Copper Alloy C77400
UNS C77400
C77400 is a mid-nickel wrought nickel silver (Cu-Ni-Zn) supplied mainly as strip in OS035 and OS025 annealed tempers and H01 through H10 cold-rolled tempers.
Reference datasheet — C77400 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the H02 condition
C77400 tempers and conditions
C77400 is supplied in 8 conditions, soft to hard. H02 is the default FabDigit quotes; the values on this page are for it.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed to 0.035 mm grain size | Softest commercial strip temper — pick for deep drawing and severe forming of hollowware/flatware blanks. | 170 | 415 | 40 | 100 HB | — |
Annealed to 0.025 mm grain size | Fine-grain anneal for a smoother formed surface and less orange peel on plated parts. | 195 | 430 | 36 | 108 HB | 11.5 % IACS |
Quarter hard | Light cold work for stamped and moderately drawn plating blanks needing more stiffness than annealed strip. | 340 | 460 | 20 | 125 HB | 11 % IACS |
H02Default Half hard | Most widely stocked strip temper — balances stamping/bending formability with useful strength for flatware and hardware. | 440 | 515 | 10 | 145 HB | — |
Full hard | Choose for flat blanking, wear surfaces and parts requiring high strength with only slight bending. | 550 | 620 | 3 | 175 HB | — |
Extra hard | For flat springy parts, slide-fastener elements and stampings that need high yield with minimal forming. | 620 | 690 | 2 | 11 HRC | 11 % IACS |
Spring hard | Spring temper strip for contacts, clips and flexures where high elastic limit matters more than formability. | 660 | 725 | 2 | 13 HRC | 10.5 % IACS |
Extra spring hard | Maximum cold-rolled strength for flat springs and fastener parts; essentially no bending capability across the grain. | 700 | 760 | 1.5 | 16 HRC | 10.5 % IACS |
What is C77400?
C77400 is a mid-nickel wrought nickel silver (Cu-Ni-Zn) supplied mainly as strip in OS035 and OS025 annealed tempers and H01 through H10 cold-rolled tempers. It is used as a base metal for silver electroplating and for decorative flatware because it polishes bright white and cold forms well (formability score 80); the default condition gives 440 MPa yield, 515 MPa tensile, 10% elongation, 145 HB and 78 HRB. Limits are a maximum service temperature of about 200 °C, machinability near 20% of free-cutting brass, and ammonia stress-corrosion cracking risk in cold-worked parts — use leaded C78200 for turned components. C77400 has a density of 8.7 g/cm³ (0.314 lb/in³), lighter than 56% of copper alloy grades. It melts at 960°C (1,760 °F). C77400 has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 85% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 125 GPa (18.1 Msi).
What is C77400 used for?
- silver-plated flatware blanks
- zippers
- hardware
- decorative items
Advantages
- Polishes to a fine finish — 85/100, better than 92% of copper alloy grades
- High strength — 440 MPa (63.8 ksi), better than 85% of copper alloy grades
- Forms and bends easily — 80/100, better than 83% of copper alloy grades
Limitations
- Difficult to machine — 25/100, worse than 86% of copper alloy grades
- High embodied carbon — 4.6 kg CO₂/kg, worse than 82% of copper alloy grades
- Limited ductility — 10%, worse than 76% of copper alloy grades
- Poor heat conductor — 45 W/m·K (26 BTU/hr·ft·°F), worse than 76% of copper alloy grades
C77400 properties
Typical room-temperature values for C77400-H02; bars are the position among copper alloy grades.
Physical3
C77400 has a density of 8.7 g/cm³ (0.314 lb/in³), lighter than 56% of copper alloy grades. It melts at 960°C (1,760 °F).
Mechanical12
C77400 has a yield strength of 440 MPa (63.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 85% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 125 GPa (18.1 Msi).
Thermal5
C77400 is rated for continuous service to 200°C (392 °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
C77400 conducts electricity at 11 % IACS, worse than 68% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 68% of copper alloy grades.
Sustainability4
Producing a kilogram of C77400 takes about 60 MJ of energy and emits 4.6 kg of CO₂ — more than 69% of copper alloy grades. Typical recycled content is 40%.
Manufacturability6
C77400's machinability is poor (25/100, worse than 86% of copper alloy grades); weldability fair (50/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C77400 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C77400
Is C77400 easy to machine?
Machinability only about 20 % of free-cutting brass — use sharp, high-rake tools, positive feed and good lubrication to avoid gummy, stringy chips.
Can C77400 be welded?
Resistance and brazing/soldering are the preferred joining routes; gas and arc fusion welding risk zinc fume loss and porosity, so keep heat input low and ventilate.
Can C77400 be formed, bent or molded?
Excellent cold formability in annealed and quarter-hard tempers (deep drawing, coining, spinning); interanneal at 600–750 °C and stress-relieve cold-worked parts to avoid ammonia SCC.
C77400 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 |
|---|---|---|
| Cu | 43 – 47 | 45 |
| NiNi + Co | 9 – 11 | 10 |
| Fe | ≤ 0.5 | |
| Mn | ≤ 0.5 | |
| Pb | ≤ 0.05 | |
| Znremainder, nominally ~45 % | balance |
What surface finishes work on C77400?
Takes a bright white polish and is the classic base metal for silver, nickel and chrome electroplating; degrease and lightly acid-activate before plating.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
How much does C77400 cost?
C77400 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C77400 — frequently asked
What is C77400 used for?
C77400 is typically used for silver-plated flatware blanks, zippers, hardware and decorative items. In short: classic silver-plating base metal; strip-form nickel silver; strong yet still drawable.
What is the yield strength of C77400?
C77400 has a typical yield strength of 440 MPa (63.8 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 85% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C77400 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 86% of copper alloy grades). Machinability only about 20 % of free-cutting brass — use sharp, high-rake tools, positive feed and good lubrication to avoid gummy, stringy chips.
Can C77400 be welded?
With care — weldability is rated fair (50/100). Resistance and brazing/soldering are the preferred joining routes; gas and arc fusion welding risk zinc fume loss and porosity, so keep heat input low and ventilate.
What surface finishes work on C77400?
Takes a bright white polish and is the classic base metal for silver, nickel and chrome electroplating; degrease and lightly acid-activate before plating.
Can C77400 be formed, bent or molded?
Excellent cold formability in annealed and quarter-hard tempers (deep drawing, coining, spinning); interanneal at 600–750 °C and stress-relieve cold-worked parts to avoid ammonia SCC.
What is the maximum service temperature of C77400?
C77400 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 C77400-H02 and C77400-OS035?
H02 is the default condition — most widely stocked strip temper — balances stamping/bending formability with useful strength for flatware and hardware. OS035: softest commercial strip temper — pick for deep drawing and severe forming of hollowware/flatware blanks. Yield strength is 440 MPa in H02 versus 170 MPa in OS035.
How much does C77400 cost?
C77400 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B122/B122M — Copper-Nickel-Zinc (Nickel Silver) Plate, Sheet, Strip and Rolled Bar — ASTM (2022)
- ASTM B151/B151M — Copper-Nickel-Zinc and Copper-Nickel Rod and Bar — ASTM (2019)
- CDA Alloy Database — C77400 nickel silver 45-10 — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol.2 — Properties of Nonferrous Alloys (Nickel Silvers) — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.