Copper Alloy C73200-M20
Finish state
UNS C73200
M20 = as hot rolled
Mill-finished hot-worked bar or plate for parts that will be machined all over.
Values for the M20 condition
Other C73200 tempers and conditions
C73200 is listed in 10 conditions; see the grade overview at C73200.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick for deep drawing, spinning, severe bending and stamping of decorative parts. | 125 | 380 | 40 | 70 HB | — |
M20This page As hot rolled | Mill-finished hot-worked bar or plate for parts that will be machined all over. | 165 | 400 | 35 | 75 HB | 11.5 % IACS |
Quarter hard | Pick when moderate bending is still needed but annealed strip is too soft to handle. | 275 | 415 | 25 | 105 HB | 11 % IACS |
Light drawn | Pick for nickel silver tube that must still be bent or expanded after drawing. | 275 | 430 | 22 | 105 HB | 11 % IACS |
H02Default Half hard | Default stocked strip/rod temper: balance of strength, mild formability and a surface that polishes well. | 380 | 470 | 12 | 130 HB | 11 % IACS |
Three-quarter hard | Intermediate temper for flat parts that need extra stiffness with only slight forming. | 420 | 505 | 8 | 145 HB | 10.8 % IACS |
Full hard | Pick for flat springs, stiff trim and parts blanked with minimal bending. | 450 | 540 | 5 | 155 HB | 10.7 % IACS |
Extra hard | Pick for high-stiffness flat stock and light spring contacts; forming is limited to gentle radii. | 510 | 590 | 3 | 175 HB | 10.6 % IACS |
Spring hard | Pick for springy clips and instrument parts needing high elastic limit. | 545 | 635 | 2 | 185 HB | 10.5 % IACS |
Extra spring hard | Highest-strength rolled temper; only for flat springs bent along preferred direction. | 585 | 680 | 2 | 200 HB | 10.5 % IACS |
What is C73200-M20?
C73200-M20 is C73200 supplied in the M20 condition — mill-finished hot-worked bar or plate for parts that will be machined all over. C73200-M20 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 64% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 125 GPa (18.1 Msi). C73200-M20 has a density of 8.73 g/cm³ (0.315 lb/in³), lighter than 53% of copper alloy grades. It melts at 1,060°C (1,940 °F). H02 is the default condition FabDigit quotes; M20 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 90/100, better than 99% of copper alloy grades
- Forms and bends easily — 90/100, better than 89% of copper alloy grades
- Ductile — tolerates forming and impact — 35%, better than 80% of copper alloy grades
Limitations
- Difficult to machine — 22/100, worse than 94% of copper alloy grades
- High embodied carbon — 4.3 kg CO₂/kg, worse than 77% of copper alloy grades
C73200-M20 properties
Typical room-temperature values for C73200-M20; 21 are specific to this condition. Other listed values are C73200 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C73200-M20 has a density of 8.73 g/cm³ (0.315 lb/in³), lighter than 53% of copper alloy grades. It melts at 1,060°C (1,940 °F).
Mechanical15
C73200-M20 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 64% of copper alloy grades. Elongation at break is 35% and the elastic modulus is 125 GPa (18.1 Msi).
Thermal6
C73200-M20 is rated for continuous service to 250°C (482 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), worse than 73% of copper alloy grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
C73200-M20 conducts electricity at 11.5 % IACS, worse than 65% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 64% of copper alloy grades.
Sustainability4
Producing a kilogram of C73200-M20 takes about 62 MJ of energy and emits 4.3 kg of CO₂ — more than 76% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C73200-M20's machinability is poor (22/100, worse than 94% of copper alloy grades); weldability good (58/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C73200-M20
Is C73200 easy to machine?
Gummy, non-free-cutting: use sharp positive-rake carbide, moderate speed, generous soluble-oil coolant and chip breakers; expect ~20 % of AISI 1212 productivity.
Can C73200 be welded?
Best joined by resistance spot/seam, silver brazing or soft soldering; TIG/GTAW is possible with matching or Cu-Ni filler but zinc fume and hot-short cracking demand fume extraction and low heat input.
Can C73200 be formed, bent or molded?
Excellent deep-drawing and stamping in O60/H01; interstage anneal at 600–750 °C and stress-relieve cold-worked parts at ~250–300 °C to avoid ammonia stress-corrosion cracking.
What surface finishes work on C73200?
Buffs to a bright silver-white finish and takes nickel, silver, chrome or gold plating readily; lacquer or clear coat to keep the finish from dulling outdoors.
C73200 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 |
|---|---|---|
| Ninominal nickel level for this high-copper nickel silver; verify against mill certificate | 9 – 11 | 10 |
| Znremainder of the alloying addition | 8 – 11 | 9.5 |
| Mndeoxidiser addition typical of nickel silvers | ≤ 0.5 | 0.2 |
| Feimpurity limit | ≤ 0.25 | — |
| Pbunleaded grade | ≤ 0.05 | — |
| CuCu + Ni + Zn ≥ 99.5 % | balance | — |
C73200-M20 — frequently asked
What is C73200-M20 used for?
C73200-M20 is typically used for decorative hardware, musical instrument parts, costume jewelry and flatware. In short: silver-white without silver; lower-nickel nickel silver; deep-draws and buffs well.
What is the yield strength of C73200-M20?
C73200-M20 has a typical yield strength of 165 MPa (23.9 ksi) and a tensile strength of 400 MPa (58 ksi) — weaker than 64% of copper alloy grades. Strength varies by condition: see the 10 listed tempers.
Is C73200-M20 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 94% of copper alloy grades). Gummy, non-free-cutting: use sharp positive-rake carbide, moderate speed, generous soluble-oil coolant and chip breakers; expect ~20 % of AISI 1212 productivity.
Can C73200-M20 be welded?
Yes — weldability is rated good (58/100). Best joined by resistance spot/seam, silver brazing or soft soldering; TIG/GTAW is possible with matching or Cu-Ni filler but zinc fume and hot-short cracking demand fume extraction and low heat input.
What surface finishes work on C73200-M20?
Buffs to a bright silver-white finish and takes nickel, silver, chrome or gold plating readily; lacquer or clear coat to keep the finish from dulling outdoors.
Can C73200-M20 be formed, bent or molded?
Excellent deep-drawing and stamping in O60/H01; interstage anneal at 600–750 °C and stress-relieve cold-worked parts at ~250–300 °C to avoid ammonia stress-corrosion cracking.
What is the maximum service temperature of C73200-M20?
C73200-M20 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C73200-H02 and C73200-O60?
H02 is the default condition — default stocked strip/rod temper: balance of strength, mild formability and a surface that polishes well. O60: pick for deep drawing, spinning, severe bending and stamping of decorative parts. Yield strength is 380 MPa in H02 versus 125 MPa in O60.
Sources
- ASM Handbook, Vol. 2: Properties and Selection — Nonferrous Alloys (Cu-Ni-Zn nickel silvers) — ASM International (1990)
- Copper Alloy Data — Wrought Nickel Silvers (C73xxx–C79xxx) — Copper Development Association (copper.org) (2023)
- ASTM B122/B122M — Copper-Nickel-Tin, Copper-Nickel-Zinc Plate, Sheet, Strip and Rolled Bar — ASTM International (2022)
- ASTM B151/B151M — Copper-Nickel-Zinc (Nickel Silver) and Copper-Nickel Rod and Bar — ASTM International (2019)
- 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.