Copper Alloy C19020-HR04
Temper · default condition
UNS C19020
HR04 = full hard, cold rolled and stress relieved
The workhorse connector temper: best balance of ~520 MPa strength, formability and low stress relaxation.
Values for the HR04 condition
Other C19020 tempers and conditions
C19020 is listed in 7 conditions; see the grade overview at C19020.
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 that will be work-hardened or heat treated afterwards. | 140 | 320 | 32 | 52 HRB | 42 % IACS |
Half hard | Cold-rolled half-hard strip when maximum bendability matters more than relaxation resistance. | 380 | 425 | 12 | 123 HB | 41 % IACS |
Half hard, cold rolled and stress relieved | Choose when tight-radius bending (small R/t) is required together with good stress-relaxation resistance. | 410 | 450 | 13 | 131 HB | 46 % IACS |
Full hard | Cold-rolled hard strip for stamped parts that receive their own downstream thermal treatment. | 465 | 500 | 6 | 145 HB | 41 % IACS |
HR04DefaultThis page Full hard, cold rolled and stress relieved | The workhorse connector temper: best balance of ~520 MPa strength, formability and low stress relaxation. | 490 | 520 | 6 | 152 HB | 45 % IACS |
Extra hard, cold rolled and stress relieved | Higher contact force in thin gauges where only generous bend radii (or bend-good-way stamping) are used. | 545 | 570 | 4 | 166 HB | 45 % IACS |
Spring temper, cold rolled and stress relieved | Maximum yield strength and spring-back for high-force contact springs; least formable temper. | 590 | 610 | 3 | 180 HB | 44 % IACS |
What is C19020-HR04?
C19020-HR04 is C19020 in the HR04 temper — the workhorse connector temper: best balance of ~520 MPa strength, formability and low stress relaxation. C19020-HR04 has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 88% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 125 GPa (18.1 Msi). C19020-HR04 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Advantages
- High strength — 490 MPa (71.1 ksi), better than 88% of copper alloy grades
- High electrical conductivity — 45 % IACS, better than 77% of copper alloy grades
- Conducts heat well — 180 W/m·K (104 BTU/hr·ft·°F), better than 75% of copper alloy grades
Limitations
- Limited service temperature — 175°C (347 °F), worse than 92% of copper alloy grades
- Limited ductility — 6%, worse than 89% of copper alloy grades
C19020-HR04 properties
Typical room-temperature values for C19020-HR04; 15 are specific to this condition. Other listed values are C19020 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C19020-HR04 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 77% of copper alloy grades. It melts at 1,065°C (1,949 °F).
Mechanical12
C19020-HR04 has a yield strength of 490 MPa (71.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 88% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 125 GPa (18.1 Msi).
Thermal6
C19020-HR04 is rated for continuous service to 175°C (347 °F). It conducts heat at 180 W/m·K (104 BTU/hr·ft·°F), better than 75% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C19020-HR04 conducts electricity at 45 % IACS, better than 77% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C19020-HR04 takes about 57 MJ of energy and emits 3.8 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 35%.
Manufacturability7
C19020-HR04's machinability is poor (30/100, worse than 67% of copper alloy grades); weldability fair (45/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C19020-HR04
Is C19020 easy to machine?
Gummy like most low-alloy coppers — use sharp positive-rake carbide, high speed, generous coolant; chip breaking is poor, rate roughly 20 % of free-cutting brass.
Can C19020 be welded?
Resistance and laser welding of thin strip are routine; fusion welding softens the cold-worked temper locally and lowers spring force, so joints are usually crimped, welded at tabs, or soldered.
Can C19020 be formed, bent or molded?
Excellent progressive-die stamping and coining; bend R/t improves markedly in the stress-relieved HR tempers, but bad-way bends in HR06/HR08 need generous radii.
What surface finishes work on C19020?
Not anodizable — standard finishes are electrolytic tin, tin-lead-free reflow, nickel underlay with gold or palladium-nickel flash for contact areas.
C19020 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 |
|---|---|---|
| Nisolid-solution + phosphide strengthening | 0.8 – 1.8 | 1 |
| Snsolid-solution strengthening, relaxation resistance | 0.5 – 1.5 | 0.9 |
| Pforms Ni-P precipitates, deoxidizer | 0.01 – 0.1 | 0.05 |
| Cu97.0 % min Cu + named elements | balance | — |
C19020-HR04 — frequently asked
What is C19020-HR04 used for?
C19020-HR04 is typically used for electronic connectors, terminals and lead frames. In short: connector-grade spring copper; good stress-relaxation resistance; 45 % IACS at 520 MPa.
What is the yield strength of C19020-HR04?
C19020-HR04 has a typical yield strength of 490 MPa (71.1 ksi) and a tensile strength of 520 MPa (75.4 ksi) — stronger than 88% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C19020-HR04 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy like most low-alloy coppers — use sharp positive-rake carbide, high speed, generous coolant; chip breaking is poor, rate roughly 20 % of free-cutting brass.
Can C19020-HR04 be welded?
With care — weldability is rated fair (45/100). Resistance and laser welding of thin strip are routine; fusion welding softens the cold-worked temper locally and lowers spring force, so joints are usually crimped, welded at tabs, or soldered.
What surface finishes work on C19020-HR04?
Not anodizable — standard finishes are electrolytic tin, tin-lead-free reflow, nickel underlay with gold or palladium-nickel flash for contact areas.
Can C19020-HR04 be formed, bent or molded?
Excellent progressive-die stamping and coining; bend R/t improves markedly in the stress-relieved HR tempers, but bad-way bends in HR06/HR08 need generous radii.
What is the maximum service temperature of C19020-HR04?
C19020-HR04 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C19020-HR04 and C19020-O60?
HR04 is the default condition — the workhorse connector temper: best balance of ~520 MPa strength, formability and low stress relaxation. O60: pick for deep-drawn or severely formed parts that will be work-hardened or heat treated afterwards. Yield strength is 490 MPa in HR04 versus 140 MPa in O60.
Sources
- ASTM B888 / B465-class copper alloy strip for electrical connectors — ASTM International (2020)
- CDA/UNS Standard Designations for Wrought Copper Alloys (C19020) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Cu-Ni-Sn-P high-performance connector strip datasheet — Wieland / Kobe Steel (comparable grades) (2022)
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.