Copper Alloy C79800-H02
Supply condition · default condition
UNS C79800
H02 = half hard
Standard stock condition for screw-machine rod and bar: best balance of chip control, strength and dimensional stability.
Values for the H02 condition
Other C79800 tempers and conditions
C79800 is listed in 7 conditions; see the grade overview at C79800.
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 | — |
H02DefaultThis page 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-H02?
C79800-H02 is C79800 supplied in the H02 condition — standard stock condition for screw-machine rod and bar: best balance of chip control, strength and dimensional stability. C79800-H02 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). C79800-H02 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).
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-H02 properties
Typical room-temperature values for C79800-H02; 11 are specific to this condition. Other listed values are C79800 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C79800-H02 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-H02 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-H02 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-H02 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-H02 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-H02'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. Confirm any required mill or lot documentation when quoting.
Working with C79800-H02
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).
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.
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 | — |
C79800-H02 — frequently asked
What is C79800-H02 used for?
C79800-H02 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-H02?
C79800-H02 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-H02 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-H02 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-H02?
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-H02 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-H02?
C79800-H02 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.