Copper Alloy C18000 · precip hard
Copper Alloy C18000-TH04
Properties of the TH04 condition, compared with the other C18000 tempers.
Choose for maximum strength/hardness in drawn rod, wire or small-section electrodes where ductility is less critical.
What is C18000-TH04?
C18000-TH04 is C18000 in the TH04 condition — choose for maximum strength/hardness in drawn rod, wire or small-section electrodes where ductility is less critical. C18000-TH04 has a yield strength of 690 MPa (100 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 131 GPa (19 Msi). C18000-TH04 has a density of 8.78 g/cm³ (0.317 lb/in³), heavier than 52% of copper alloy grades. It melts at 1,030°C (1,886 °F). H is the default condition FabDigit quotes; TH04 is available on request or by drawing note.
Advantages
- High strength — 690 MPa (100 ksi), better than 96% of copper alloy grades
- High service temperature — 380°C (716 °F), better than 96% of copper alloy grades
- Stiff — 131 GPa (19 Msi), better than 91% of copper alloy grades
- High electrical conductivity — 46 % IACS, better than 77% of copper alloy grades
- Conducts heat well — 195 W/m·K (112.7 BTU/hr·ft·°F), better than 76% of copper alloy grades
Limitations
- Limited ductility — 8%, worse than 83% of copper alloy grades
- Limited formability — 15/100, worse than 82% of copper alloy grades
C18000-TH04 properties
Typical room-temperature values for C18000-TH04 — 12 properties are specific to this condition; the rest are grade-level values shared by every C18000 temper. Each bar shows where the value sits among the copper alloy grades in FabDigit's library — further right is higher.
Physical3
C18000-TH04 has a density of 8.78 g/cm³ (0.317 lb/in³), heavier than 52% of copper alloy grades. It melts at 1,030°C (1,886 °F).
Mechanical12
C18000-TH04 has a yield strength of 690 MPa (100 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 131 GPa (19 Msi).
Thermal6
C18000-TH04 is rated for continuous service to 380°C (716 °F). It conducts heat at 195 W/m·K (112.7 BTU/hr·ft·°F), better than 76% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C18000-TH04 conducts electricity at 46 % IACS, better than 77% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C18000-TH04 takes about 56 MJ of energy and emits 4 kg of CO₂ — less than 61% of copper alloy grades. Typical recycled content is 30%.
Manufacturability6
C18000-TH04's machinability is good (55/100, better than 72% of copper alloy grades); weldability fair (35/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other C18000 tempers and conditions
C18000 is also supplied in 2 other conditions. The full side-by-side table is on the C18000 overview.
- HDefaultStandard stocked condition: best balance of ~690 MPa strength with ~48 % IACS conductivity for welding electrodes, electrode holders and mould components.585 MPa yield · 200 HB
- TH04Choose for maximum strength/hardness in drawn rod, wire or small-section electrodes where ductility is less critical.690 MPa yield · 225 HB
- TB00Soft solution-treated stock for forming, deep machining or heavy cold work before the ageing treatment.140 MPa yield · 90 HB
Working with C18000-TH04
Is C18000 easy to machine?
Machines better than pure copper — use sharp carbide tools, positive rake, high speed and generous coolant; machine in the aged condition for good finish and to avoid post-age distortion.
Can C18000 be welded?
Fusion welding is generally not recommended (over-ageing and porosity); join by brazing, silver soldering or mechanical/press fits, and re-age locally if heat-affected.
Can C18000 be formed, bent or molded?
Form, bend or cold-draw in the TB00 solution-treated state, then age ~450–500 °C for 2–3 h; hardened material has limited cold ductility.
What surface finishes work on C18000?
Not anodisable; takes bright polish, electroless/electrolytic Ni or Cr plating, or chemical blackening — degrease well because Cr/Si surface oxides hinder plating adhesion.
C18000 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 |
|---|---|---|
| Ni | 1.8 – 3 | 2.4 |
| Si | 0.4 – 0.8 | 0.6 |
| Cr | 0.1 – 0.8 | 0.4 |
| CuCu + named elements 99.5 % min (Ag counted as Cu) | balance | — |
C18000-TH04 — frequently asked
What is C18000-TH04 used for?
C18000-TH04 is typically used for resistance welding electrodes and holders (RWMA Class 3), continuous-casting mould components, mould and die inserts, switchgear components, resistance welding tips and high-current conductive structural parts. In short: oxidation resistant copper.
What is the yield strength of C18000-TH04?
C18000-TH04 has a typical yield strength of 690 MPa (100 ksi) and a tensile strength of 760 MPa (110 ksi) — stronger than 96% of copper alloy grades. Strength varies by condition: see the 3 listed tempers.
Is C18000-TH04 easy to machine?
Reasonably — machinability is rated good (55/100, better than 72% of copper alloy grades). Machines better than pure copper — use sharp carbide tools, positive rake, high speed and generous coolant; machine in the aged condition for good finish and to avoid post-age distortion.
Can C18000-TH04 be welded?
With care — weldability is rated fair (35/100). Fusion welding is generally not recommended (over-ageing and porosity); join by brazing, silver soldering or mechanical/press fits, and re-age locally if heat-affected.
What surface finishes work on C18000-TH04?
Not anodisable; takes bright polish, electroless/electrolytic Ni or Cr plating, or chemical blackening — degrease well because Cr/Si surface oxides hinder plating adhesion.
Can C18000-TH04 be formed, bent or molded?
Form, bend or cold-draw in the TB00 solution-treated state, then age ~450–500 °C for 2–3 h; hardened material has limited cold ductility.
What is the maximum service temperature of C18000-TH04?
C18000-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 C18000-H and C18000-TB00?
H is the default condition — standard stocked condition: best balance of ~690 MPa strength with ~48 % IACS conductivity for welding electrodes, electrode holders and mould components. TB00: soft solution-treated stock for forming, deep machining or heavy cold work before the ageing treatment. Yield strength is 585 MPa in H versus 140 MPa in TB00.
Can FabDigit make parts in C18000-TH04?
Yes — C18000-TH04 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Copper Alloy C18000 datasheet (UNS C18000) — Copper Development Association (copper.org) (2023)
- ASTM B441 / B422 – copper-nickel-silicon-chromium rod, bar and plate — ASTM International (2019)
- RWMA Bulletin 16 – Resistance Welding Electrode Materials, Class 3 — AWS / RWMA (2017)
- ASM Handbook Vol.2 — Properties of Nonferrous Alloys — ASM International (1990)
- CuNi2SiCr / C18000 electrode and mould alloy datasheet — Copper alloy producers (typical values) (2022)
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.