Copper Alloy C74000-M20
Finish state
UNS C74000
M20 = as hot rolled
Pick for heavier hot-rolled plate/bar stock where a soft, machinable, weldable condition is enough.
Values for the M20 condition
Other C74000 tempers and conditions
C74000 is listed in 8 conditions; see the grade overview at C74000.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick for deep drawing, spinning and severe bending of decorative parts. | 120 | 345 | 45 | 75 HB | — |
M20This page As hot rolled | Pick for heavier hot-rolled plate/bar stock where a soft, machinable, weldable condition is enough. | 140 | 360 | 40 | 85 HB | — |
Quarter hard | Pick when moderate stiffness is needed but the part still requires appreciable bending or forming. | 275 | 415 | 25 | 120 HB | — |
Light drawn | Pick for drawn rod, wire or tube needing straightness and moderate strength with some upsetting ability. | 330 | 450 | 18 | 132 HB | 9 % IACS |
H02Default Half hard | Default stocked strip/sheet temper — best all-round balance of strength, bendability and polished appearance. | 380 | 470 | 12 | 145 HB | — |
Full hard | Pick for flat springs, contacts and stamped parts needing high strength with only gentle bends. | 490 | 550 | 4 | 175 HB | — |
Extra hard | Pick for maximum stiffness and spring-back in flat springs and clips where forming is minimal. | 550 | 620 | 2.5 | 195 HB | — |
Spring hard | Pick for high-load flat springs and contact fingers where practically no forming is required. | 610 | 670 | 2 | 14 HRC | 8.5 % IACS |
What is C74000-M20?
C74000-M20 is C74000 supplied in the M20 condition — pick for heavier hot-rolled plate/bar stock where a soft, machinable, weldable condition is enough. C74000-M20 has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 360 MPa (52.2 ksi) — weaker than 74% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 125 GPa (18.1 Msi). C74000-M20 has a density of 8.75 g/cm³ (0.316 lb/in³), lighter than 51% of copper alloy grades. It melts at 1,010°C (1,850 °F). H02 is the default condition FabDigit quotes; M20 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 97% of copper alloy grades
- High service temperature — 300°C (572 °F), better than 85% of copper alloy grades
- Ductile — tolerates forming and impact — 40%, better than 84% of copper alloy grades
- Forms and bends easily — 80/100, better than 83% of copper alloy grades
Limitations
- High embodied carbon — 5.2 kg CO₂/kg, worse than 88% of copper alloy grades
- Low electrical conductivity — 9 % IACS, worse than 78% of copper alloy grades
- Poor heat conductor — 45 W/m·K (26 BTU/hr·ft·°F), worse than 76% of copper alloy grades
C74000-M20 properties
Typical room-temperature values for C74000-M20; 10 are specific to this condition. Other listed values are C74000 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C74000-M20 has a density of 8.75 g/cm³ (0.316 lb/in³), lighter than 51% of copper alloy grades. It melts at 1,010°C (1,850 °F).
Mechanical12
C74000-M20 has a yield strength of 140 MPa (20.3 ksi) and a tensile strength of 360 MPa (52.2 ksi) — weaker than 74% of copper alloy grades. Elongation at break is 40% and the elastic modulus is 125 GPa (18.1 Msi).
Thermal6
C74000-M20 is rated for continuous service to 300°C (572 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), worse than 76% of copper alloy grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
C74000-M20 conducts electricity at 9 % IACS, worse than 78% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C74000-M20 takes about 75 MJ of energy and emits 5.2 kg of CO₂ — more than 88% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C74000-M20's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability good (55/100); formability very good (80/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C74000-M20
Is C74000 easy to machine?
Gummy and abrasive on tooling (≈20 % of free-cutting brass) — use sharp positive-rake carbide, high speed with light feeds and copious lubricant; consider leaded C79300 if turning volume is high.
Can C74000 be welded?
Best joined by GTAW/GMAW with Cu-Ni filler or by silver brazing/soldering; resistance welding is fair and oxyacetylene welding risks zinc fume loss — ventilate and avoid overheating.
Can C74000 be formed, bent or molded?
Annealed and quarter-hard stock deep-draws and coins very well; interstage anneal at 600–750 °C and stress-relieve hard tempers (~230–260 °C) to avoid ammonia-driven stress-corrosion cracking.
What surface finishes work on C74000?
Takes a bright mirror polish and is an excellent base for Ag, Ni or Cr plating; lacquer or clear coat if tarnish-free service in humid or handled applications is required.
C74000 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 |
|---|---|---|
| Cuincluding Ag per ASTM practice | 69 – 73.5 | 71 |
| Niincluding Co | 9 – 11 | 10 |
| Pb | ≤ 0.1 | — |
| Fe | ≤ 0.25 | — |
| Mn | ≤ 0.5 | — |
| Znremainder, nominally ~19 % | balance | — |
C74000-M20 — frequently asked
What is C74000-M20 used for?
C74000-M20 is typically used for hardware fittings, eyeglass frames, musical instruments and decorative trim. In short: most formable nickel silver; excellent plating substrate; hardest common nickel silver.
What is the yield strength of C74000-M20?
C74000-M20 has a typical yield strength of 140 MPa (20.3 ksi) and a tensile strength of 360 MPa (52.2 ksi) — weaker than 74% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C74000-M20 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy and abrasive on tooling (≈20 % of free-cutting brass) — use sharp positive-rake carbide, high speed with light feeds and copious lubricant; consider leaded C79300 if turning volume is high.
Can C74000-M20 be welded?
Yes — weldability is rated good (55/100). Best joined by GTAW/GMAW with Cu-Ni filler or by silver brazing/soldering; resistance welding is fair and oxyacetylene welding risks zinc fume loss — ventilate and avoid overheating.
What surface finishes work on C74000-M20?
Takes a bright mirror polish and is an excellent base for Ag, Ni or Cr plating; lacquer or clear coat if tarnish-free service in humid or handled applications is required.
Can C74000-M20 be formed, bent or molded?
Annealed and quarter-hard stock deep-draws and coins very well; interstage anneal at 600–750 °C and stress-relieve hard tempers (~230–260 °C) to avoid ammonia-driven stress-corrosion cracking.
What is the maximum service temperature of C74000-M20?
C74000-M20 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C74000-H02 and C74000-O60?
H02 is the default condition — default stocked strip/sheet temper — best all-round balance of strength, bendability and polished appearance. O60: pick for deep drawing, spinning and severe bending of decorative parts. Yield strength is 380 MPa in H02 versus 120 MPa in O60.
Sources
- ASTM B122/B122M — Copper-Nickel-Tin, Copper-Nickel-Zinc (Nickel Silver) Plate, Sheet, Strip and Rolled Bar — ASTM International (2021)
- ASTM B151/B151M — Copper-Nickel-Zinc and Copper-Nickel Rod and Bar — ASTM International (2021)
- CDA/UNS C74000 alloy datasheet (copper.org Alloy Database) — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Nickel Silvers) — ASM International (1990)
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.