Copper Alloy C18900-H04
Supply condition · default condition
UNS C18900
H04 = full hard
Standard stocked condition for rod, wire and contact tips where maximum strength, hardness and wear resistance are needed.
Values for the H04 condition
Other C18900 tempers and conditions
C18900 is listed in 6 conditions; see the grade overview at C18900.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Choose for welding wire/rod, deep drawing, bending and any forming operation needing maximum ductility. | 95 | 275 | 45 | 55 HB | 47 % IACS |
As hot rolled | As-extruded/hot-worked mill condition for large rod and shapes that will be machined or further cold drawn. | 130 | 285 | 38 | 62 HB | 46 % IACS |
Quarter hard | Light cold work for parts that still need moderate bending but higher strength than annealed. | 230 | 315 | 25 | 80 HB | 46 % IACS |
Half hard | General-purpose balance of strength and residual formability for machined and formed contact parts. | 305 | 355 | 15 | 98 HB | 45 % IACS |
H04DefaultThis page Full hard | Standard stocked condition for rod, wire and contact tips where maximum strength, hardness and wear resistance are needed. | 370 | 405 | 8 | 115 HB | 45 % IACS |
Spring hard | Heavily drawn wire condition for springy contacts and high-strength conductor wire; very limited ductility. | 425 | 455 | 4 | 130 HB | 44 % IACS |
What is C18900-H04?
C18900-H04 is C18900 supplied in the H04 condition — standard stocked condition for rod, wire and contact tips where maximum strength, hardness and wear resistance are needed. C18900-H04 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 405 MPa (58.7 ksi) — stronger than 75% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 117 GPa (17 Msi). C18900-H04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,030°C (1,886 °F).
Advantages
- Readily welded — 80/100, better than 93% of copper alloy grades
- High electrical conductivity — 45 % IACS, better than 77% of copper alloy grades
- High strength — 370 MPa (53.7 ksi), better than 75% of copper alloy grades
- Conducts heat well — 180 W/m·K (104 BTU/hr·ft·°F), better than 75% of copper alloy grades
Limitations
- Limited ductility — 8%, worse than 83% of copper alloy grades
C18900-H04 properties
Typical room-temperature values for C18900-H04; 20 are specific to this condition. Other listed values are C18900 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C18900-H04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,030°C (1,886 °F).
Mechanical14
C18900-H04 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 405 MPa (58.7 ksi) — stronger than 75% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C18900-H04 is rated for continuous service to 200°C (392 °F). It conducts heat at 180 W/m·K (104 BTU/hr·ft·°F), better than 75% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C18900-H04 conducts electricity at 45 % IACS, better than 77% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C18900-H04 takes about 57 MJ of energy and emits 3.7 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
C18900-H04's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability very good (80/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C18900-H04
Is C18900 easy to machine?
Gummy like most non-leaded coppers — use sharp positive-rake carbide, high speed, generous feed and flood coolant; rating ≈ 20 % of AISI 1212 and best in H02/H04 tempers.
Can C18900 be welded?
Readily joined by GTAW/GMAW with matching or ErCu/ErCuSi filler; preheat thick sections for the high thermal conductivity, and expect full loss of cold-worked strength in the HAZ.
Can C18900 be formed, bent or molded?
Excellent cold formability in O60 (deep draw, roll, bend); in H04 keep bend radii ≥ 2t and interanneal at 450–600 °C for severe work.
What surface finishes work on C18900?
Not anodisable; takes bright polish, Ni/Sn/Ag electroplate and chemical patina well — degrease thoroughly and pickle to remove the tenacious Si-bearing oxide before plating.
C18900 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 |
|---|---|---|
| Snsolid-solution strengthener | 0.6 – 0.9 | 0.75 |
| Sideoxidiser and strengthener | 0.1 – 0.3 | 0.2 |
| Mndeoxidiser / arc stabiliser in weld wire | 0.02 – 0.2 | 0.1 |
| Presidual | ≤ 0.05 | — |
| Feresidual | ≤ 0.05 | — |
| Pbresidual | ≤ 0.02 | — |
| CuCu + named elements ≥ 99.5 %; Ag counted as Cu | ≥ 98 (balance) | — |
C18900-H04 — frequently asked
What is C18900-H04 used for?
C18900-H04 is typically used for electrical connectors, fasteners requiring conductivity and marine hardware. In short: weldable silicon-bearing copper; strength with 45% IACS; marine-capable lightly alloyed copper.
What is the yield strength of C18900-H04?
C18900-H04 has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 405 MPa (58.7 ksi) — stronger than 75% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C18900-H04 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% of copper alloy grades). Gummy like most non-leaded coppers — use sharp positive-rake carbide, high speed, generous feed and flood coolant; rating ≈ 20 % of AISI 1212 and best in H02/H04 tempers.
Can C18900-H04 be welded?
Yes — weldability is rated very good (80/100). Readily joined by GTAW/GMAW with matching or ErCu/ErCuSi filler; preheat thick sections for the high thermal conductivity, and expect full loss of cold-worked strength in the HAZ.
What surface finishes work on C18900-H04?
Not anodisable; takes bright polish, Ni/Sn/Ag electroplate and chemical patina well — degrease thoroughly and pickle to remove the tenacious Si-bearing oxide before plating.
Can C18900-H04 be formed, bent or molded?
Excellent cold formability in O60 (deep draw, roll, bend); in H04 keep bend radii ≥ 2t and interanneal at 450–600 °C for severe work.
What is the maximum service temperature of C18900-H04?
C18900-H04 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C18900-H04 and C18900-O60?
H04 is the default condition — standard stocked condition for rod, wire and contact tips where maximum strength, hardness and wear resistance are needed. O60: choose for welding wire/rod, deep drawing, bending and any forming operation needing maximum ductility. Yield strength is 370 MPa in H04 versus 95 MPa in O60.
Sources
- UNS C18900 alloy data (Copper Development Association alloy database) — CDA / copper.org (2023)
- ASTM B224 – Classification of Coppers — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
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.