Copper Alloy C65500-H08
Supply condition
UNS C65500 · ASTM B98, B96 · EN CuSi3Mn, CW116C
H08 = spring hard
Spring temper wire for marine springs, meshes and fasteners needing high elastic limit.
Values for the H08 condition
Other C65500 tempers and conditions
C65500 is listed in 10 conditions; see the grade overview at C65500.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Fully softened, coarse-grain C65500 with the lowest strength and highest ductility of the annealed tempers, intended for severe cold forming and deep drawing. | 150 | 395 | 62 | 76 HB | 7 % IACS |
ODefault Annealed | Most stocked condition for deep drawing, spinning, severe bending and welded fabrication. | 165 | 400 | 60 | 78 HB | 7 % IACS |
Light annealed | Fine-grain (≈0.025 mm) light anneal of C65500 that restores most ductility while keeping strength and hardness slightly above the fully soft state. | 170 | 415 | 55 | 85 HB | 7 % IACS |
As hot forged and air cooled | Hot-forged C65500 silicon bronze cooled in air, giving a recrystallised structure with moderate strength, good ductility and excellent weldability. | 175 | 415 | 35 | 95 HB | 7 % IACS |
As hot rolled | Pick for large extruded sections, forging stock and weld-fabricated parts where no temper control is needed. | 190 | 420 | 50 | 90 HB | 7 % IACS |
Quarter hard | Light cold work when moderate strength must be combined with continued bending/forming. | 275 | 470 | 35 | 120 HB | 6.9 % IACS |
Half hard | General-purpose strength/ductility compromise for bolts, screws, marine shafting and machined parts. | 345 | 540 | 22 | 150 HB | 7 % IACS |
Full hard | Choose for maximum strength in rod, wire and fasteners where little further forming is required. | 450 | 660 | 13 | 185 HB | 7 % IACS |
Extra hard | Heavily drawn wire and strip for springy clips and high-strength small sections. | 550 | 740 | 8 | 19 HRC | 6.8 % IACS |
H08This page Spring hard | Spring temper wire for marine springs, meshes and fasteners needing high elastic limit. | 650 | 830 | 5 | 21 HRC | 6.7 % IACS |
What is C65500-H08?
C65500-H08 is C65500 supplied in the H08 condition — spring temper wire for marine springs, meshes and fasteners needing high elastic limit. C65500-H08 has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 103 GPa (14.9 Msi). C65500-H08 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). O is the default condition FabDigit quotes; H08 is available on request or by drawing note.
Advantages
- High strength — 650 MPa (94.3 ksi), better than 96% of copper alloy grades
- Readily welded — 78/100, better than 91% of copper alloy grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 100% of copper alloy grades
- Limited ductility — 5%, worse than 93% of copper alloy grades
- Low electrical conductivity — 6.7 % IACS, worse than 89% of copper alloy grades
- Poor heat conductor — 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 88% of copper alloy grades
C65500-H08 properties
Typical room-temperature values for C65500-H08; 21 are specific to this condition. Other listed values are C65500 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C65500-H08 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).
Mechanical13
C65500-H08 has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 5% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C65500-H08 is rated for continuous service to 120°C (248 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 88% of copper alloy grades. Thermal expansion is 18 µm/m·K (10 µin/in·°F).
Electrical3
C65500-H08 conducts electricity at 6.7 % IACS, worse than 89% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C65500-H08 takes about 60 MJ of energy and emits 4 kg of CO₂ — more than 69% of copper alloy grades. Typical recycled content is 40%.
Manufacturability8
C65500-H08's machinability is fair (38/100, better than 55% of copper alloy grades); weldability very good (78/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C65500-H08
Is C65500 easy to machine?
Rated only ~30 % of free-cutting brass — gummy and work-hardening; use sharp positive-rake tools, rigid setups, moderate speed with generous coolant and avoid dwell.
Can C65500 be welded?
One of the best-welding copper alloys: GTAW/GMAW with ERCuSi-A filler, no preheat on thin sections, keep interpass low and avoid overheating to limit Si oxide film; brazing and silver soldering also good, resistance welding fair.
Can C65500 be formed, bent or molded?
Excellent cold formability in O temper (deep draw, spin, roll thread, cold head); hot work 700–875 °C only, since Si narrows the hot ductility window; anneal 480–700 °C and quench or air cool.
What surface finishes work on C65500?
Takes a bright mechanical polish and accepts statuary/brown chemical patinas, oxidizing dips and clear lacquer; electroplates (Ni, Cr) readily after activation — anodizing is not applicable.
C65500 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 | 2.8 – 3.8 | 3.1 |
| Mn | 0.5 – 1.3 | 0.9 |
| Fe | ≤ 0.8 | |
| Zn | ≤ 1.5 | |
| NiNi + Co, max | ≤ 0.6 | |
| Sn | ≤ 0.6 | |
| Pb | ≤ 0.05 | |
| Curemainder, 94.8 % min incl. Ag | ≥ 94.8 (balance) |
C65500-H08 — frequently asked
What is C65500-H08 used for?
C65500-H08 is typically used for silicon bronze fasteners and bolts, propeller shafts, chemical process vessels, anchor chain, underwater structural hardware and welding filler rod. In short: heavy marine structural bronze.
What is the yield strength of C65500-H08?
C65500-H08 has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 96% of copper alloy grades. Strength varies by condition: see the 10 listed tempers.
Is C65500-H08 easy to machine?
Not especially — machinability is rated fair (38/100, better than 55% of copper alloy grades). Rated only ~30 % of free-cutting brass — gummy and work-hardening; use sharp positive-rake tools, rigid setups, moderate speed with generous coolant and avoid dwell.
Can C65500-H08 be welded?
Yes — weldability is rated very good (78/100). One of the best-welding copper alloys: GTAW/GMAW with ERCuSi-A filler, no preheat on thin sections, keep interpass low and avoid overheating to limit Si oxide film; brazing and silver soldering also good, resistance welding fair.
What surface finishes work on C65500-H08?
Takes a bright mechanical polish and accepts statuary/brown chemical patinas, oxidizing dips and clear lacquer; electroplates (Ni, Cr) readily after activation — anodizing is not applicable.
Can C65500-H08 be formed, bent or molded?
Excellent cold formability in O temper (deep draw, spin, roll thread, cold head); hot work 700–875 °C only, since Si narrows the hot ductility window; anneal 480–700 °C and quench or air cool.
What is the maximum service temperature of C65500-H08?
C65500-H08 is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C65500-O and C65500-H08?
O is the default condition — most stocked condition for deep drawing, spinning, severe bending and welded fabrication. H08: spring temper wire for marine springs, meshes and fasteners needing high elastic limit. Yield strength is 165 MPa in O versus 650 MPa in H08.
Can FabDigit make parts in C65500-H08?
Yes — C65500-H08 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B98/B98M Copper-Silicon Alloy Rod, Bar and Shapes — ASTM International (2019)
- ASTM B96/B96M Copper-Silicon Alloy Plate, Sheet, Strip and Bar — ASTM International (2016)
- EN 12163/12167 CuSi3Mn (CW116C) — CEN (2016)
- C65500 alloy datasheet (properties, tempers, machinability) — Copper Development Association (copper.org) (2024)
- ASM Handbook Vol.2 — Properties of Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
- GB/T 5231 / GB/T 13808 QSi3-1 — (SAC) (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.