Copper Alloy C18400-TH04
Precip hard
UNS C18400
TH04 = tD04 and precipitation hardened
Highest-strength commercial condition for small rod, wire and strip where maximum yield strength with high conductivity is needed.
Values for the TH04 condition
Other C18400 tempers and conditions
C18400 is listed in 7 conditions; see the grade overview at C18400.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Standard soft mill-annealed condition for bending, riveting and staking where high conductivity but only modest strength is needed. | 85 | 230 | 42 | 55 HB | 80 % IACS |
Solution heat treated | Choose for maximum formability/deep forming before the customer performs the ageing (precipitation) treatment; conductivity is low until aged. | 95 | 240 | 40 | 60 HB | 42 % IACS |
Solution heat treated and cold worked, half hard | Cold-drawn half-hard rod/wire for straightness and moderate strength where a customer ageing step is not planned. | 330 | 380 | 14 | 110 HB | 75 % IACS |
TF00Default Solution heat treated and precipitation hardened | The standard stocked electrode/contact condition: ~80% IACS with roughly 470 MPa tensile — pick it for spot-welding electrodes and current-carrying structural parts. | 380 | 470 | 18 | 140 HB | 82 % IACS |
Solution heat treated and cold worked, full hard | Hard-drawn unaged wire/rod where springiness and dimensional straightness matter more than peak strength. | 390 | 430 | 10 | 125 HB | 74 % IACS |
TD01 and precipitation hardened | Cold work before ageing raises yield strength above TF00 while keeping ~80% IACS — used for contact arms, commutator segments and high-load electrode holders. | 450 | 515 | 15 | 150 HB | 80 % IACS |
TH04This page TD04 and precipitation hardened | Highest-strength commercial condition for small rod, wire and strip where maximum yield strength with high conductivity is needed. | 485 | 550 | 12 | 160 HB | 80 % IACS |
What is C18400-TH04?
C18400-TH04 is C18400 in the TH04 condition — highest-strength commercial condition for small rod, wire and strip where maximum yield strength with high conductivity is needed. C18400-TH04 has a yield strength of 485 MPa (70.3 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 88% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 115 GPa (16.7 Msi). C18400-TH04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,070°C (1,958 °F). TF00 is the default condition FabDigit quotes; TH04 is available on request or by drawing note.
Advantages
- High service temperature — 380°C (716 °F), better than 97% of copper alloy grades
- High strength — 485 MPa (70.3 ksi), better than 88% of copper alloy grades
- High electrical conductivity — 80 % IACS, better than 84% of copper alloy grades
- Conducts heat well — 315 W/m·K (182 BTU/hr·ft·°F), better than 83% of copper alloy grades
C18400-TH04 properties
Typical room-temperature values for C18400-TH04; 11 are specific to this condition. Other listed values are C18400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C18400-TH04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,070°C (1,958 °F).
Mechanical12
C18400-TH04 has a yield strength of 485 MPa (70.3 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 88% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal6
C18400-TH04 is rated for continuous service to 380°C (716 °F). It conducts heat at 315 W/m·K (182 BTU/hr·ft·°F), better than 83% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
C18400-TH04 conducts electricity at 80 % IACS, better than 84% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C18400-TH04 takes about 57 MJ of energy and emits 3.8 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
C18400-TH04's machinability is fair (50/100, better than 69% of copper alloy grades); weldability fair (45/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C18400-TH04
Is C18400 easy to machine?
Machines like tough copper — gummy chips; use sharp positive-rake carbide, high speed, generous coolant; machine in the aged (TF00/TH01) temper for best finish.
Can C18400 be welded?
Excellent for resistance welding as an electrode material; GTAW/EBW possible with He shielding and low heat input but the HAZ over-ages and loses ~30–40% strength, so re-age after welding where possible.
Can C18400 be formed, bent or molded?
Form, deep-draw or head in the TB00/O61 soft tempers then solution treat (~980–1000 °C, water quench) and age (~450–500 °C, 2–4 h) for final properties.
What surface finishes work on C18400?
No anodizing; use bright dip/pickle to remove Cr-rich oxide, then nickel or silver plating for contacts, or leave bare — natural patina forms in service.
C18400 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 |
|---|---|---|
| Crprecipitation-hardening element | 0.4 – 1.2 | 0.8 |
| Fe | ≤ 0.15 | — |
| Si | ≤ 0.1 | — |
| Al | ≤ 0.1 | — |
| Zn | ≤ 0.1 | — |
| Pb | ≤ 0.05 | — |
| CuCu + named elements 99.5 % min (Ag counted as Cu) | balance | — |
C18400-TH04 — frequently asked
What is C18400-TH04 used for?
C18400-TH04 is typically used for resistance welding electrodes, electrical contacts, electrode tips and caps, switchgear current-carrying parts, connector bodies and conductive fixture components. In short: 82 % IACS chromium copper; 400 °C electrode service; age-hardenable, 18 % elongation.
What is the yield strength of C18400-TH04?
C18400-TH04 has a typical yield strength of 485 MPa (70.3 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 88% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C18400-TH04 easy to machine?
Reasonably — machinability is rated fair (50/100, better than 69% of copper alloy grades). Machines like tough copper — gummy chips; use sharp positive-rake carbide, high speed, generous coolant; machine in the aged (TF00/TH01) temper for best finish.
Can C18400-TH04 be welded?
With care — weldability is rated fair (45/100). Excellent for resistance welding as an electrode material; GTAW/EBW possible with He shielding and low heat input but the HAZ over-ages and loses ~30–40% strength, so re-age after welding where possible.
What surface finishes work on C18400-TH04?
No anodizing; use bright dip/pickle to remove Cr-rich oxide, then nickel or silver plating for contacts, or leave bare — natural patina forms in service.
Can C18400-TH04 be formed, bent or molded?
Form, deep-draw or head in the TB00/O61 soft tempers then solution treat (~980–1000 °C, water quench) and age (~450–500 °C, 2–4 h) for final properties.
What is the maximum service temperature of C18400-TH04?
C18400-TH04 is rated for continuous use to about 380°C (716 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C18400-TF00 and C18400-O61?
TF00 is the default condition — the standard stocked electrode/contact condition: ~80% IACS with roughly 470 MPa tensile — pick it for spot-welding electrodes and current-carrying structural parts. O61: standard soft mill-annealed condition for bending, riveting and staking where high conductivity but only modest strength is needed. Yield strength is 380 MPa in TF00 versus 85 MPa in O61.
Sources
- ASTM B224 — Classification of Coppers — ASTM International (2021)
- ASTM B133 / B187 — Copper rod, bar and shapes — ASTM International (2020)
- CDA Alloy Datasheet — Chromium Copper (C182xx/C184xx) — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties of Nonferrous Alloys — ASM International (1990)
- RWMA Class 2 electrode material bulletin — Resistance Welder Manufacturers' Association (2015)
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.