Copper Alloy C65400-H06
Supply condition
UNS C65400 · ASTM B98
H06 = extra hard
Pick for flat springs and clips where forming is limited to gentle radii in the good bend direction.
Values for the H06 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 |
H04Default Full hard | Most commonly stocked condition — high strength strip, rod and fastener stock with usable bend performance. | 620 | 660 | 5 | 93 HRB | — |
H06This page 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-H06?
C65400-H06 is C65400 supplied in the H06 condition — pick for flat springs and clips where forming is limited to gentle radii in the good bend direction. C65400-H06 has a yield strength of 690 MPa (100 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi). C65400-H06 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). H04 is the default condition FabDigit quotes; H06 is available on request or by drawing note.
Advantages
- High strength — 690 MPa (100 ksi), better than 96% of copper alloy grades
- Good corrosion resistance — 75/100, better than 90% of copper alloy grades
- Readily welded — 75/100, better than 89% of copper alloy grades
Limitations
- Limited ductility — 4%, worse than 96% of copper alloy grades
- Low electrical conductivity — 6 % IACS, worse than 93% of copper alloy grades
- Limited service temperature — 165°C (329 °F), worse than 92% of copper alloy grades
- Poor heat conductor — 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 88% of copper alloy grades
C65400-H06 properties
Typical room-temperature values for C65400-H06; 22 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-H06 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-H06 has a yield strength of 690 MPa (100 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C65400-H06 is rated for continuous service to 165°C (329 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 88% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C65400-H06 conducts electricity at 6 % IACS, worse than 93% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (75/100), better than 90% of copper alloy grades.
Sustainability4
Producing a kilogram of C65400-H06 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-H06's machinability is poor (34/100, worse than 53% of copper alloy grades); weldability very good (75/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C65400-H06
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-H06 — frequently asked
What is C65400-H06 used for?
C65400-H06 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-H06?
C65400-H06 has a typical yield strength of 690 MPa (100 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 96% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C65400-H06 easy to machine?
Not especially — machinability is rated poor (34/100, 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-H06 be welded?
Yes — weldability is rated very good (75/100). 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-H06?
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-H06 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-H06?
C65400-H06 is rated for continuous use to about 165°C (329 °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.