
For precision parts like UHV flanges or liquid-cooled electrodes, using Half-Hard (H02) material allows the cutting tool to shear the copper grain cleanly. This reduces "smearing" and ensures that the 101% IACS surface remains free of the microscopic tears that cause virtual leaks in vacuum systems.
Temper Selection by Process
| Fabrication Process | Recommended Temper | Reason |
| Deep Drawing / Shells | Soft (OS025) | Maximum elongation without tearing |
| Busbar Bending | Half-Hard (H02) | Balance of stiffness and formability |
| Precision Milling | Half-Hard (H02) | Prevents gummy smearing and burrs |
| Structural Spacers | Full-Hard (H04) | Highest resistance to deformation |
FAQ
1. Does 101% IACS conductivity drop as the copper gets harder?
Yes, but the drop is marginal. Severe cold-working (Full Hard) increases the density of lattice dislocations, which can lower conductivity by approximately 0.2% to 0.5%. For most power applications, the gain in mechanical strength outweighs this minor electrical loss.
2. Will welding or brazing change the temper of my C10100 part?
Yes. High temperatures (above 250°C) will cause the material to recrystallize. As detailed in our guide on how to weld C10100, the heat-affected zone (HAZ) will return to a Soft state. You must account for this loss of yield strength in your structural design.
3. How do I choose between Rockwell F and Vickers hardness?
Rockwell F is common for bulk material like thick bars and plates. Vickers (HV) is used for thin foils or precision CNC parts because its diamond indenter provides a more localized reading without damaging the 99.99% pure surface.
4. Why did my C10100 part develop "Orange Peel" after bending?
This is a sign of large grain size, often found in over-annealed Soft copper. We control grain size per ASTM F68 to ensure a smooth surface after forming, maintaining the integrity of the 101% IACS path.
5. Can I "stress-relief" a hard C10100 part without softening it?
Yes, through a low-temperature bake (approx. 150°C-180°C). This removes internal stresses from the rolling process to prevent warping during machining, without significantly dropping the Rockwell hardness.
6. Is there a "Special Temper" for cryogenic RRR applications?
For cryogenic magnets, we often provide a specific "RRR Grade" with controlled annealing. This ensures a RRR value of 100-450, providing the absolute lowest resistivity at liquid helium temperatures.
GNEE METAL Product Range
| Product Type | Shapes Available | Common Grades | Diameter/Thickness Range | Length/Width Range | Applications |
|---|---|---|---|---|---|
| Copper Tubes | Round, Square, Rectangular, Coiled | C10100, C10200, C11000, C12200, C12000 | OD: 0.5mm - 300mm Wall: 0.1mm - 20mm | Up to 6000mm or custom | HVAC, Plumbing, Heat Exchangers, Refrigeration, Hydraulic Lines |
| Copper Plates & Sheets | Flat Sheets, Perforated, Embossed, Tread Plate | C10100, C11000, C12200, C23000, C26000 | Thickness: 0.1mm - 200mm | Width: Up to 2500mm Length: Up to 6000mm | Electrical Busbars, Roofing, Cladding, Gaskets, Transformers |
| Copper Bars & Rods | Round Bar, Square Bar, Hexagonal Bar, Flat Bar | C10100, C11000, C14500, C17200, C18200 | Diameter: 1mm - 300mm | Length: 1000mm - 4000mm | Machined Components, Electrical Contacts, Busbars, Fasteners |
| Copper Wires | Round Wire, Flat Wire, Square Wire, Stranded, Braided | C11000, C11600, C17200, C17510 | Diameter: 0.05mm - 12mm | Coil weights: 1kg - 500kg | Electrical Wiring, Cables, Springs, Mesh, Welding Wire |
| Copper Strips & Coils | Thin Strip, Foil, Slit Coil, Profile Strip | C11000, C12200, C19400, C26000, C26800 | Thickness: 0.03mm - 5mm | Width: 2mm - 1000mm Coil ID: 300mm - 600mm | Transformers, Radiators, Shielding, Terminals, Connectors |
About Our Factory
We operate a full range of production lines including extrusion presses, cold drawing benches, high-speed rolling mills, slitting lines, and precision CNC machining centers, enabling us to produce copper tubes, plates, bars, wires, and strips entirely in-house. For quality assurance, we maintain a dedicated inspection laboratory equipped with spectral analyzers, universal testing machines, hardness testers, surface roughness testers, and optical measuring instruments. Every batch is tested for chemical composition, mechanical properties, and dimensional accuracy before shipment. Our production capacity reaches 500+ tons per month, and we hold ISO 9001:2015 certification with full traceability from raw material to finished product. Whether you need standard mill stock or custom-processed components, we deliver precision copper products with short lead times and complete material certification.
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