Copper Alloy C11300-H08
Supply condition
UNS C11300 · ASTM B48 · EN CW011A, CR013A
H08 = spring hard
Spring temper strip for conductive leaf springs and contacts that must not soften during reflow soldering.
Values for the H08 condition
Other C11300 tempers and conditions
C11300 is listed in 13 conditions; see the grade overview at C11300.
Compare all 13 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled and annealed | Soft heavy plate/bar for deep forming, bending of busbars and welded fabrications. | 62 | 220 | 48 | 42 HB | 101 % IACS |
Soft annealed | Standard fully annealed condition for maximum ductility, drawing, spinning and gasket/roofing use. | 76 | 235 | 45 | 45 HB | 101 % IACS |
As hot rolled | Mill product taken straight off the hot mill — cheapest heavy plate/bar for busbar and grounding parts where temper is not critical. | 90 | 235 | 42 | 50 HB | 100 % IACS |
1/8 hard | Lightly stiffened strip that still bends freely — good for formed terminals needing slight springback control. | 170 | 250 | 32 | 60 HB | 100 % IACS |
Light drawn | Lightly drawn tube/rod that still bends and flares, common for conductive tubing and machined blanks. | 205 | 260 | 25 | 68 HB | 99 % IACS |
Quarter hard | Best compromise of formability and strength for stamped, bent contacts and clips. | 215 | 275 | 25 | 70 HB | 99 % IACS |
Half hard | General-purpose semi-rigid strip/bar: busbar links, commutator risers, moderate 90° bends across grain. | 255 | 300 | 14 | 85 HB | 99 % IACS |
Three-quarter hard | Higher stiffness with limited bending — used for flat springs and stiff conductor strip. | 285 | 320 | 10 | 93 HB | 98 % IACS |
H04Default Full hard | The workhorse stocked temper: full-hard strip/bar/rod that keeps its hardness through soldering thanks to the silver addition. | 310 | 345 | 6 | 100 HB | 98 % IACS |
Extra hard | Extra-hard strip for stiff, flat-formed parts and blanking where minimal bending is required. | 330 | 365 | 5 | 105 HB | 97.5 % IACS |
H08This page Spring hard | Spring temper strip for conductive leaf springs and contacts that must not soften during reflow soldering. | 345 | 380 | 4 | 110 HB | 97 % IACS |
Hard drawn | Hard-drawn wire/rod for magnet-wire, commutator bars and windings that must resist softening during soldering or short-term overload. | 350 | 400 | 3 | 105 HB | 97.5 % IACS |
Extra spring hard | Maximum cold-worked strength available in the grade; for thin flat springs and shims with essentially no forming. | 360 | 395 | 3.5 | 115 HB | 97 % IACS |
What is C11300-H08?
C11300-H08 is C11300 supplied in the H08 condition — spring temper strip for conductive leaf springs and contacts that must not soften during reflow soldering. C11300-H08 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 380 MPa (55.1 ksi) — stronger than 73% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi). C11300-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 — 386 W/m·K (223 BTU/hr·ft·°F), better than 93% of copper alloy grades
- High electrical conductivity — 97 % IACS, better than 92% of copper alloy grades
- Polishes to a fine finish — 85/100, better than 92% of copper alloy grades
Limitations
- Limited ductility — 4%, worse than 96% of copper alloy grades
C11300-H08 properties
Typical room-temperature values for C11300-H08; 14 are specific to this condition. Other listed values are C11300 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C11300-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).
Mechanical13
C11300-H08 has a yield strength of 345 MPa (50 ksi) and a tensile strength of 380 MPa (55.1 ksi) — stronger than 73% of copper alloy grades. Elongation at break is 4% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
C11300-H08 is rated for continuous service to 190°C (374 °F). It conducts heat at 386 W/m·K (223 BTU/hr·ft·°F), better than 93% of copper alloy grades. Thermal expansion is 17 µm/m·K (9.44 µin/in·°F).
Electrical3
C11300-H08 conducts electricity at 97 % IACS, better than 92% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C11300-H08 takes about 57 MJ of energy and emits 3.6 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 35%.
