Copper Alloy C70500-H04
Supply condition
UNS C70500 · ASTM B111
H04 = full hard
Choose for flat springs, clips and wear surfaces where only mild bending is required after forming.
Values for the H04 condition
Other C70500 tempers and conditions
C70500 is listed in 7 conditions; see the grade overview at C70500.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
O61Default Annealed | Standard condition for condenser and heat-exchanger tube that must be expanded/rolled into tubesheets or U-bent. | 105 | 275 | 40 | 55 HB | 25 % IACS |
Drawn and stress-relieved tube | Use where residual stress from drawing must be reduced (ammonia-bearing atmospheres, U-bend legs) while keeping drawn strength. | 190 | 305 | 28 | 72 HB | 24.5 % IACS |
Light-drawn tube | Pick when straight tube with better handling stiffness and dimensional stability is needed but some expandability must remain. | 200 | 310 | 25 | 75 HB | 24 % IACS |
Quarter hard | Flat-product temper for deep-drawn or formed parts needing more spring than fully soft strip. | 220 | 315 | 22 | 78 HB | 25 % IACS |
Half hard | General-purpose flat temper balancing formability with useful yield strength for brackets, sleeves and shells. | 280 | 350 | 14 | 92 HB | 24 % IACS |
Hard drawn | Highest-strength tube condition for pressure or structural tubing where no significant expansion or bending follows. | 350 | 400 | 8 | 105 HB | 24 % IACS |
H04This page Full hard | Choose for flat springs, clips and wear surfaces where only mild bending is required after forming. | 370 | 415 | 6 | 110 HB | 24 % IACS |
What is C70500-H04?
C70500-H04 is C70500 supplied in the H04 condition — choose for flat springs, clips and wear surfaces where only mild bending is required after forming. C70500-H04 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 75% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 124 GPa (18 Msi). C70500-H04 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,090°C (1,994 °F). O61 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- Readily welded — 75/100, better than 89% of copper alloy grades
- High strength — 370 MPa (53.7 ksi), better than 75% of copper alloy grades
Limitations
- Limited ductility — 6%, worse than 89% of copper alloy grades
C70500-H04 properties
Typical room-temperature values for C70500-H04; 19 are specific to this condition. Other listed values are C70500 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C70500-H04 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,090°C (1,994 °F).
Mechanical12
C70500-H04 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 75% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 124 GPa (18 Msi).
Thermal6
C70500-H04 is rated for continuous service to 200°C (392 °F). It conducts heat at 88 W/m·K (50.8 BTU/hr·ft·°F), better than 53% of copper alloy grades. Thermal expansion is 17.1 µm/m·K (9.5 µin/in·°F).
Electrical3
C70500-H04 conducts electricity at 24 % IACS, better than 57% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C70500-H04 takes about 60 MJ of energy and emits 4 kg of CO₂ — more than 69% of copper alloy grades. Typical recycled content is 35%.
Manufacturability6
C70500-H04's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability very good (75/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C70500-H04
Is C70500 easy to machine?
Gummy and work-hardening like all cupronickels — use sharp positive-rake carbide, ~60–100 m/min, heavy feed and generous coolant to avoid built-up edge; rating only about 20 % of free-cutting brass.
Can C70500 be welded?
Readily GTAW/GMAW welded with ERCuNi (70/30) filler under argon, no preheat and no post-weld heat treatment; keep joints clean and sulphur/lead-free to avoid hot cracking, and avoid oxyacetylene.
Can C70500 be formed, bent or molded?
Excellent cold formability in O61 — bends, expands and U-bends well; interanneal near 700–800 °C for heavy reductions and stress-relieve drawn tube if ammonia exposure is expected.
What surface finishes work on C70500?
Solders and brazes easily with proper flux; not anodizable — finish by pickling/passivation, mechanical polishing or tin/nickel plating, and expect a protective brown-green patina in seawater service.
C70500 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 |
|---|---|---|
| Ninickel (may be reported as Ni+Co); nominal 2 % low-nickel cupronickel | 1.5 – 2.5 | 2 |
| Feiron addition for impingement resistance; verify exact limits against current CDA/ASTM registration | 0.1 – 1 | 0.5 |
| Mndeoxidiser / sulphur scavenger | 0 – 1 | 0.4 |
| Znimpurity limit | ≤ 0.5 | — |
| Pbimpurity limit | ≤ 0.05 | — |
| Cimpurity limit | ≤ 0.05 | — |
| Simpurity limit | ≤ 0.02 | — |
| Curemainder, approximately 96–98 % | balance | — |
C70500-H04 — frequently asked
What is C70500-H04 used for?
C70500-H04 is typically used for condenser tubing, heat exchanger tubes and low-cost marine piping. In short: cheapest cupronickel tube grade; softer than 90/10 Cu-Ni; high formability, low machinability.
What is the yield strength of C70500-H04?
C70500-H04 has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 75% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C70500-H04 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy and work-hardening like all cupronickels — use sharp positive-rake carbide, ~60–100 m/min, heavy feed and generous coolant to avoid built-up edge; rating only about 20 % of free-cutting brass.
Can C70500-H04 be welded?
Yes — weldability is rated very good (75/100). Readily GTAW/GMAW welded with ERCuNi (70/30) filler under argon, no preheat and no post-weld heat treatment; keep joints clean and sulphur/lead-free to avoid hot cracking, and avoid oxyacetylene.
What surface finishes work on C70500-H04?
Solders and brazes easily with proper flux; not anodizable — finish by pickling/passivation, mechanical polishing or tin/nickel plating, and expect a protective brown-green patina in seawater service.
Can C70500-H04 be formed, bent or molded?
Excellent cold formability in O61 — bends, expands and U-bends well; interanneal near 700–800 °C for heavy reductions and stress-relieve drawn tube if ammonia exposure is expected.
What is the maximum service temperature of C70500-H04?
C70500-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 C70500-O61 and C70500-H04?
O61 is the default condition — standard condition for condenser and heat-exchanger tube that must be expanded/rolled into tubesheets or U-bent. H04: choose for flat springs, clips and wear surfaces where only mild bending is required after forming. Yield strength is 105 MPa in O61 versus 370 MPa in H04.
Sources
- ASTM B111/B111M — Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock — ASTM International (2021)
- ASTM B543 — Welded Copper and Copper-Alloy Heat Exchanger Tube — ASTM International (2020)
- CDA/UNS Copper Alloy Property Data (C705xx copper-nickels) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Copper-Nickel Alloys: Properties and Application Guidance — Nickel Institute / CDA UK (2016)
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.