Copper Alloy C65500 · heat-treated state
Copper Alloy C65500-M10
Properties of the M10 condition, compared with the other C65500 tempers.
Hot-forged C65500 silicon bronze cooled in air, giving a recrystallised structure with moderate strength, good ductility and excellent weldability.
What is C65500-M10?
C65500-M10 is C65500 heat treated to M10 — hot-forged C65500 silicon bronze cooled in air, giving a recrystallised structure with moderate strength, good ductility and excellent weldability. C65500-M10 has a yield strength of 175 MPa (25.4 ksi) and a tensile strength of 415 MPa (60.2 ksi) — weaker than 59% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 103 GPa (14.9 Msi). C65500-M10 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; M10 is available on request or by drawing note.
Advantages
- Readily welded — 90/100, better than 98% of copper alloy grades
- Ductile — tolerates forming and impact — 35%, better than 79% of copper alloy grades
- Forms and bends easily — 70/100, better than 78% of copper alloy grades
Limitations
- Poor heat conductor — 36 W/m·K (20.8 BTU/hr·ft·°F), worse than 86% of copper alloy grades
- Low electrical conductivity — 7 % IACS, worse than 86% of copper alloy grades
C65500-M10 properties
Typical room-temperature values for C65500-M10 — 37 properties are specific to this condition; the rest are grade-level values shared by every C65500 temper. Each bar shows where the value sits among the copper alloy grades in FabDigit's library — further right is higher.
Physical3
C65500-M10 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-M10 has a yield strength of 175 MPa (25.4 ksi) and a tensile strength of 415 MPa (60.2 ksi) — weaker than 59% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal6
C65500-M10 is rated for continuous service to 200°C (392 °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 µm/m·K (10 µin/in·°F).
Electrical3
C65500-M10 conducts electricity at 7 % IACS, worse than 86% 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-M10 takes about 55 MJ of energy and emits 3.5 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 40%.
Manufacturability8
C65500-M10's machinability is poor (32/100, worse than 56% of copper alloy grades); weldability excellent (90/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other C65500 tempers and conditions
C65500 is also supplied in 9 other conditions. The full side-by-side table is on the C65500 overview.
- ODefaultMost stocked condition for deep drawing, spinning, severe bending and welded fabrication.165 MPa yield · 78 HB
- H08Spring temper wire for marine springs, meshes and fasteners needing high elastic limit.650 MPa yield · 97 HRB
- H06Heavily drawn wire and strip for springy clips and high-strength small sections.550 MPa yield · 210 HB
- H04Choose for maximum strength in rod, wire and fasteners where little further forming is required.450 MPa yield · 185 HB
- H02General-purpose strength/ductility compromise for bolts, screws, marine shafting and machined parts.345 MPa yield · 150 HB
- H01Light cold work when moderate strength must be combined with continued bending/forming.275 MPa yield · 120 HB
- M10Hot-forged C65500 silicon bronze cooled in air, giving a recrystallised structure with moderate strength, good ductility and excellent weldability.175 MPa yield · 95 HB
- O50Fine-grain (≈0.025 mm) light anneal of C65500 that restores most ductility while keeping strength and hardness slightly above the fully soft state.170 MPa yield · 85 HB
- O60Fully softened, coarse-grain C65500 with the lowest strength and highest ductility of the annealed tempers, intended for severe cold forming and deep drawing.150 MPa yield · 76 HB
Working with C65500-M10
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-M10 — frequently asked
What is C65500-M10 used for?
C65500-M10 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-M10?
C65500-M10 has a typical yield strength of 175 MPa (25.4 ksi) and a tensile strength of 415 MPa (60.2 ksi) — weaker than 59% of copper alloy grades. Strength varies by condition: see the 10 listed tempers.
Is C65500-M10 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 56% 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-M10 be welded?
Yes — weldability is rated excellent (90/100). 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-M10?
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-M10 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-M10?
C65500-M10 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 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-M10?
Yes — C65500-M10 is available for CNC machining and sheet metal with instant online pricing. 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.