Copper Alloy C12500-H08
Supply condition
UNS C12500
H08 = spring hard
Spring-rolled strip for gaskets, shim and low-stress spring contacts.
Values for the H08 condition
Other C12500 tempers and conditions
C12500 is listed in 12 conditions; see the grade overview at C12500.
Compare all 12 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed to 0.050 mm grain size | Soft, coarse-grain anneal for deep drawing and severe forming. | 69 | 220 | 45 | 42 HB | 100 % IACS |
As hot extruded | Standard as-extruded condition for bus bar, forging stock and machined fittings. | 70 | 215 | 50 | 42 HB | 99 % IACS |
Annealed to 0.025 mm grain size | Fine-grain soft temper — better surface finish after forming than OS050. | 76 | 235 | 45 | 45 HB | 100 % IACS |
As hot rolled | Cheapest mill condition for heavy plate and roofing sheet where temper control is not critical. | 85 | 235 | 45 | 48 HB | 99 % IACS |
1/8 hard | Slight stiffening while keeping near-soft formability; good for roll-formed profiles. | 170 | 250 | 30 | 62 HB | 98 % IACS |
Quarter hard | Balanced temper for bent brackets, gutters and moderately formed parts. | 205 | 265 | 25 | 70 HB | 98 % IACS |
Half hard | Most common cold-worked sheet/strip temper — usable strength with some bendability. | 250 | 290 | 14 | 82 HB | 97 % IACS |
Three-quarter hard | Stiffer flat product for gaskets, washers and lightly formed hardware. | 275 | 315 | 10 | 89 HB | 97 % IACS |
H04Default Full hard | Default stocked temper for bar, bus bar and hard sheet where strength and straightness matter. | 310 | 345 | 6 | 95 HB | 97 % IACS |
Extra hard | Higher cold reduction for flat springs, contacts and stiff strip; very limited bending. | 340 | 365 | 4 | 100 HB | 97 % IACS |
H08This page Spring hard | Spring-rolled strip for gaskets, shim and low-stress spring contacts. | 350 | 380 | 4 | 105 HB | 96 % IACS |
Extra spring hard | Maximum cold-worked strength available in thin strip/wire; essentially no formability. | 365 | 395 | 3 | 110 HB | 96 % IACS |
What is C12500-H08?
C12500-H08 is C12500 supplied in the H08 condition — spring-rolled strip for gaskets, shim and low-stress spring contacts. C12500-H08 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 380 MPa (55.1 ksi) — stronger than 74% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi). C12500-H08 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,065°C (1,949 °F). H04 is the default condition FabDigit quotes; H08 is available on request or by drawing note.
Advantages
- Conducts heat well — 382 W/m·K (220.7 BTU/hr·ft·°F), better than 91% of copper alloy grades
- High electrical conductivity — 96 % IACS, better than 91% of copper alloy grades
- Low embodied carbon — 3.3 kg CO₂/kg, better than 90% of copper alloy grades
Limitations
- Limited service temperature — 130°C (266 °F), worse than 100% of copper alloy grades
- Limited ductility — 4%, worse than 96% of copper alloy grades
- Difficult to machine — 23/100, worse than 91% of copper alloy grades
C12500-H08 properties
Typical room-temperature values for C12500-H08; 13 are specific to this condition. Other listed values are C12500 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C12500-H08 has a density of 8.94 g/cm³ (0.323 lb/in³), heavier than 90% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Mechanical12
C12500-H08 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 380 MPa (55.1 ksi) — stronger than 74% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C12500-H08 is rated for continuous service to 130°C (266 °F). It conducts heat at 382 W/m·K (220.7 BTU/hr·ft·°F), better than 91% of copper alloy grades. Thermal expansion is 17.7 µm/m·K (9.83 µin/in·°F).
Electrical3
C12500-H08 conducts electricity at 96 % IACS, better than 91% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 69% of copper alloy grades.
Sustainability4
Producing a kilogram of C12500-H08 takes about 53 MJ of energy and emits 3.3 kg of CO₂ — less than 85% of copper alloy grades. Typical recycled content is 45%.
