What is the alternative name of pure copper - Knowledge

1. What is the alternative name of pure copper?

Pure copper is commonly known by the alternative name "copper" (the base name) and the widely recognized historical/industrial alias "red copper" (due to its characteristic reddish-orange hue when unoxidized). In metallurgical and commercial contexts, it is also frequently referred to as "oxygen-free copper" (OFC) or "electrolytic tough pitch copper" (ETP) - though these are technically subcategories of pure copper with specific impurity controls (e.g., low oxygen content for OFC). Another less common but traditional term is "native copper", which refers to naturally occurring pure copper deposits.

2. What is the copper content of pure copper?

The copper (Cu) content of pure copper is defined by strict metallurgical standards, typically ≥ 99.3% to 99.99% (by mass), depending on the specific grade and application requirements:

Commercial pure copper (e.g., C11000 in ASTM standard, Cu-ETP): Copper content ≥ 99.90%, with trace impurities (e.g., oxygen ≤ 0.04%, iron ≤ 0.005%, sulfur ≤ 0.004%) to balance processability and cost.

Oxygen-free pure copper (e.g., C10200, Cu-OF; C10100, Cu-OFHC): Copper content ≥ 99.95% (C10200) or ≥ 99.99% (C10100, "oxygen-free high conductivity" copper). These grades have extremely low oxygen (≤ 0.001%) and impurity levels, optimized for high electrical conductivity and corrosion resistance.

International standards (e.g., EN 1976:2016, GB/T 5231-2022): Pure copper grades (e.g., Cu-ETP, Cu-OF) consistently require copper content ≥ 99.90% as the minimum threshold for classification.

info-441-447 info-443-441

info-443-441 info-446-450

3. What is the typical hardness of pure copper?

The hardness of pure copper is highly dependent on its heat treatment state (annealed vs. cold-worked) and measurement method. Below are the typical values for common conditions, using industry-standard testing methods:

Heat Treatment State	Brinell Hardness (HB)	Vickers Hardness (HV)	Rockwell Hardness (HRB)	Key Notes
Full Annealed (Soft)	35 – 45 HB	30 – 40 HV	20 – 30 HRB	Fully recrystallized (annealing temp: 600–700°C), maximum ductility, minimal internal stress. Used for deep drawing, bending, or applications requiring formability.
Cold-Worked (Half-Hard)	60 – 80 HB	65 – 85 HV	50 – 60 HRB	30–50% cold deformation (e.g., rolling, drawing), balanced strength and ductility. Suitable for fasteners, springs, or components needing moderate rigidity.
Cold-Worked (Full-Hard)	100 – 120 HB	105 – 125 HV	70 – 80 HRB	70–90% cold deformation, highest hardness but reduced ductility. Used for high-strength parts like electrical contacts or precision components.

Additional Technical Details:

Measurement standards: Hardness values are based on ASTM E10 (Brinell), ASTM E92 (Vickers), and ASTM E18 (Rockwell) test methods, using standard indentation parameters (e.g., 500 kg load for Brinell, 100 g load for Vickers).

Effect of impurities: Trace elements (e.g., iron, phosphorus) can slightly increase hardness but may reduce conductivity. High-purity OFHC copper (C10100) has marginally lower hardness in the annealed state (30–35 HB) compared to commercial ETP copper (35–45 HB) due to fewer impurities.

Post-processing impact: Annealing after cold working restores softness, while further cold deformation increases hardness proportionally (up to ~130 HB for extreme cold work, though ductility becomes very low).