Copper Alloy C19700-H04
Supply condition · default condition
UNS C19700
H04 = full hard
The standard stocked temper: best all-round balance of spring force, formability and 80% IACS conductivity for connectors and lead frames.
Values for the H04 condition
Other C19700 tempers and conditions
C19700 is listed in 8 conditions; see the grade overview at C19700.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Choose for deep drawing or severe forming where strength is developed later by forming/stress relief. | 130 | 275 | 30 | 35 HRB | 82 % IACS |
Quarter hard | Choose when forming severity is high but some added stiffness over annealed strip is needed. | 250 | 315 | 18 | 95 HB | 81 % IACS |
Half hard | Choose for stamped contacts and terminals needing tight-radius bends with moderate spring force. | 310 | 350 | 12 | 65 HRB | 80 % IACS |
H04DefaultThis page Full hard | The standard stocked temper: best all-round balance of spring force, formability and 80% IACS conductivity for connectors and lead frames. | 385 | 415 | 6 | 72 HRB | 80 % IACS |
Extra hard | Choose when higher contact force is required and bends are gentle or in the good-way (GW) direction. | 425 | 450 | 4 | 78 HRB | 79 % IACS |
Mill hardened, full hard | Choose when improved bend formability and low springback drift are needed at a given strength; low-temperature stress relief after rolling raises conductivity and relaxation resistance. | 440 | 460 | 5 | 140 HB | 84 % IACS |
Spring hard | Choose for spring contacts and clips needing high yield and good stress-relaxation resistance with simple forming. | 455 | 480 | 3 | 82 HRB | 79 % IACS |
Extra spring hard | Highest strength temper — pick for maximum contact normal force in flat or lightly formed parts. | 490 | 510 | 2 | 85 HRB | 78 % IACS |
What is C19700-H04?
C19700-H04 is C19700 supplied in the H04 condition — the standard stocked temper: best all-round balance of spring force, formability and 80% IACS conductivity for connectors and lead frames. C19700-H04 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 78% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 120 GPa (17.4 Msi). C19700-H04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,075°C (1,967 °F).
Advantages
- Conducts heat well — 320 W/m·K (184.9 BTU/hr·ft·°F), better than 84% of copper alloy grades
- High electrical conductivity — 80 % IACS, better than 84% of copper alloy grades
- High strength — 385 MPa (55.8 ksi), better than 78% of copper alloy grades
Limitations
- Limited ductility — 6%, worse than 89% of copper alloy grades
C19700-H04 properties
Typical room-temperature values for C19700-H04; 13 are specific to this condition. Other listed values are C19700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C19700-H04 has a density of 8.89 g/cm³ (0.321 lb/in³), heavier than 72% of copper alloy grades. It melts at 1,075°C (1,967 °F).
Mechanical11
C19700-H04 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 78% of copper alloy grades. Elongation at break is 6% and the elastic modulus is 120 GPa (17.4 Msi).
Thermal6
C19700-H04 is rated for continuous service to 200°C (392 °F). It conducts heat at 320 W/m·K (184.9 BTU/hr·ft·°F), better than 84% of copper alloy grades. Thermal expansion is 17.6 µm/m·K (9.78 µin/in·°F).
Electrical3
C19700-H04 conducts electricity at 80 % IACS, better than 84% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 76% of copper alloy grades.
Sustainability4
Producing a kilogram of C19700-H04 takes about 57 MJ of energy and emits 3.8 kg of CO₂ — less than 52% of copper alloy grades. Typical recycled content is 30%.
Manufacturability7
C19700-H04'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 C19700-H04
Is C19700 easy to machine?
Gummy like pure copper (≈20% of AISI 1212) — use sharp positive-rake tools, high speed, flood coolant; stamping and progressive-die blanking are the normal removal routes.
Can C19700 be welded?
Excellent for resistance, laser and ultrasonic welding of thin strip; fusion arc welding is impractical due to high thermal conductivity and P/Mg loss.
Can C19700 be formed, bent or molded?
Formability drops sharply above H04 — specify GW/BW minimum bend radius (typically 0–1t at H02, 2–4t at H08/H10) and consider stress relief after forming to cut springback drift.
What surface finishes work on C19700?
Not anodizable; standard finishes are hot-dip or reflow tin, nickel underplate with gold or silver flash for contacts, or bare with anti-tarnish (BTA) coating.
C19700 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 |
|---|---|---|
| Feforms fine Fe-rich/phosphide precipitates | 0.3 – 1.2 | 0.6 |
| P | 0.1 – 0.4 | 0.2 |
| Mgimproves stress-relaxation resistance | 0.01 – 0.2 | 0.05 |
| Pbimpurity limit | ≤ 0.03 | — |
| Znimpurity limit | ≤ 0.2 | — |
| CuCu + named elements ≥ 99.8%; Cu ≥ 99.0% incl. Ag | balance | — |
C19700-H04 — frequently asked
What is C19700-H04 used for?
C19700-H04 is typically used for springs and connectors, electrical terminals and relay contacts. In short: high-conductivity spring copper; 80% IACS at 415 MPa; stress-relaxation resistant strip.
What is the yield strength of C19700-H04?
C19700-H04 has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 415 MPa (60.2 ksi) — stronger than 78% of copper alloy grades. Strength varies by condition: see the 8 listed tempers.
Is C19700-H04 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 67% of copper alloy grades). Gummy like pure copper (≈20% of AISI 1212) — use sharp positive-rake tools, high speed, flood coolant; stamping and progressive-die blanking are the normal removal routes.
Can C19700-H04 be welded?
With care — weldability is rated fair (45/100). Excellent for resistance, laser and ultrasonic welding of thin strip; fusion arc welding is impractical due to high thermal conductivity and P/Mg loss.
What surface finishes work on C19700-H04?
Not anodizable; standard finishes are hot-dip or reflow tin, nickel underplate with gold or silver flash for contacts, or bare with anti-tarnish (BTA) coating.
Can C19700-H04 be formed, bent or molded?
Formability drops sharply above H04 — specify GW/BW minimum bend radius (typically 0–1t at H02, 2–4t at H08/H10) and consider stress relief after forming to cut springback drift.
What is the maximum service temperature of C19700-H04?
C19700-H04 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C19700-H04 and C19700-O60?
H04 is the default condition — the standard stocked temper: best all-round balance of spring force, formability and 80% IACS conductivity for connectors and lead frames. O60: choose for deep drawing or severe forming where strength is developed later by forming/stress relief. Yield strength is 385 MPa in H04 versus 130 MPa in O60.
Sources
- CDA Alloy Datasheet C19700 — Copper Development Association (copper.org) (2023)
- ASTM B888/B888M — Copper Alloy Strip for Electrical Connectors — ASTM International (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (Copper) — ASM International (2005)
- GB/T 2059 / GB/T 2040 (2017)
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.