Copper Alloy C63800-H08
Supply condition · default condition
UNS C63800 · ASTM B105
H08 = spring hard
Default stocked strip/wire temper: highest practical combination of spring properties, relaxation resistance and corrosion resistance.
Values for the H08 condition
Other C63800 tempers and conditions
C63800 is listed in 9 conditions; see the grade overview at C63800.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Softest supply condition for deep drawing or severe forming before final aging/work hardening. | 260 | 550 | 40 | 83 HRB | 10 % IACS |
Annealed | Standard annealed strip or wire for forming and subsequent cold-work strengthening. | 290 | 570 | 35 | 86 HRB | 10 % IACS |
Quarter hard | Light cold work when moderate strength must be combined with continued bending/forming ability. | 550 | 655 | 15 | 92 HRB | — |
Half hard | General-purpose strength/formability compromise for stamped hardware and contacts. | 650 | 725 | 10 | 95 HRB | — |
Three-quarter hard | Intermediate step between half and full hard for parts needing higher yield with a little bend allowance. | 690 | 760 | 8 | 97 HRB | — |
Full hard | Most common structural hard temper for fasteners, washers and flat stampings with mild forming. | 740 | 795 | 6 | 22 HRC | — |
Extra hard | High-yield temper for flat springs and contacts formed only along the grain with generous bend radii. | 810 | 860 | 5 | 24 HRC | — |
H08DefaultThis page Spring hard | Default stocked strip/wire temper: highest practical combination of spring properties, relaxation resistance and corrosion resistance. | 855 | 895 | 4 | 25 HRC | 10 % IACS |
Extra spring hard | Maximum-strength temper for flat springs and connector fingers loaded essentially in the rolled direction only. | 895 | 930 | 3 | 27 HRC | — |
What is C63800-H08?
C63800-H08 is C63800 supplied in the H08 condition — default stocked strip/wire temper: highest practical combination of spring properties, relaxation resistance and corrosion resistance. C63800-H08 has a yield strength of 855 MPa (124 ksi) and a tensile strength of 895 MPa (130 ksi) — stronger than 98% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 124 GPa (18 Msi). C63800-H08 has a density of 7.69 g/cm³ (0.278 lb/in³), lighter than 90% of copper alloy grades. It melts at 1,030°C (1,886 °F).
Advantages
- High strength — 855 MPa (124 ksi), better than 98% of copper alloy grades
- Lightweight — 7.69 g/cm³ (0.278 lb/in³), better than 90% of copper alloy grades
- Good corrosion resistance — 74/100, better than 88% of copper alloy grades
Limitations
- Limited ductility — 4%, worse than 96% of copper alloy grades
- Poor heat conductor — 44.6 W/m·K (25.8 BTU/hr·ft·°F), worse than 78% of copper alloy grades
C63800-H08 properties
Typical room-temperature values for C63800-H08; 12 are specific to this condition. Other listed values are C63800 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C63800-H08 has a density of 7.69 g/cm³ (0.278 lb/in³), lighter than 90% of copper alloy grades. It melts at 1,030°C (1,886 °F).
Mechanical13
C63800-H08 has a yield strength of 855 MPa (124 ksi) and a tensile strength of 895 MPa (130 ksi) — stronger than 98% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 124 GPa (18 Msi).
Thermal5
C63800-H08 is rated for continuous service to 200°C (392 °F). It conducts heat at 44.6 W/m·K (25.8 BTU/hr·ft·°F), worse than 78% of copper alloy grades. Thermal expansion is 16.9 µm/m·K (9.39 µin/in·°F).
Electrical3
C63800-H08 conducts electricity at 10 % IACS, worse than 74% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (74/100), better than 88% of copper alloy grades.
Sustainability4
Producing a kilogram of C63800-H08 takes about 57 MJ of energy and emits 3.6 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
C63800-H08's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability fair (45/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C63800-H08
Is C63800 easy to machine?
Rated about 30 % of free-cutting brass — gummy and abrasive; use sharp carbide, positive rake, moderate speed and generous coolant, and expect built-up edge in annealed temper.
Can C63800 be welded?
GTAW/GMAW and resistance welding are feasible with aluminum-bronze filler and oxide removal, but heat destroys the cold-worked strength, so joints are usually mechanical or soldered.
Can C63800 be formed, bent or molded?
Form in O60/O61 or ¼-hard; hard and spring tempers need bend radii of 2–5 t and preferably good-way (transverse) bends, with stress relief at ~230–290 °C after forming.
What surface finishes work on C63800?
Takes a bright gold-bronze polish and accepts tin, nickel or gold plating after alkaline/acid cleaning to strip the tenacious Al-Si oxide; anodizing is not applicable.
C63800 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 |
|---|---|---|
| Al | 2.5 – 3.1 | 2.8 |
| Si | 1.5 – 2.1 | 1.8 |
| Co | 0.25 – 0.55 | 0.4 |
| Sn | ≤ 0.2 | — |
| Zn | ≤ 0.8 | — |
| Fe | ≤ 0.2 | — |
| Mn | ≤ 0.1 | — |
| Pb | ≤ 0.05 | — |
| Cuincluding Ag; remainder | ≥ 95 (balance) | — |
C63800-H08 — frequently asked
What is C63800-H08 used for?
C63800-H08 is typically used for springs, fasteners and electrical/electronic spring contacts. In short: spring-temper aluminum bronze; beryllium-free spring alternative; low formability, high strength.
What is the yield strength of C63800-H08?
C63800-H08 has a typical yield strength of 855 MPa (124 ksi) and a tensile strength of 895 MPa (130 ksi) — stronger than 98% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C63800-H08 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% of copper alloy grades). Rated about 30 % of free-cutting brass — gummy and abrasive; use sharp carbide, positive rake, moderate speed and generous coolant, and expect built-up edge in annealed temper.
Can C63800-H08 be welded?
With care — weldability is rated fair (45/100). GTAW/GMAW and resistance welding are feasible with aluminum-bronze filler and oxide removal, but heat destroys the cold-worked strength, so joints are usually mechanical or soldered.
What surface finishes work on C63800-H08?
Takes a bright gold-bronze polish and accepts tin, nickel or gold plating after alkaline/acid cleaning to strip the tenacious Al-Si oxide; anodizing is not applicable.
Can C63800-H08 be formed, bent or molded?
Form in O60/O61 or ¼-hard; hard and spring tempers need bend radii of 2–5 t and preferably good-way (transverse) bends, with stress relief at ~230–290 °C after forming.
What is the maximum service temperature of C63800-H08?
C63800-H08 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 C63800-H08 and C63800-O60?
H08 is the default condition — default stocked strip/wire temper: highest practical combination of spring properties, relaxation resistance and corrosion resistance. O60: softest supply condition for deep drawing or severe forming before final aging/work hardening. Yield strength is 855 MPa in H08 versus 260 MPa in O60.
Sources
- ASTM B105 — Hard-Drawn Copper Alloy Wires for Electric Conductors — ASTM International (2018)
- CDA Alloy Datasheet C63800 (UNS C63800) — 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)
- Spring-metal strip alloy data (aluminum-silicon bronze 638) — Specialty copper strip producers (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.