Copper Alloy C74400-H03
Supply condition
UNS C74400
H03 = three-quarter hard
Intermediate temper for flat stampings needing higher yield than half hard.
Values for the H03 condition
Other C74400 tempers and conditions
C74400 is listed in 10 conditions; see the grade overview at C74400.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed to 0.050 mm grain size | Softest strip temper for deep drawing and severe forming. | 125 | 365 | 45 | 68 HB | 11 % IACS |
Annealed to 0.035 mm grain size | General-purpose annealed strip balancing drawability and surface finish. | 140 | 385 | 40 | 76 HB | 11 % IACS |
Annealed to 0.015 mm grain size | Fine-grain anneal for smooth 'orange-peel-free' surfaces on shallow-formed decorative parts. | 165 | 405 | 35 | 86 HB | 10.5 % IACS |
Quarter hard | Light temper when moderate bending is still required after rolling. | 340 | 450 | 20 | 107 HB | 10 % IACS |
H02Default Half hard | The default stocked strip/rod temper — good springback control with useful residual formability. | 440 | 515 | 12 | 138 HB | 9.8 % IACS |
H03This page Three-quarter hard | Intermediate temper for flat stampings needing higher yield than half hard. | 500 | 565 | 8 | 155 HB | 9.7 % IACS |
Full hard | Hard temper for flat springs, contacts and parts needing stiffness with only gentle bends. | 545 | 620 | 4 | 170 HB | 9.6 % IACS |
Extra hard | Extra-hard strip for high-stiffness clips and flat spring blanks with minimal forming. | 590 | 675 | 3 | 180 HB | 9.5 % IACS |
Spring hard | Spring temper strip/wire for resilient contacts and springs. | 630 | 725 | 2 | 13 HRC | 9.5 % IACS |
Extra spring hard | Maximum cold-worked strength for thin spring stock; essentially no forming capability. | 665 | 760 | 2 | 15 HRC | 9.4 % IACS |
What is C74400-H03?
C74400-H03 is C74400 supplied in the H03 condition — intermediate temper for flat stampings needing higher yield than half hard. C74400-H03 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 565 MPa (81.9 ksi) — stronger than 89% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 124 GPa (18 Msi). C74400-H03 has a density of 8.7 g/cm³ (0.314 lb/in³), lighter than 56% of copper alloy grades. It melts at 1,020°C (1,868 °F). H02 is the default condition FabDigit quotes; H03 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 90/100, better than 99% of copper alloy grades
- High strength — 500 MPa (72.5 ksi), better than 89% of copper alloy grades
Limitations
- Limited ductility — 8%, worse than 83% of copper alloy grades
- High embodied carbon — 4.5 kg CO₂/kg, worse than 79% of copper alloy grades
- Poor heat conductor — 45 W/m·K (26 BTU/hr·ft·°F), worse than 76% of copper alloy grades
- Low electrical conductivity — 9.7 % IACS, worse than 76% of copper alloy grades
C74400-H03 properties
Typical room-temperature values for C74400-H03; 18 are specific to this condition. Other listed values are C74400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C74400-H03 has a density of 8.7 g/cm³ (0.314 lb/in³), lighter than 56% of copper alloy grades. It melts at 1,020°C (1,868 °F).
Mechanical12
C74400-H03 has a yield strength of 500 MPa (72.5 ksi) and a tensile strength of 565 MPa (81.9 ksi) — stronger than 89% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 124 GPa (18 Msi).
Thermal6
C74400-H03 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
C74400-H03 conducts electricity at 9.7 % IACS, worse than 76% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (61/100), worse than 64% of copper alloy grades.
Sustainability4
Producing a kilogram of C74400-H03 takes about 62 MJ of energy and emits 4.5 kg of CO₂ — more than 76% of copper alloy grades. Typical recycled content is 35%.
Manufacturability7
C74400-H03's machinability is poor (27/100, worse than 81% of copper alloy grades); weldability fair (50/100); formability good (58/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C74400-H03
Is C74400 easy to machine?
Rating ~20 % of free-cutting brass — gummy, long chips; use sharp positive-rake tools, moderate speed and generous coolant, or specify a leaded nickel silver if heavy machining is needed.
Can C74400 be welded?
Best joined by silver brazing or soft soldering; resistance and GTAW welding are possible with care but zinc fuming and hot cracking must be controlled — no cast-alloy fusion practice.
Can C74400 be formed, bent or molded?
Excellent cold formability in annealed tempers (deep draw, roll form, coin); interstage anneal at 600–750 °C and stress-relieve cold-worked parts near 260 °C to avoid ammonia-induced SCC.
What surface finishes work on C74400?
Buffs to a bright silver-white finish and takes nickel, chrome, silver or gold plating readily; commonly lacquered or chemically blackened for decorative hardware.
C74400 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 |
|---|---|---|
| Cusilver-white nickel silver base | 63 – 66.5 | 65 |
| NiNi + Co | 7 – 9 | 8 |
| Pb | ≤ 0.1 | — |
| Fe | ≤ 0.25 | — |
| Mn | ≤ 0.5 | — |
| Znremainder, ~27 % | balance | — |
C74400-H03 — frequently asked
What is C74400-H03 used for?
C74400-H03 is typically used for costume jewelry, hardware trim, nameplates and decorative fittings. In short: low-cost nickel silver; bright silvery stamping strip; cheaper than 65-10.
What is the yield strength of C74400-H03?
C74400-H03 has a typical yield strength of 500 MPa (72.5 ksi) and a tensile strength of 565 MPa (81.9 ksi) — stronger than 89% of copper alloy grades. Strength varies by condition: see the 10 listed tempers.
Is C74400-H03 easy to machine?
Not especially — machinability is rated poor (27/100, worse than 81% of copper alloy grades). Rating ~20 % of free-cutting brass — gummy, long chips; use sharp positive-rake tools, moderate speed and generous coolant, or specify a leaded nickel silver if heavy machining is needed.
Can C74400-H03 be welded?
With care — weldability is rated fair (50/100). Best joined by silver brazing or soft soldering; resistance and GTAW welding are possible with care but zinc fuming and hot cracking must be controlled — no cast-alloy fusion practice.
What surface finishes work on C74400-H03?
Buffs to a bright silver-white finish and takes nickel, chrome, silver or gold plating readily; commonly lacquered or chemically blackened for decorative hardware.
Can C74400-H03 be formed, bent or molded?
Excellent cold formability in annealed tempers (deep draw, roll form, coin); interstage anneal at 600–750 °C and stress-relieve cold-worked parts near 260 °C to avoid ammonia-induced SCC.
What is the maximum service temperature of C74400-H03?
C74400-H03 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 C74400-H02 and C74400-OS050?
H02 is the default condition — the default stocked strip/rod temper — good springback control with useful residual formability. OS050: softest strip temper for deep drawing and severe forming. Yield strength is 440 MPa in H02 versus 125 MPa in OS050.
Sources
- ASTM B122/B122M — Copper-Nickel-Zinc (Nickel Silver) Plate, Sheet, Strip and Rolled Bar — ASTM International (2022)
- ASTM B151/B151M — Copper-Nickel-Zinc Alloy Rod and Bar — ASTM International (2021)
- CDA Standard Designation and Alloy Data (C74000 series nickel silvers) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — 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.