Copper Alloy C66100-H04
Supply condition · default condition
UNS C66100 · ASTM B98
H04 = full hard
Most common off-the-shelf condition for rod and wire: full-hard cold work gives 380 MPa yield and good chip breaking for fasteners, valve stems and bushings, but only light bending.
Values for the H04 condition
Other C66100 tempers and conditions
C66100 is listed in 5 conditions; see the grade overview at C66100.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick when maximum ductility is needed for deep drawing, riveting, bending or later cold forming; the soft annealed temper gives 45% elongation at only 125 MPa yield. | 125 | 310 | 45 | 65 HB | 12 % IACS |
Quarter hard | Use when a large bending reserve must be kept while strength and surface cutting improve slightly; quarter-hard cold work lifts yield to 205 MPa with 30% elongation still available. | 205 | 380 | 30 | 90 HB | 12 % IACS |
Half hard | General-purpose compromise between strength and formability: half-hard cold work gives 275 MPa yield at 20% elongation, suiting parts with moderate bends plus heavy turning. | 275 | 450 | 20 | 125 HB | 12 % IACS |
H04DefaultThis page Full hard | Most common off-the-shelf condition for rod and wire: full-hard cold work gives 380 MPa yield and good chip breaking for fasteners, valve stems and bushings, but only light bending. | 380 | 515 | 12 | 150 HB | 12 % IACS |
Extra hard | Choose for spring elements, pins and fine wire that need the highest strength, stiffness and wear resistance with no further forming; heavy cold work leaves just 8% elongation. | 480 | 585 | 8 | 175 HB | 12 % IACS |
What is C66100-H04?
C66100-H04 is C66100 supplied in the H04 condition — most common off-the-shelf condition for rod and wire: full-hard cold work gives 380 MPa yield and good chip breaking for fasteners, valve stems and bushings, but only light bending. C66100-H04 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 77% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 117 GPa (17 Msi). C66100-H04 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 971°C (1,780 °F).
Advantages
- High strength — 380 MPa (55.1 ksi), better than 77% of copper alloy grades
C66100-H04 properties
Typical room-temperature values for C66100-H04; 13 are specific to this condition. Other listed values are C66100 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C66100-H04 has a density of 8.53 g/cm³ (0.308 lb/in³), lighter than 62% of copper alloy grades. It melts at 971°C (1,780 °F).
Mechanical11
C66100-H04 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 77% of copper alloy grades. Elongation at break is 12% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C66100-H04 is rated for continuous service to 200°C (392 °F). It conducts heat at 57 W/m·K (32.9 BTU/hr·ft·°F), worse than 64% of copper alloy grades. Thermal expansion is 18.4 µm/m·K (10.2 µin/in·°F).
Electrical3
C66100-H04 conducts electricity at 12 % IACS, worse than 62% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (70/100), better than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C66100-H04 takes about 60 MJ of energy and emits 3.6 kg of CO₂ — more than 69% of copper alloy grades. Typical recycled content is 40%.
Manufacturability8
C66100-H04's machinability is good (55/100, better than 71% of copper alloy grades); weldability poor (30/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C66100-H04
Is C66100 easy to machine?
Lead produces short, broken chips; use sharp positive-rake carbide, high speed with moderate feed and flood emulsion coolant. Machinability is about half that of free-cutting brass, so run larger clearance angles than on brass to prevent smearing.
Can C66100 be welded?
The lead content causes hot cracking in the weld metal and HAZ, so fusion welding is generally not recommended. If unavoidable, use low-heat-input GTAW with ERCuSi-A filler on pre-cleaned surfaces; brazing, soldering or mechanical joining is preferred.
Can C66100 be formed, bent or molded?
O60 and H01 tempers cold bend, rivet and knurl well. In H04/H06 keep bend radii at 2t or greater and allow for work hardening; hot work at about 700–850 °C and anneal at 480–650 °C with water or air cooling.
What surface finishes work on C66100?
Polishes to a high lustre and can be chemically coloured bronze or black and lacquered; nickel, tin and chrome plating adhere well. Anodizing does not apply, and leaded surfaces must be assessed against lead-free regulations for the intended use.
C66100 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 |
|---|---|---|
| Simain solid-solution strengthening element | 1.5 – 2.2 | 1.8 |
| Pbfree lead particles improve machinability | 0.2 – 0.8 | 0.5 |
| Zn | ≤ 1.5 | — |
| Fe | ≤ 0.25 | — |
| Mn | ≤ 0.7 | — |
| Cubalance, includes silver | ≥ 94 (balance) | — |
C66100-H04 — frequently asked
What is C66100-H04 used for?
C66100-H04 is typically used for gears, bearings and machined fittings. In short: best-machining silicon bronze; leaded free-cutting bronze; screw-machine bronze grade.
What is the yield strength of C66100-H04?
C66100-H04 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 515 MPa (74.7 ksi) — stronger than 77% of copper alloy grades. Strength varies by condition: see the 5 listed tempers.
Is C66100-H04 easy to machine?
Reasonably — machinability is rated good (55/100, better than 71% of copper alloy grades). Lead produces short, broken chips; use sharp positive-rake carbide, high speed with moderate feed and flood emulsion coolant. Machinability is about half that of free-cutting brass, so run larger clearance angles than on brass to prevent smearing.
Can C66100-H04 be welded?
Not readily — weldability is rated poor (30/100). The lead content causes hot cracking in the weld metal and HAZ, so fusion welding is generally not recommended. If unavoidable, use low-heat-input GTAW with ERCuSi-A filler on pre-cleaned surfaces; brazing, soldering or mechanical joining is preferred.
What surface finishes work on C66100-H04?
Polishes to a high lustre and can be chemically coloured bronze or black and lacquered; nickel, tin and chrome plating adhere well. Anodizing does not apply, and leaded surfaces must be assessed against lead-free regulations for the intended use.
Can C66100-H04 be formed, bent or molded?
O60 and H01 tempers cold bend, rivet and knurl well. In H04/H06 keep bend radii at 2t or greater and allow for work hardening; hot work at about 700–850 °C and anneal at 480–650 °C with water or air cooling.
What is the maximum service temperature of C66100-H04?
C66100-H04 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 C66100-H04 and C66100-O60?
H04 is the default condition — most common off-the-shelf condition for rod and wire: full-hard cold work gives 380 MPa yield and good chip breaking for fasteners, valve stems and bushings, but only light bending. O60: pick when maximum ductility is needed for deep drawing, riveting, bending or later cold forming; the soft annealed temper gives 45% elongation at only 125 MPa yield. Yield strength is 380 MPa in H04 versus 125 MPa in O60.
Sources
- ASTM B99/B99M — Copper-Silicon Alloy Wire and Rod — ASTM International (2020)
- CDA/UNS C66100 alloy datasheet (copper.org) — Copper Development Association (2024)
- ASM Handbook Vol.2 — Properties of Nonferrous Alloys (Silicon Bronzes) — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion of Copper and Copper Alloys — ASM International (2005)
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.