What's the Difference Between Copper T2 vs TU1 vs TU2?

T2, TU1, and TU2 are all typical grades of copper defined under the Chinese national standard (GB/T 5231). They belong to the category of purple copper (i.e., pure copper or industrial pure copper) and are primarily used to specify composition and performance levels of high-purity copper materials. These materials are widely applied in industry due to their excellent electrical conductivity, thermal conductivity, and workability. However, fundamentally, they do not belong to copper alloy systems formed by adding other metallic elements. In other words, they are base materials composed almost entirely of copper, playing a foundational role in electrical, electronic, and high-end manufacturing industries.

• T2: Oxygen-containing copper (No. 2 copper)

• TU1, TU2: Oxygen-free copper (No. 1 and No. 2 oxygen-free copper)

• Not copper alloys: Copper alloys typically refer to materials formed by adding elements such as Zn, Sn, Al, or Ni to copper (e.g., brass, bronze, cupronickel). These three grades, however, are high-purity copper (Cu ≥ 99.90%) with little to no alloying elements, and are therefore strictly classified as pure copper rather than copper alloys.

Equivalent International Grades (Industry Common)

• T2

• ASTM: C11000 (ETP copper)

• JIS: C1100

• DIN: SE-Cu / CW004A

• TU1

• ASTM: C10200 (Oxygen-free electronic)

• JIS: C1020

• DIN: OF-Cu / CW008A

• TU2

• ASTM: C10200 (often grouped with TU1)

• JIS: C1020

• DIN: OF-Cu

Composition and Physical Properties (Professional Comparison)

1. Composition (GB/T 5231)

• T2

• Cu+Ag ≥ 99.90%

• O ≤ 0.06% (typically 0.02%–0.05%)

• Total impurities ≤ 0.1%

• TU1

• Cu+Ag ≥ 99.97%

• O ≤ 0.001%

• Total impurities ≤ 0.03%

• TU2

• Cu+Ag ≥ 99.95%

• O ≤ 0.002%

• Total impurities ≤ 0.05%

2. Key Physical Properties

• Electrical conductivity (IACS)

• T2: 97%–98%

• TU1: ≥101% (highest)

• TU2: ≥100%

• Tensile strength (MPa)

• T2: 190–220

• TU1: 210–250

• TU2: 200–230

• Elongation

• T2: ≥25%

• TU1: ≥35%

• TU2: ≥30%

• Key differences

• T2 has “hydrogen embrittlement”: prone to cracking in high-temperature reducing atmospheres

• TU1/TU2: no hydrogen embrittlement; safe for vacuum/reducing environments

• TU1: highest purity; suitable for ultra-high vacuum, semiconductors, high-frequency applications

• TU2: cost-effective oxygen-free copper; slightly lower purity than TU1 but more economical

Processing Technology (Basically the Same for All Three)

1. Melting and Casting

• Induction furnace / reverberatory furnace

• T2: mildly oxidizing atmosphere, charcoal cover

• TU1/TU2: vacuum or protective gas (N₂, Ar), low-oxygen process

• Casting temperature: 1150–1230°C

2. Hot Working

• Hot rolling: 800–950°C, billet breakdown and scale removal

• Hot extrusion and forging: excellent plasticity

3. Cold Working

• Cold rolling, drawing, deep drawing, bending, spinning

• High workability, prone to work hardening

4. Heat Treatment

• Annealing (recrystallization): 300–600°C, stress relief and ductility recovery

• TU1/TU2: more stable during annealing, no hydrogen embrittlement risk

5. Welding

• Brazing, TIG welding, electron beam welding

• T2 should be used cautiously in high-temperature hydrogen environments

Main Application Fields and Products (Expanded)

In practical industrial applications, T2, TU1, and TU2 Copper sheets and bars, each serve different tiers of the manufacturing spectrum, collectively covering needs from general-purpose electrical materials to high-end electronics and advanced technologies. T2, due to its low cost, good workability, and wide availability, is the most commonly used material for general conductive and thermal applications. TU1, with its ultra-high purity and superior performance, is mainly used in cutting-edge fields requiring extreme cleanliness, electrical performance, and reliability. TU2 strikes a balance between performance and cost, making it a widely adopted oxygen-free copper solution in modern electronics, electrical engineering, and new energy industries. Together, these three grades form a complete application hierarchy of pure copper materials in modern industry.

T2 (General-purpose copper, largest usage)

• Wires and cables, busbars, copper strips, transformer/motor windings

• Radiators, heat exchangers, refrigeration tubes

• Hardware, rivets, gaskets, architectural decoration

• General conductive, thermal, and corrosion-resistant components

TU1 (High-purity oxygen-free copper, high-end)

Vacuum electronic devices (magnetrons, klystrons, microwave tubes)

• Semiconductor bonding wires, IC lead frames

• 5G/millimeter-wave RF cables and waveguides

• Aerospace, satellites, superconducting stabilizers

• Ultra-high vacuum equipment, laser components

TU2 (Cost-effective oxygen-free copper, mainstream)

• Vacuum electronic components, vacuum tubes, X-ray tube parts

• High-voltage wiring harnesses for new energy vehicles, battery connectors

• Charging connectors, high-frequency cables, waveguides

• High-reliability electronics, instrumentation, relays

• Welded/high-temperature components sensitive to hydrogen embrittlement

FAQ

Is TU1 better than T2 copper?

Yes, TU1 has higher purity and better conductivity, but it is more expensive.

Can TU2 replace TU1?

In many industrial applications, yes. TU2 offers a good balance between cost and performance.