Copper Alloy C19025-HR08
Heat-treated state
UNS C19025
HR08 = spring hard and stress relieved
Special-order spring temper for flat contact springs where formability is minimal but contact force must be maximal.
Values for the HR08 condition
Other C19025 tempers and conditions
C19025 is listed in 7 conditions; see the grade overview at C19025.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick for deep-drawn or severely formed parts where strength is added later by the customer's own work hardening. | 180 | 380 | 25 | 105 HB | 48 % IACS |
Half hard | Cold-rolled half hard strip for forming-dominated parts that do not need the extra relaxation resistance of a stress-relief bake. | 430 | 500 | 10 | 148 HB | 43 % IACS |
Half hard and stress relieved | Choose when tight bends (small bend radii, complex terminal geometry) matter more than peak spring force. | 480 | 520 | 9 | 83 HRB | 46 % IACS |
Full hard | Straight cold-rolled hard strip; cheaper than the HR grades but with lower stress-relaxation resistance. | 510 | 565 | 6 | 166 HB | 42 % IACS |
HR04Default Full hard and stress relieved | The workhorse connector-strip temper: balanced spring force, bendability and stress-relaxation resistance. | 550 | 585 | 6 | 88 HRB | 45 % IACS |
Extra hard and stress relieved | Highest-strength stocked temper for miniature high-force contacts; bend radii must be generous and grain direction respected. | 610 | 635 | 4 | 92 HRB | 44 % IACS |
HR08This page Spring hard and stress relieved | Special-order spring temper for flat contact springs where formability is minimal but contact force must be maximal. | 655 | 680 | 3 | 14 HRC | 43 % IACS |
What is C19025-HR08?
C19025-HR08 is C19025 heat treated to HR08 — special-order spring temper for flat contact springs where formability is minimal but contact force must be maximal. C19025-HR08 has a yield strength of 655 MPa (95 ksi) and a tensile strength of 680 MPa (98.6 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 128 GPa (18.6 Msi). C19025-HR08 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,070°C (1,958 °F). HR04 is the default condition FabDigit quotes; HR08 is available on request or by drawing note.
Advantages
- High strength — 655 MPa (95 ksi), better than 96% of copper alloy grades
- High electrical conductivity — 43 % IACS, better than 75% of copper alloy grades
Limitations
- Limited ductility — 3%, worse than 97% of copper alloy grades
- Limited service temperature — 160°C (320 °F), worse than 92% of copper alloy grades
C19025-HR08 properties
Typical room-temperature values for C19025-HR08; 21 are specific to this condition. Other listed values are C19025 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C19025-HR08 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,070°C (1,958 °F).
Mechanical11
C19025-HR08 has a yield strength of 655 MPa (95 ksi) and a tensile strength of 680 MPa (98.6 ksi) — stronger than 96% of copper alloy grades. Elongation at break is 3% and the elastic modulus is 128 GPa (18.6 Msi).
Thermal6
C19025-HR08 is rated for continuous service to 160°C (320 °F). It conducts heat at 172 W/m·K (99.4 BTU/hr·ft·°F), better than 74% of copper alloy grades. Thermal expansion is 17.5 µm/m·K (9.72 µin/in·°F).
Electrical3
C19025-HR08 conducts electricity at 43 % IACS, better than 75% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C19025-HR08 takes about 57 MJ of energy and emits 3.9 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 30%.
Manufacturability7
C19025-HR08's machinability is fair (35/100, better than 51% of copper alloy grades); weldability fair (40/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C19025-HR08
Is C19025 easy to machine?
Gummy, non-leaded copper alloy — use sharp positive-rake carbide, high speed and flood coolant; mostly stamped rather than machined.
Can C19025 be welded?
Resistance and laser spot welding are practical; any fusion welding locally anneals the cold-worked temper and drops contact force.
Can C19025 be formed, bent or molded?
Progressive-die stamping of thin strip; bend with grain direction in mind (GW ≈ 0.3–0.5 t at HR02, ≥1 t at HR06) and stress-relief bake after severe forming.
What surface finishes work on C19025?
Not anodisable — standard finishes are reflow/matte tin, nickel underplate with gold or silver flash for contact surfaces.
C19025 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 |
|---|---|---|
| Niprincipal strengthener with Sn/P | 0.8 – 1.8 | 1 |
| Snsolid-solution strengthening, improves stress relaxation | 0.5 – 1.5 | 0.9 |
| Pforms Ni-P precipitates, deoxidiser | 0.01 – 0.15 | 0.05 |
| Znimpurity limit | ≤ 0.2 | — |
| Feimpurity limit | ≤ 0.1 | — |
| Cu96.0 % min including Ag; balance | balance | — |
C19025-HR08 — frequently asked
What is C19025-HR08 used for?
C19025-HR08 is typically used for automotive connectors, electronic terminals and battery contacts. In short: high-strength connector strip; stronger than C19020; 45 % IACS spring copper.
What is the yield strength of C19025-HR08?
C19025-HR08 has a typical yield strength of 655 MPa (95 ksi) and a tensile strength of 680 MPa (98.6 ksi) — stronger than 96% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C19025-HR08 easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of copper alloy grades). Gummy, non-leaded copper alloy — use sharp positive-rake carbide, high speed and flood coolant; mostly stamped rather than machined.
Can C19025-HR08 be welded?
With care — weldability is rated fair (40/100). Resistance and laser spot welding are practical; any fusion welding locally anneals the cold-worked temper and drops contact force.
What surface finishes work on C19025-HR08?
Not anodisable — standard finishes are reflow/matte tin, nickel underplate with gold or silver flash for contact surfaces.
Can C19025-HR08 be formed, bent or molded?
Progressive-die stamping of thin strip; bend with grain direction in mind (GW ≈ 0.3–0.5 t at HR02, ≥1 t at HR06) and stress-relief bake after severe forming.
What is the maximum service temperature of C19025-HR08?
C19025-HR08 is rated for continuous use to about 160°C (320 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C19025-HR04 and C19025-O60?
HR04 is the default condition — the workhorse connector-strip temper: balanced spring force, bendability and stress-relaxation resistance. O60: pick for deep-drawn or severely formed parts where strength is added later by the customer's own work hardening. Yield strength is 550 MPa in HR04 versus 180 MPa in O60.
Sources
- ASTM B888/B888M — Copper Alloy Strip for Use in Manufacture of Electrical Connectors or Spring Contacts — ASTM International (2020)
- CDA Alloy Registration — C19025 (Cu-Ni-Sn-P) — Copper Development Association (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- High-performance Cu-Ni-Sn-P connector strip (KLF-118 class) datasheet — Copper strip producer (2021)
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.