Copper Alloy C64710-M20
Finish state
UNS C64710 · ASTM B98
M20 = as hot rolled
Mill as-extruded bar before heat treatment; only for re-heat-treated or lightly loaded parts.
Values for the M20 condition
Other C64710 tempers and conditions
C64710 is listed in 9 conditions; see the grade overview at C64710.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Maximum ductility for deep forming, heading or bending before ageing. | 130 | 330 | 45 | 75 HB | 14 % IACS |
Solution heat treated | Supply condition for parts that will be formed/headed and then aged by the fabricator. | 150 | 350 | 45 | 80 HB | 10 % IACS |
M20This page As hot rolled | Mill as-extruded bar before heat treatment; only for re-heat-treated or lightly loaded parts. | 170 | 380 | 35 | 90 HB | 15 % IACS |
Half hard | Cold-drawn intermediate temper when moderate strength plus some formability is needed without ageing. | 380 | 470 | 15 | 140 HB | 13 % IACS |
TF00Default Solution heat treated and precipitation hardened | Standard stocked high-strength condition for marine bolts, studs, shafts and fittings. | 480 | 620 | 15 | 180 HB | 25 % IACS |
Full hard | Cold-drawn hard rod/wire for springs and screw-machine stock where no ageing furnace is available. | 480 | 550 | 9 | 160 HB | 13 % IACS |
Solution heat treated and cold worked, full hard | Cold-worked after solution treatment; intermediate stock for TH tempers or for high-strength unaged wire. | 490 | 560 | 10 | 165 HB | 11 % IACS |
TD02 and precipitation hardened | Moderate cold work before ageing for a strength/ductility balance above TF00. | 570 | 660 | 11 | 13 HRC | 25 % IACS |
TD04 and precipitation hardened | Highest-strength temper for heavily loaded bolts, pins and springs where ductility can be traded away. | 640 | 720 | 8 | 21 HRC | 25 % IACS |
What is C64710-M20?
C64710-M20 is C64710 supplied in the M20 condition — mill as-extruded bar before heat treatment; only for re-heat-treated or lightly loaded parts. C64710-M20 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 62% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 131 GPa (19 Msi). C64710-M20 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 1,055°C (1,931 °F). TF00 is the default condition FabDigit quotes; M20 is available on request or by drawing note.
Advantages
- Stiff — 131 GPa (19 Msi), better than 91% of copper alloy grades
- Readily welded — 75/100, better than 89% of copper alloy grades
- Good corrosion resistance — 72/100, better than 84% of copper alloy grades
- Ductile — tolerates forming and impact — 35%, better than 80% of copper alloy grades
Limitations
- Poor heat conductor — 30 W/m·K (17.3 BTU/hr·ft·°F), worse than 91% of copper alloy grades
C64710-M20 properties
Typical room-temperature values for C64710-M20; 20 are specific to this condition. Other listed values are C64710 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C64710-M20 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 1,055°C (1,931 °F).
Mechanical14
C64710-M20 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 62% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 131 GPa (19 Msi).
Thermal6
C64710-M20 is rated for continuous service to 200°C (392 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), worse than 91% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C64710-M20 conducts electricity at 15 % IACS, worse than 54% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (72/100), better than 84% of copper alloy grades.
Sustainability4
Producing a kilogram of C64710-M20 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 30%.
Manufacturability8
C64710-M20's machinability is poor (27/100, worse than 81% of copper alloy grades); weldability very good (75/100); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C64710-M20
Is C64710 easy to machine?
Rating ~30 % of C36000: use sharp positive-rake carbide, moderate speeds, generous coolant; chips are gummy in the solution-treated state so machine in TF00/TH04 for best finish.
Can C64710 be welded?
GTAW/GMAW with matching or Si-bronze filler is practical; keep heat input low and re-age critical joints because the HAZ loses precipitation strength.
Can C64710 be formed, bent or molded?
Head, bend and cold form in O60/TB00 then age; formability is limited once aged, and hot working is done around 750–870 °C.
What surface finishes work on C64710?
Not anodisable — polishes to a bright bronze lustre; tin, nickel or chromate/patina finishes are used, and passivation is unnecessary for marine service.
C64710 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 |
|---|---|---|
| NiNi+Co counted together in some registrations | 1.6 – 2.2 | 1.9 |
| Si | 0.4 – 0.8 | 0.6 |
| Zn | ≤ 0.5 | — |
| Fe | ≤ 0.2 | — |
| Mn | ≤ 0.2 | — |
| Sn | ≤ 0.2 | — |
| Pb | ≤ 0.05 | — |
| Cu≈96–97 %; composition limits close to C64700, verify against current CDA/ASTM B98 registration | balance | — |
C64710-M20 — frequently asked
What is C64710-M20 used for?
C64710-M20 is typically used for marine fasteners, high-strength bolts and corrosion-resistant fittings. In short: age-hardenable silicon bronze; weldable high-strength bronze; cold-headable fastener alloy.
What is the yield strength of C64710-M20?
C64710-M20 has a typical yield strength of 170 MPa (24.7 ksi) and a tensile strength of 380 MPa (55.1 ksi) — weaker than 62% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C64710-M20 easy to machine?
Not especially — machinability is rated poor (27/100, worse than 81% of copper alloy grades). Rating ~30 % of C36000: use sharp positive-rake carbide, moderate speeds, generous coolant; chips are gummy in the solution-treated state so machine in TF00/TH04 for best finish.
Can C64710-M20 be welded?
Yes — weldability is rated very good (75/100). GTAW/GMAW with matching or Si-bronze filler is practical; keep heat input low and re-age critical joints because the HAZ loses precipitation strength.
What surface finishes work on C64710-M20?
Not anodisable — polishes to a bright bronze lustre; tin, nickel or chromate/patina finishes are used, and passivation is unnecessary for marine service.
Can C64710-M20 be formed, bent or molded?
Head, bend and cold form in O60/TB00 then age; formability is limited once aged, and hot working is done around 750–870 °C.
What is the maximum service temperature of C64710-M20?
C64710-M20 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 C64710-TF00 and C64710-O60?
TF00 is the default condition — standard stocked high-strength condition for marine bolts, studs, shafts and fittings. O60: maximum ductility for deep forming, heading or bending before ageing. Yield strength is 480 MPa in TF00 versus 130 MPa in O60.
Sources
- ASTM B98/B98M — Copper-Silicon Alloy Rod, Bar and Shapes — ASTM International (2020)
- CDA/UNS Copper Alloy Datasheets (C647xx nickel-silicon bronzes) — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion: Materials (copper alloys in seawater) — ASM International (2005)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM International (2019)
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.