Manufacturability8
C11300-H08's machinability is poor (34/100, worse than 53% of copper alloy grades); weldability fair (35/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C11300-H08
Is C11300 easy to machine?
Gummy and stringy like ETP copper (≈20 % of free-cutting brass) — use sharp positive-rake tools, high speed, generous coolant, and avoid dwelling; consider C14500/C36000 if heavy machining dominates.
Can C11300 be welded?
Resistance and brazing/soldering are excellent; fusion welding is compromised by the 0.02–0.05 % oxygen (porosity, hydrogen embrittlement) so prefer deoxidised C12200 filler, EB/laser or friction welding for critical joints.
Can C11300 be formed, bent or molded?
Annealed and 1/8–1/4 hard tempers deep draw, coin and bend to very tight radii; hard tempers need generous bend radii (≥1–2 t across grain) and interstage annealing at 400–600 °C.
What surface finishes work on C11300?
Not anodisable — tin, nickel or silver electroplate for solderability and tarnish control, or use chemical blackening/clear lacquer; polishes to a high lustre but oxidises quickly if unprotected.
C11300 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 |
|---|---|---|
| Ag8 troy oz/short ton minimum; C11400 = 10 oz, C11600 = 25 oz variants | ≥ 0.03 | 0.03 |
| Otypical tough-pitch oxygen level, not a specified limit | 0.02 – 0.05 | 0.03 |
| CuCu + Ag counted together, ASTM B152/B133; oxygen present as Cu2O | ≥ 99.9 (balance) | — |
C11300-H08 — frequently asked
What is C11300-H08 used for?
C11300-H08 is typically used for commutator bars, lead-in wires and motor conductors. In short: silver-bearing ETP copper; holds temper through soldering; full ETP conductivity.
What is the yield strength of C11300-H08?
C11300-H08 has a typical yield strength of 345 MPa (50 ksi) and a tensile strength of 380 MPa (55.1 ksi) — stronger than 73% of copper alloy grades. Strength varies by condition: see the 13 listed tempers.
Is C11300-H08 easy to machine?
Not especially — machinability is rated poor (34/100, worse than 53% of copper alloy grades). Gummy and stringy like ETP copper (≈20 % of free-cutting brass) — use sharp positive-rake tools, high speed, generous coolant, and avoid dwelling; consider C14500/C36000 if heavy machining dominates.
Can C11300-H08 be welded?
With care — weldability is rated fair (35/100). Resistance and brazing/soldering are excellent; fusion welding is compromised by the 0.02–0.05 % oxygen (porosity, hydrogen embrittlement) so prefer deoxidised C12200 filler, EB/laser or friction welding for critical joints.
What surface finishes work on C11300-H08?
Not anodisable — tin, nickel or silver electroplate for solderability and tarnish control, or use chemical blackening/clear lacquer; polishes to a high lustre but oxidises quickly if unprotected.
Can C11300-H08 be formed, bent or molded?
Annealed and 1/8–1/4 hard tempers deep draw, coin and bend to very tight radii; hard tempers need generous bend radii (≥1–2 t across grain) and interstage annealing at 400–600 °C.
What is the maximum service temperature of C11300-H08?
C11300-H08 is rated for continuous use to about 190°C (374 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C11300-H04 and C11300-O25?
H04 is the default condition — the workhorse stocked temper: full-hard strip/bar/rod that keeps its hardness through soldering thanks to the silver addition. O25: soft heavy plate/bar for deep forming, bending of busbars and welded fabrications. Yield strength is 310 MPa in H04 versus 62 MPa in O25.
Sources
- ASTM B152/B152M — Copper Sheet, Strip, Plate, and Rolled Bar — ASTM International (2019)
- ASTM B133 — Copper Rod, Bar, and Shapes — ASTM International (2020)
- CDA Alloy Database — C11300 Silver-Bearing Tough Pitch Copper — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- EN 13601 / CW011A copper designations — CEN (2013)
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.