Copper Alloy C43400-H08
Supply condition
UNS C43400
H08 = spring hard
Spring temper strip for resilient sealing fingers and contact springs; forming limited to large radii, stress-relieve after forming.
Values for the H08 condition
Other C43400 tempers and conditions
C43400 is listed in 9 conditions; see the grade overview at C43400.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed to 0.035 mm grain size | Softest commercial strip temper — pick for deep drawing, tight bends and hose convolution forming. | 124 | 345 | 48 | 50 HRB | 27 % IACS |
Annealed to 0.015 mm grain size | Fine-grain anneal — choose when a smooth orange-peel-free surface after forming matters more than maximum ductility. | 140 | 359 | 45 | 55 HRB | 27 % IACS |
Quarter hard | Light cold work — a compromise temper for parts that are formed then need modest stiffness. | 310 | 400 | 25 | 70 HRB | 26 % IACS |
H02Default Half hard | The default stocked strip temper — balanced strength and bendability for weatherstrip, hose strip and formed hardware. | 380 | 448 | 14 | 78 HRB | 26 % IACS |
Three-quarter hard | Higher spring-back and strength for lightly formed clips and retainers. | 427 | 496 | 9 | 83 HRB | 26 % IACS |
Full hard | Standard hard strip for flexible hose interlock and weatherstrip that is only slightly bent after slitting. | 475 | 545 | 5 | 87 HRB | 26 % IACS |
Extra hard | For flat springs and contacts where only very generous bend radii are used. | 525 | 600 | 4 | 90 HRB | 25 % IACS |
H08This page Spring hard | Spring temper strip for resilient sealing fingers and contact springs; forming limited to large radii, stress-relieve after forming. | 565 | 634 | 3 | 92 HRB | 25 % IACS |
Extra spring hard | Maximum strength/spring rate available in this alloy; essentially flat-form use only. | 586 | 655 | 2 | 93 HRB | 25 % IACS |
What is C43400-H08?
C43400-H08 is C43400 supplied in the H08 condition — spring temper strip for resilient sealing fingers and contact springs; forming limited to large radii, stress-relieve after forming. C43400-H08 has a yield strength of 565 MPa (81.9 ksi) and a tensile strength of 634 MPa (92 ksi) — stronger than 93% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 110 GPa (16 Msi). C43400-H08 has a density of 8.75 g/cm³ (0.316 lb/in³), lighter than 51% of copper alloy grades. It melts at 1,000°C (1,832 °F). H02 is the default condition FabDigit quotes; H08 is available on request or by drawing note.
Advantages
- High strength — 565 MPa (81.9 ksi), better than 93% of copper alloy grades
Limitations
- Limited service temperature — 140°C (284 °F), worse than 100% of copper alloy grades
- Limited ductility — 3%, worse than 97% of copper alloy grades
C43400-H08 properties
Typical room-temperature values for C43400-H08; 11 are specific to this condition. Other listed values are C43400 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C43400-H08 has a density of 8.75 g/cm³ (0.316 lb/in³), lighter than 51% of copper alloy grades. It melts at 1,000°C (1,832 °F).
Mechanical11
C43400-H08 has a yield strength of 565 MPa (81.9 ksi) and a tensile strength of 634 MPa (92 ksi) — stronger than 93% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 110 GPa (16 Msi).
Thermal6
C43400-H08 is rated for continuous service to 140°C (284 °F). It conducts heat at 121 W/m·K (69.9 BTU/hr·ft·°F), better than 68% of copper alloy grades. Thermal expansion is 19.8 µm/m·K (11 µin/in·°F).
Electrical3
C43400-H08 conducts electricity at 25 % IACS, better than 59% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C43400-H08 takes about 62 MJ of energy and emits 4 kg of CO₂ — more than 76% of copper alloy grades. Typical recycled content is 45%.
Manufacturability7
C43400-H08's machinability is poor (32/100, worse than 57% of copper alloy grades); weldability good (55/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C43400-H08
Is C43400 easy to machine?
Machinability ≈30 % of C36000 — gummy, long chips; use sharp positive-rake tools, high speed and good lubrication; not a screw-machine alloy.
Can C43400 be welded?
Excellent soldering and brazing; resistance and gas-shielded arc welding are fair — zinc fume and porosity are the main issues, so mechanical joints or brazing are preferred.
Can C43400 be formed, bent or molded?
Excellent cold formability in OS tempers (deep draw, roll form, convolute); in H04 and above restrict bends to generous radii transverse to rolling direction.
What surface finishes work on C43400?
Bright-dips, buffs and plates (Ni, Sn, Cr) readily; not anodizable — protect with lacquer or clear coat to prevent tarnish, and stress-relieve hard tempers (≈200–260 °C) to avoid season cracking.
C43400 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 |
|---|---|---|
| CuCu + named elements ≥ 99.6 % | 84 – 87 | 85.5 |
| Snimproves dezincification resistance | 0.4 – 1 | 0.7 |
| Pbimpurity max | ≤ 0.05 | — |
| Feimpurity max | ≤ 0.05 | — |
| Znremainder, ≈13–15 % | balance | — |
C43400-H08 — frequently asked
What is C43400-H08 used for?
C43400-H08 is typically used for flexible hose, weatherstripping and hardware components. In short: formable tin-brass strip; flexible hose and weatherstrip grade; 150 °C service limit.
What is the yield strength of C43400-H08?
C43400-H08 has a typical yield strength of 565 MPa (81.9 ksi) and a tensile strength of 634 MPa (92 ksi) — stronger than 93% of copper alloy grades. Strength varies by condition: see the 9 listed tempers.
Is C43400-H08 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 57% of copper alloy grades). Machinability ≈30 % of C36000 — gummy, long chips; use sharp positive-rake tools, high speed and good lubrication; not a screw-machine alloy.
Can C43400-H08 be welded?
Yes — weldability is rated good (55/100). Excellent soldering and brazing; resistance and gas-shielded arc welding are fair — zinc fume and porosity are the main issues, so mechanical joints or brazing are preferred.
What surface finishes work on C43400-H08?
Bright-dips, buffs and plates (Ni, Sn, Cr) readily; not anodizable — protect with lacquer or clear coat to prevent tarnish, and stress-relieve hard tempers (≈200–260 °C) to avoid season cracking.
Can C43400-H08 be formed, bent or molded?
Excellent cold formability in OS tempers (deep draw, roll form, convolute); in H04 and above restrict bends to generous radii transverse to rolling direction.
What is the maximum service temperature of C43400-H08?
C43400-H08 is rated for continuous use to about 140°C (284 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C43400-H02 and C43400-OS035?
H02 is the default condition — the default stocked strip temper — balanced strength and bendability for weatherstrip, hose strip and formed hardware. OS035: softest commercial strip temper — pick for deep drawing, tight bends and hose convolution forming. Yield strength is 380 MPa in H02 versus 124 MPa in OS035.
Sources
- CDA Alloy Datasheet C43400 (tin brass) — Copper Development Association (2023)
- ASTM B591 — Copper-Zinc-Tin Alloy Plate, Sheet, Strip and Rolled Bar — ASTM International (2022)
- ASTM B601 — Temper Designations for Copper and Copper Alloys — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — 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.