Copper Alloy C65400-H04
Supply condition · default condition
UNS C65400 · ASTM B98
H04 = full hard
Most commonly stocked condition — high strength strip, rod and fastener stock with usable bend performance.
Values for the H04 condition
Other C65400 tempers and conditions
C65400 is listed in 9 conditions; see the grade overview at C65400.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for deep drawing, severe forming or as the starting stock for subsequent cold work. | 205 | 455 | 40 | 62 HRB | — |
Quarter hard | Pick when moderate strength must be combined with substantial remaining bendability. | 415 | 505 | 20 | 140 HB | 7 % IACS |
Half hard | General-purpose strip/rod temper balancing strength with 90° bend capability. | 525 | 585 | 10 | 88 HRB | — |
Three-quarter hard | Pick for structural parts and fasteners needing high strength with light forming only. | 570 | 620 | 8 | 11 HRC | 6.5 % IACS |
H04DefaultThis page Full hard | Most commonly stocked condition — high strength strip, rod and fastener stock with usable bend performance. | 620 | 660 | 5 | 93 HRB | — |
Extra hard | Pick for flat springs and clips where forming is limited to gentle radii in the good bend direction. | 690 | 720 | 4 | 18 HRC | 6 % IACS |
Spring hard | Standard spring temper for contacts, washers and retaining components with high elastic limit. | 725 | 760 | 3 | 19 HRC | 5.9 % IACS |
Extra spring hard | Pick when spring rate and elastic limit must exceed H08 and only flat or very gently formed parts are made. | 760 | 790 | 3 | 20 HRC | 5.8 % IACS |
Strain hardened, half hard | Highest strength condition offered — flat spring strip and wire where no appreciable forming is required. | 795 | 830 | 2 | 21 HRC | 5.7 % IACS |
What is C65400-H04?
C65400-H04 is C65400 supplied in the H04 condition — most commonly stocked condition — high strength strip, rod and fastener stock with usable bend performance. C65400-H04 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 95% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 117 GPa (17 Msi). C65400-H04 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 971°C (1,780 °F).
Advantages
- High strength — 620 MPa (89.9 ksi), better than 95% of copper alloy grades
- Readily welded — 80/100, better than 93% of copper alloy grades
- Good corrosion resistance — 76/100, better than 91% of copper alloy grades
Limitations
- Limited ductility — 5%, worse than 93% of copper alloy grades
- Low electrical conductivity — 6 % IACS, worse than 93% of copper alloy grades
- Limited service temperature — 175°C (347 °F), worse than 92% of copper alloy grades
- Poor heat conductor — 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 86% of copper alloy grades
C65400-H04 properties
Typical room-temperature values for C65400-H04; 11 are specific to this condition. Other listed values are C65400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C65400-H04 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 971°C (1,780 °F).
Mechanical12
C65400-H04 has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 95% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C65400-H04 is rated for continuous service to 175°C (347 °F). It conducts heat at 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 86% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C65400-H04 conducts electricity at 6 % IACS, worse than 93% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (76/100), better than 91% of copper alloy grades.
Sustainability4
Producing a kilogram of C65400-H04 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
C65400-H04's machinability is poor (33/100, worse than 53% of copper alloy grades); weldability very good (80/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C65400-H04
Is C65400 easy to machine?
Gummy, stringy chips — use sharp positive-rake tools, high speed with light feed and generous coolant; rating ~30 % of AISI 1212, so allow extra tool life budget vs free-cutting brass.
Can C65400 be welded?
Excellent with GTAW/GMAW using ERCuSi-A filler and low interpass temperature; resistance and oxyacetylene welding are usable, but keep heat input low to limit silicide segregation.
Can C65400 be formed, bent or molded?
Very high work-hardening rate — form in O61/H01 with interstage anneals near 500–600 °C; hard and spring tempers should be bent with the grain and generous radii.
What surface finishes work on C65400?
Takes a bright mechanical polish and chemical patination; no anodizing — plate with Ni, Sn or Ag over a suitable strike, and avoid ammonia-containing cleaners on cold-worked parts.
C65400 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 |
|---|---|---|
| Si | 2.7 – 3.4 | 3 |
| Sn | 1.5 – 2 | 1.8 |
| Cr | 0.01 – 0.12 | 0.05 |
| Zn | ≤ 0.5 | — |
| Pbimpurity limit | ≤ 0.05 | — |
| CuCu + Ag remainder | balance | — |
C65400-H04 — frequently asked
What is C65400-H04 used for?
C65400-H04 is typically used for valve stems, structural fasteners and marine hardware. In short: high-strength silicon bronze; 620 MPa yield in bronze; weldable structural fastener alloy.
What is the yield strength of C65400-H04?
C65400-H04 has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 660 MPa (95.7 ksi) — stronger than 95% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C65400-H04 easy to machine?
Not especially — machinability is rated poor (33/100, worse than 53% of copper alloy grades). Gummy, stringy chips — use sharp positive-rake tools, high speed with light feed and generous coolant; rating ~30 % of AISI 1212, so allow extra tool life budget vs free-cutting brass.
Can C65400-H04 be welded?
Yes — weldability is rated very good (80/100). Excellent with GTAW/GMAW using ERCuSi-A filler and low interpass temperature; resistance and oxyacetylene welding are usable, but keep heat input low to limit silicide segregation.
What surface finishes work on C65400-H04?
Takes a bright mechanical polish and chemical patination; no anodizing — plate with Ni, Sn or Ag over a suitable strike, and avoid ammonia-containing cleaners on cold-worked parts.
Can C65400-H04 be formed, bent or molded?
Very high work-hardening rate — form in O61/H01 with interstage anneals near 500–600 °C; hard and spring tempers should be bent with the grain and generous radii.
What is the maximum service temperature of C65400-H04?
C65400-H04 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C65400-H04 and C65400-O61?
H04 is the default condition — most commonly stocked condition — high strength strip, rod and fastener stock with usable bend performance. O61: pick for deep drawing, severe forming or as the starting stock for subsequent cold work. Yield strength is 620 MPa in H04 versus 205 MPa in O61.
Sources
- ASTM B98/B98M — Copper-Silicon Alloy Rod, Bar and Shapes — ASTM International (2020)
- CDA Alloy Datasheet C65400 (Standards & Properties) — Copper Development Association (2023)
- 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.