Copper Alloy C79800
UNS C79800
C79800 is a leaded, free-machining wrought nickel silver (C70000–C79999 family), a copper-nickel-zinc alloy with a lead phase added for chip breaking.
Reference datasheet — C79800 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
C79800 tempers and conditions
C79800 is supplied in 7 conditions, soft to hard. H02 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum ductility when parts are headed, staked, crimped or heavily formed after machining. | 170 | 400 | 35 | 100 HB | — |
As hot extruded | Mill condition for large-diameter rod and forging stock before drawing or machining. | 200 | 430 | 30 | 110 HB | 7.5 % IACS |
Quarter hard | Compromise temper when parts must be both machined and moderately bent or riveted. | 300 | 470 | 25 | 130 HB | — |
H02Default Half hard | Standard stock condition for screw-machine rod and bar: best balance of chip control, strength and dimensional stability. | 400 | 525 | 15 | 155 HB | — |
Full hard | Choose when finished parts need higher strength, wear resistance and stiffness with little forming. | 480 | 585 | 8 | 175 HB | — |
Extra hard | Heavily drawn wire/flat stock for springy contacts and stamped parts needing maximum hardness. | 525 | 620 | 5 | 11 HRC | 7 % IACS |
Spring hard | Maximum cold-worked strength for small springs and clips; essentially no bending capacity across the grain. | 570 | 660 | 3 | 15 HRC | 7 % IACS |
What is C79800?
C79800 is a leaded, free-machining wrought nickel silver (C70000–C79999 family), a copper-nickel-zinc alloy with a lead phase added for chip breaking. It is specified for high-speed screw-machine production of small precision hardware, offering 400 MPa yield, 525 MPa tensile, 155 HB and a machinability rating near 60% of AISI 1212 in rod and bar form. Formability is limited (score 40) in H04 and harder, fusion welding is not viable because of lead hot cracking, and the lead content restricts use where lead-free material is mandated; unleaded nickel silvers such as C75200 are the alternative there. C79800 has a density of 8.69 g/cm³ (0.314 lb/in³), lighter than 57% of copper alloy grades. It melts at 890°C (1,634 °F). C79800 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 525 MPa (76.1 ksi) — stronger than 80% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 117 GPa (17 Msi).
What is C79800 used for?
- precision fasteners
- instrument parts
- eyeglass frames
- plumbing fittings
Advantages
- Polishes to a fine finish — 85/100, better than 92% of copper alloy grades
- High strength — 400 MPa (58 ksi), better than 80% of copper alloy grades
- Easy to machine — 68/100, better than 77% of copper alloy grades
Limitations
- Difficult to weld — 15/100, worse than 94% of copper alloy grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades
- Low electrical conductivity — 7 % IACS, worse than 86% of copper alloy grades
- High embodied carbon — 4.8 kg CO₂/kg, worse than 84% of copper alloy grades
C79800 properties
Typical room-temperature values for C79800-H02; bars are the position among copper alloy grades.
Physical3
C79800 has a density of 8.69 g/cm³ (0.314 lb/in³), lighter than 57% of copper alloy grades. It melts at 890°C (1,634 °F).
Mechanical12
C79800 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 525 MPa (76.1 ksi) — stronger than 80% of copper alloy grades. Elongation at break is 15% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C79800 is rated for continuous service to 200°C (392 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
C79800 conducts electricity at 7 % IACS, worse than 86% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 86% of copper alloy grades.
Sustainability4
Producing a kilogram of C79800 takes about 72 MJ of energy and emits 4.8 kg of CO₂ — more than 86% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C79800's machinability is good (68/100, better than 77% of copper alloy grades); weldability poor (15/100); formability fair (40/100).
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. C79800 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C79800
Is C79800 easy to machine?
Excellent free-cutting behaviour (≈60% of AISI 1212); use sharp positive-rake carbide or HSS with light soluble-oil mist, high speeds and moderate feeds — chips break short thanks to the lead phase.
Can C79800 be welded?
Not recommended for fusion welding (lead hot-cracks, zinc fumes); joint by soft soldering, low-temperature silver brazing, riveting or press fits, with fume extraction.
Can C79800 be formed, bent or molded?
Hot work 650–800 °C; cold bending is limited in H04 and harder — anneal at 600–700 °C and quench/air-cool for severe forming, and avoid ammonia exposure of stressed parts (SCC).
C79800 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 | 45.5 – 48.5 | 47 |
| NiCo counted as Ni | 9 – 11 | 10 |
| Pbfree-machining addition | 1.5 – 2.5 | 2 |
| Mn | 0.05 – 0.5 | 0.25 |
| Feimpurity limit | ≤ 0.25 | 0.1 |
| Znremainder, ≈40–42% | balance |
What surface finishes work on C79800?
Polishes to a bright silver-white; readily nickel-, chrome-, silver- or gold-plated after cyanide-free cleaning; lacquer or benzotriazole passivation preserves tarnish resistance.
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 C79800 cost?
C79800 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.
C79800 — frequently asked
What is C79800 used for?
C79800 is typically used for precision fasteners, instrument parts, eyeglass frames and plumbing fittings. In short: free-machining nickel silver; screw-machine hardware grade; silver-white platable base.
What is the yield strength of C79800?
C79800 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 525 MPa (76.1 ksi) — stronger than 80% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C79800 easy to machine?
Reasonably — machinability is rated good (68/100, better than 77% of copper alloy grades). Excellent free-cutting behaviour (≈60% of AISI 1212); use sharp positive-rake carbide or HSS with light soluble-oil mist, high speeds and moderate feeds — chips break short thanks to the lead phase.
Can C79800 be welded?
Not readily — weldability is rated poor (15/100). Not recommended for fusion welding (lead hot-cracks, zinc fumes); joint by soft soldering, low-temperature silver brazing, riveting or press fits, with fume extraction.
What surface finishes work on C79800?
Polishes to a bright silver-white; readily nickel-, chrome-, silver- or gold-plated after cyanide-free cleaning; lacquer or benzotriazole passivation preserves tarnish resistance.
Can C79800 be formed, bent or molded?
Hot work 650–800 °C; cold bending is limited in H04 and harder — anneal at 600–700 °C and quench/air-cool for severe forming, and avoid ammonia exposure of stressed parts (SCC).
What is the maximum service temperature of C79800?
C79800 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 C79800-H02 and C79800-O61?
H02 is the default condition — standard stock condition for screw-machine rod and bar: best balance of chip control, strength and dimensional stability. O61: pick for maximum ductility when parts are headed, staked, crimped or heavily formed after machining. Yield strength is 400 MPa in H02 versus 170 MPa in O61.
How much does C79800 cost?
C79800 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 B151/B151M — Copper-Nickel-Zinc (Nickel Silver) and Copper-Nickel Rod and Bar — ASTM International (2019)
- CDA/UNS Alloy Datasheet C79800 (leaded nickel silver) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (copper alloys) — ASM International (2005)
- GB/T 5232 / GB/T 2059 BZn (2020)
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.