1. Chemical Composition (Purity)
The core distinction lies in the minimum copper (plus silver, Cu+Ag) content and the maximum allowable total impurities:
T1 Copper: The highest-purity grade. Cu+Ag ≥ 99.95%, total impurities ≤ 0.05%. It has extremely strict limits on harmful elements like bismuth (Bi ≤ 0.001%), antimony (Sb ≤ 0.002%), arsenic (As ≤ 0.002%), iron (Fe ≤ 0.005%), lead (Pb ≤ 0.003%), and oxygen (O). This grade approaches the purity of oxygen-free copper in many production scenarios.
T2 Copper: The most widely used general-purpose grade. Cu+Ag ≥ 99.90%, total impurities ≤ 0.10%. It allows slightly higher impurity levels than T1, but still maintains very high purity.
T3 Copper: The lowest-purity grade. Cu+Ag ≥ 99.70%, total impurities ≤ 0.30%. It contains more impurities that degrade conductivity and has a higher oxygen content compared to T1 and T2.
2. Physical & Functional Properties
Electrical & Thermal Conductivity
T1: Exhibits the highest electrical and thermal conductivity due to minimal impurities. It is ideal for applications requiring ultra-high performance.
T2: Offers excellent conductivity, slightly lower than T1 but sufficient for nearly all standard electrical and thermal applications.
T3: Has good but lower conductivity. Impurities act as scattering centers for electrons and phonons, reducing efficiency.
Machinability & Weldability
T1 & T2: Both possess excellent cold and hot workability, ductility, and formability. They can be easily drawn, bent, stamped, and deep-drawn. They are readily weldable and brazeable.
T3: Slightly harder and less ductile than T2 due to higher impurity content. While still workable, it is less suitable for very fine or complex forming operations. Its higher oxygen content increases the risk of "hydrogen embrittlement" in high-temperature reducing atmospheres, limiting certain welding and annealing processes.
3. Typical Applications
T1 Copper
Used in high-purity, high-performance applications where even minor impurities could cause failure:
High-frequency waveguides and coaxial cables
Precision electronic components and integrated circuit lead frames
Ultra-high-purity conductors for scientific instruments
Special aerospace and military components
T2 Copper
The workhorse of the copper industry, used for general-purpose electrical and thermal applications:
Power transmission wires and cables
Busbars, electrical contacts, and conductive screws
Heat exchangers, radiators, and plumbing tubes
Electrical motor and transformer windings
General industrial conductors and corrosion-resistant parts
T3 Copper
Used for structural and less critical components where cost is a priority and high conductivity is not essential:
Electrical switch parts, washers, rivets, and fasteners
General plumbing fittings and pipe nozzles
Less critical conductive elements and structural supports
Applications where formability and basic conductivity are sufficient, but premium performance is not required
Summary
In summary, T1, T2, and T3 represent a hierarchy of purity and performance. T1 is for premium, high-purity needs; T2 is the versatile, all-around choice for most industrial uses; and T3 is the economical option for less demanding structural and general applications.