Manufacturability8
C12500-H08's machinability is poor (23/100, worse than 91% of copper alloy grades); weldability fair (35/100); formability poor (20/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C12500-H08
Is C12500 easy to machine?
Gummy and low-rated (~20 % of free-cutting brass): use sharp positive-rake tools, high speed, generous coolant, or switch to C14500/C36000 for screw-machine work.
Can C12500 be welded?
Oxygen-bearing copper — prefer brazing/soldering or friction/resistance joining; GTAW/GMAW is possible with deoxidised filler (ERCu) but risks hydrogen embrittlement and porosity, and heating above 400 °C in reducing atmospheres must be avoided.
Can C12500 be formed, bent or molded?
Excellent cold formability in OS tempers (deep draw, spin, roll-form); interanneal at 400–600 °C when total cold reduction exceeds ~50 %.
What surface finishes work on C12500?
Not anodisable; takes bright polishing, chemical patina/oxidation blackening, tin, nickel or silver plating, and clear lacquer to slow natural tarnish.
C12500 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.
| Element | Spec limit (wt %) |
|---|---|
| Ooxygen present as Cu2O (tough pitch); typically 0.02–0.05 %, not a specified limit | ≈ 0.04 |
| Sb | ≤ 0.01 |
| As | ≤ 0.01 |
| Bi | ≤ 0 |
| Fe | ≤ 0.01 |
| Pb | ≤ 0.01 |
| Ni | ≤ 0.05 |
| Se | ≤ 0 |
| S | ≤ 0 |
| Sn | ≤ 0.05 |
| Te | ≤ 0.03 |
| Zn | ≤ 0.05 |
| CuCu + Ag, fire-refined tough pitch | ≥ 99.88 (balance) |
C12500-H08 — frequently asked
What is C12500-H08 used for?
C12500-H08 is typically used for builder's hardware, general sheet and wire products and roofing. In short: low-cost general-purpose copper; 97 % IACS without ETP purity; excellent cold formability.
What is the yield strength of C12500-H08?
C12500-H08 has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 380 MPa (55.1 ksi) — stronger than 74% of copper alloy grades. Strength varies by condition: see the 12 listed tempers.
Is C12500-H08 easy to machine?
Not especially — machinability is rated poor (23/100, worse than 91% of copper alloy grades). Gummy and low-rated (~20 % of free-cutting brass): use sharp positive-rake tools, high speed, generous coolant, or switch to C14500/C36000 for screw-machine work.
Can C12500-H08 be welded?
With care — weldability is rated fair (35/100). Oxygen-bearing copper — prefer brazing/soldering or friction/resistance joining; GTAW/GMAW is possible with deoxidised filler (ERCu) but risks hydrogen embrittlement and porosity, and heating above 400 °C in reducing atmospheres must be avoided.
What surface finishes work on C12500-H08?
Not anodisable; takes bright polishing, chemical patina/oxidation blackening, tin, nickel or silver plating, and clear lacquer to slow natural tarnish.
Can C12500-H08 be formed, bent or molded?
Excellent cold formability in OS tempers (deep draw, spin, roll-form); interanneal at 400–600 °C when total cold reduction exceeds ~50 %.
What is the maximum service temperature of C12500-H08?
C12500-H08 is rated for continuous use to about 130°C (266 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C12500-H04 and C12500-OS050?
H04 is the default condition — default stocked temper for bar, bus bar and hard sheet where strength and straightness matter. OS050: soft, coarse-grain anneal for deep drawing and severe forming. Yield strength is 310 MPa in H04 versus 69 MPa in OS050.
Sources
- ASTM B5 — Electrolytic Tough Pitch / Fire-Refined Copper Refinery Shapes — ASTM International (2021)
- ASTM B152/B152M — Copper Sheet, Strip, Plate and Rolled Bar — ASTM International (2019)
- CDA Alloy Datasheet C12500 (Fire-Refined Tough Pitch Copper) — 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.