Copper Alloy C66700-H04
Supply condition
UNS C66700
H04 = full hard
Standard hard temper for flat springs, clips and wear-resistant stampings with only gentle forming.
Values for the H04 condition
Other C66700 tempers and conditions
C66700 is listed in 9 conditions; see the grade overview at C66700.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed to 0.050 mm grain size | Softest commercial temper for deep drawing and severe bending of strip. | 110 | 350 | 60 | 65 HB | — |
Annealed to 0.025 mm grain size | Fine-grain annealed strip: smoother formed surfaces and slightly higher strength than OS050. | 140 | 375 | 52 | 80 HB | — |
Quarter hard | Light cold work for parts needing moderate stiffness with generous bending. | 275 | 420 | 40 | 105 HB | — |
H02Default Half hard | Most-stocked balance of strength and formability for stamped hardware and fasteners. | 380 | 470 | 25 | 120 HB | — |
Three-quarter hard | Higher strength with limited bend capability, for load-carrying stampings. | 430 | 515 | 16 | 140 HB | — |
H04This page Full hard | Standard hard temper for flat springs, clips and wear-resistant stampings with only gentle forming. | 470 | 550 | 10 | 155 HB | — |
Extra hard | For high-stiffness contacts and wear parts where forming is limited to flat blanking. | 540 | 620 | 6 | 175 HB | — |
Spring hard | Spring temper strip/wire for high elastic-limit contacts and washers. | 580 | 660 | 4 | 190 HB | — |
Extra spring hard | Maximum cold-worked strength; brittle to bending, used for flat springs and thin high-load contacts. | 615 | 690 | 3 | 200 HB | — |
What is C66700-H04?
C66700-H04 is C66700 supplied in the H04 condition — standard hard temper for flat springs, clips and wear-resistant stampings with only gentle forming. C66700-H04 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 87% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 110 GPa (16 Msi). C66700-H04 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 915°C (1,679 °F). H02 is the default condition FabDigit quotes; H04 is available on request or by drawing note.
Advantages
- High strength — 470 MPa (68.2 ksi), better than 87% of copper alloy grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 96% of copper alloy grades
- Limited ductility — 10%, worse than 76% of copper alloy grades
C66700-H04 properties
Typical room-temperature values for C66700-H04; 10 are specific to this condition. Other listed values are C66700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C66700-H04 has a density of 8.41 g/cm³ (0.304 lb/in³), lighter than 72% of copper alloy grades. It melts at 915°C (1,679 °F).
Mechanical12
C66700-H04 has a yield strength of 470 MPa (68.2 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 87% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
C66700-H04 is rated for continuous service to 150°C (302 °F). It conducts heat at 84 W/m·K (48.5 BTU/hr·ft·°F), better than 51% of copper alloy grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical3
C66700-H04 conducts electricity at 17 % IACS, better than 50% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C66700-H04 takes about 55 MJ of energy and emits 3.6 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 45%.
Manufacturability8
C66700-H04's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability fair (45/100); formability fair (42/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C66700-H04
Is C66700 easy to machine?
Machinability roughly 30 % of free-cutting brass — gummy chips; use sharp positive-rake carbide, high speed, light feeds and good lubrication.
Can C66700 be welded?
Resistance and GTAW welding are fair; zinc volatilises so use ventilation and low heat input, and prefer brazing or soldering for joints.
Can C66700 be formed, bent or molded?
Excellent deep-draw and bend behaviour in OS tempers; interstage anneal at 425–600 °C, and stress-relieve cold-worked parts near 260 °C to avoid season cracking.
What surface finishes work on C66700?
Not anodisable; bright-dip, mechanically polish, or apply Ni/Cr, tin or clear lacquer — keep away from ammonia-based cleaners.
C66700 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 | 68.5 – 71.5 | 70 |
| Mnsolid-solution strengthener | 0.8 – 1.5 | 1.1 |
| Fe | ≤ 0.1 | — |
| Pb | ≤ 0.07 | — |
| Zn | balance | — |
C66700-H04 — frequently asked
What is C66700-H04 used for?
C66700-H04 is typically used for fasteners, wear-resistant components and structural hardware. In short: manganese-strengthened drawing brass; 25 % elongation strip; stronger than cartridge brass.
What is the yield strength of C66700-H04?
C66700-H04 has a typical yield strength of 470 MPa (68.2 ksi) and a tensile strength of 550 MPa (79.8 ksi) — stronger than 87% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C66700-H04 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% of copper alloy grades). Machinability roughly 30 % of free-cutting brass — gummy chips; use sharp positive-rake carbide, high speed, light feeds and good lubrication.
Can C66700-H04 be welded?
With care — weldability is rated fair (45/100). Resistance and GTAW welding are fair; zinc volatilises so use ventilation and low heat input, and prefer brazing or soldering for joints.
What surface finishes work on C66700-H04?
Not anodisable; bright-dip, mechanically polish, or apply Ni/Cr, tin or clear lacquer — keep away from ammonia-based cleaners.
Can C66700-H04 be formed, bent or molded?
Excellent deep-draw and bend behaviour in OS tempers; interstage anneal at 425–600 °C, and stress-relieve cold-worked parts near 260 °C to avoid season cracking.
What is the maximum service temperature of C66700-H04?
C66700-H04 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C66700-H02 and C66700-OS050?
H02 is the default condition — most-stocked balance of strength and formability for stamped hardware and fasteners. OS050: softest commercial temper for deep drawing and severe bending of strip. Yield strength is 380 MPa in H02 versus 110 MPa in OS050.
Sources
- CDA Alloy Data: C66700 Manganese Brass — Copper Development Association (copper.org) (2024)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASTM B36/B36M — Brass Plate, Sheet, Strip and Rolled Bar — ASTM (2018)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM (2019)
- ASM Handbook Vol.13B — Corrosion: Materials (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.