Copper Alloy T3-T (Extra hard)
Heat-treated state
GB T3 · ASTM B152 · EN CW004A, Cu-ETP · JIS C1100
Heavily cold-rolled strip/sheet for springy contacts, shims and flat parts that must stay stiff; almost no bending capability.
Values for the T condition
Other T3 tempers and conditions
T3 is listed in 6 conditions; see the grade overview at T3.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Choose hot-rolled plate above 10 mm for the lowest cost per kg in soft, weldable heavy sections; the surface carries light scale and yield is only 65 MPa at 96% IACS. | 65 | 215 | 40 | 45 HB | 96 % IACS |
MDefault Thermomechanically controlled processed | Default stock condition for sheet, strip, tube and gaskets — maximum ductility for deep drawing, bending and forming. | 70 | 230 | 45 | 45 HB | 97 % IACS |
Quarter hard | Light cold reduction — better flatness and edge quality than M while still bendable to tight radii. | 195 | 265 | 25 | 65 HB | 96 % IACS |
Half hard | Best balance of strength and workability for machined parts, busbar-style brackets and moderate bending. | 245 | 300 | 14 | 80 HB | 96 % IACS |
Hard | Standard condition for drawn rod, bar and hard sheet where stiffness, straightness and machinability matter more than bending. | 305 | 350 | 8 | 100 HB | 95 % IACS |
TThis page Extra hard | Heavily cold-rolled strip/sheet for springy contacts, shims and flat parts that must stay stiff; almost no bending capability. | 350 | 385 | 3 | 110 HB | 94 % IACS |
What is T3-T?
T3-T is T3 heat treated to T — heavily cold-rolled strip/sheet for springy contacts, shims and flat parts that must stay stiff; almost no bending capability. T3-T has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 385 MPa (55.8 ksi) — stronger than 74% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 117 GPa (17 Msi). T3-T has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,065°C (1,949 °F). M is the default condition FabDigit quotes; T is available on request or by drawing note.
Advantages
- Conducts heat well — 378 W/m·K (218.4 BTU/hr·ft·°F), better than 91% of copper alloy grades
- High electrical conductivity — 94 % IACS, better than 90% of copper alloy grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 100% of copper alloy grades
- Limited ductility — 3%, worse than 97% of copper alloy grades
T3-T properties
Typical room-temperature values for T3-T; 13 are specific to this condition. Other listed values are T3 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
T3-T has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Mechanical12
T3-T has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 385 MPa (55.8 ksi) — stronger than 74% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
T3-T is rated for continuous service to 120°C (248 °F). It conducts heat at 378 W/m·K (218.4 BTU/hr·ft·°F), better than 91% of copper alloy grades. Thermal expansion is 17.7 µm/m·K (9.83 µin/in·°F).
Electrical3
T3-T conducts electricity at 94 % IACS, better than 90% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 86% of copper alloy grades.
Sustainability4
Producing a kilogram of T3-T takes about 57 MJ of energy and emits 3.5 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
T3-T's machinability is fair (40/100, better than 57% of copper alloy grades); weldability fair (45/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with T3-T
Is T3 easy to machine?
Gummy and long-chipping — use sharp positive-rake, polished-flute tools, high speed, low feed and generous emulsion; Y/Y2 tempers cut far better than M.
Can T3 be welded?
TIG/MIG with pure-Ar/He and high preheat works but oxygen content risks hydrogen embrittlement — avoid reducing atmospheres above ~400 °C; brazing/soldering is the preferred joining route.
Can T3 be formed, bent or molded?
M temper deep-draws, spins and bends superbly (bend radius ≈ 0 t); interstage anneal at 400–600 °C to restore ductility after ~50 % cold work.
What surface finishes work on T3?
Not anodizable — mechanically polish then lacquer, or electroplate Ni/Sn/Ag/Cr; chemical patination (black/green) is common for decorative parts.
T3 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Otypical for tough-pitch T3, not always specified | ≤ 0.1 | 0.05 |
| Bi | ≤ 0 | — |
| Pb | ≤ 0.01 | — |
| Sb | ≤ 0.01 | — |
| As | ≤ 0.01 | — |
| Fe | ≤ 0.05 | — |
| S | ≤ 0.01 | — |
| total impuritiessum of all impurities per GB/T 5231 | ≤ 0.3 | — |
| CuCu + Ag, balance; oxygen-bearing (tough pitch) | ≥ 99.7 (balance) | — |
T3-T — frequently asked
What is T3-T used for?
T3-T is typically used for rivets, washers, hardware fittings and general stamped parts. In short: economical general-purpose copper; excellent stamping formability; lower-purity tough-pitch grade.
What is the yield strength of T3-T?
T3-T has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 385 MPa (55.8 ksi) — stronger than 74% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is T3-T easy to machine?
Not especially — machinability is rated fair (40/100, better than 57% of copper alloy grades). Gummy and long-chipping — use sharp positive-rake, polished-flute tools, high speed, low feed and generous emulsion; Y/Y2 tempers cut far better than M.
Can T3-T be welded?
With care — weldability is rated fair (45/100). TIG/MIG with pure-Ar/He and high preheat works but oxygen content risks hydrogen embrittlement — avoid reducing atmospheres above ~400 °C; brazing/soldering is the preferred joining route.
What surface finishes work on T3-T?
Not anodizable — mechanically polish then lacquer, or electroplate Ni/Sn/Ag/Cr; chemical patination (black/green) is common for decorative parts.
Can T3-T be formed, bent or molded?
M temper deep-draws, spins and bends superbly (bend radius ≈ 0 t); interstage anneal at 400–600 °C to restore ductility after ~50 % cold work.
What is the maximum service temperature of T3-T?
T3-T is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between T3-M and T3-T?
M is the default condition — default stock condition for sheet, strip, tube and gaskets — maximum ductility for deep drawing, bending and forming. T: heavily cold-rolled strip/sheet for springy contacts, shims and flat parts that must stay stiff; almost no bending capability. Yield strength is 70 MPa in M versus 350 MPa in T.
Sources
- ASTM B152/B152M Copper Sheet, Strip, Plate and Rolled Bar — ASTM (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- CDA alloy datasheet C11000 (ETP copper) — Copper Development Association (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.