Copper Alloy C18000 · heat-treated state · default condition
Copper Alloy C18000-H
Properties of the H condition, compared with the other C18000 tempers.
Standard stocked condition: best balance of ~690 MPa strength with ~48 % IACS conductivity for welding electrodes, electrode holders and mould components.
What is C18000-H?
C18000-H is C18000 heat treated to H — standard stocked condition: best balance of ~690 MPa strength with ~48 % IACS conductivity for welding electrodes, electrode holders and mould components. C18000-H has a yield strength of 585 MPa (84.8 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 93% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 131 GPa (19 Msi). C18000-H 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).
Advantages
- High service temperature — 400°C (752 °F), better than 97% of copper alloy grades
- High strength — 585 MPa (84.8 ksi), better than 93% of copper alloy grades
- Stiff — 131 GPa (19 Msi), better than 91% of copper alloy grades
- High electrical conductivity — 48 % IACS, better than 77% of copper alloy grades
- Conducts heat well — 200 W/m·K (115.6 BTU/hr·ft·°F), better than 76% of copper alloy grades
C18000-H properties
Typical room-temperature values for C18000-H — 14 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-H 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-H has a yield strength of 585 MPa (84.8 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 93% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 131 GPa (19 Msi).
Thermal6
C18000-H is rated for continuous service to 400°C (752 °F). It conducts heat at 200 W/m·K (115.6 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-H conducts electricity at 48 % 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-H 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-H's machinability is fair (50/100, better than 69% of copper alloy grades); weldability fair (35/100); formability poor (30/100).
Common Calculations5
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-H
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-H — frequently asked
What is C18000-H used for?
C18000-H 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-H?
C18000-H has a typical yield strength of 585 MPa (84.8 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 93% of copper alloy grades. Strength varies by condition: see the 3 listed tempers.
Is C18000-H easy to machine?
Reasonably — machinability is rated fair (50/100, better than 69% 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-H 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-H?
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-H 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-H?
C18000-H is rated for continuous use to about 400°C (752 °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-H?
Yes — C18000-H 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.