C19200 is a copper-iron-phosphorus (Cu-Fe-P) alloy, one of a family of precipitation-hardenable coppers developed for electrical and electronic hardware. It is supplied mainly as strip and sheet, and it fills the gap between annealed high-conductivity copper, which is too soft to hold a spring contact, and the stronger but much less conductive tin bronzes and nickel silvers.
What the Iron and Phosphorus Do
Iron has very limited solubility in copper at room temperature but is more soluble at high temperature, and phosphorus combines with iron to form fine precipitates on cooling or on a controlled ageing treatment. Those precipitates impede dislocation movement, so the alloy achieves higher strength and a much better resistance to softening than pure copper of the same conductivity class. Because the total addition is only a little over one percent, the penalty to conductivity is moderate, and the grade remains a genuinely high-conductivity material.
| Element | Content | Function |
|---|---|---|
| Copper including silver | 99.0% min | Matrix |
| Iron | 0.8-1.2% | Forms the strengthening precipitates |
| Phosphorus | 0.025-0.04% | Deoxidiser and precipitate former |
| Magnesium, tin | Trace, optional | Used in related grades only where specified |
Strip, sheet and rolled bar are ordered to ASTM B465, which states the composition limits, the temper designations and the mechanical property requirements for each temper. The Chinese grade designations for copper-iron alloys appear in GB/T 5231, and the corresponding Japanese strip designations are listed in the JIS copper and copper alloy strip standards.
Properties by Temper
| Temper group | Tensile strength | Typical behaviour |
|---|---|---|
| Soft annealed tempers | about 280-330 MPa | Highest elongation, used for deep drawing and severe forming |
| Half-hard and hard tempers | about 350-430 MPa | Good balance of formability and spring properties |
| Extra-spring tempers | up to about 480 MPa | Maximum strength for contact and spring parts |
The values above describe the band covered by the standard across soft to extra-spring tempers; the guaranteed minimum for each temper is stated in ASTM B465 and repeated on the mill certificate. Electrical conductivity is high, in the same class as the other low-alloyed Cu-Fe-P grades and well above the tin bronzes, and it is specified as a minimum for the temper supplied.
Resistance to softening is one of the practical reasons for choosing the grade. The alloy retains useful strength to approximately 350-400 deg C, which means it survives the soldering and reflow processes used in connector and lead frame assembly without losing contact force.
Heat Treatment and Hardening Route
C19200 is hardened by a combination of cold work and precipitation, not by the quench-and-temper cycle used for steel. Solution treatment dissolves iron and phosphorus, cold rolling develops the temper and orientates the structure, and a controlled ageing treatment precipitates the strengthening phase. The mill delivers strip in the finished temper, and users should not expect to develop properties by a shop heat treatment; the correct approach is to specify the temper and form the part without destroying it.
Applications
Integrated circuit lead frames and semiconductor package parts, where strength, conductivity and thermal performance are needed together.
Relay springs, switch components and contact springs that must retain force at slightly elevated temperature.
Connector terminals, sockets and crimp parts in automotive and industrial harnesses.
Heat-exchanger fins and tubes, radiator components and other heat-transfer parts that benefit from high thermal conductivity plus strength.
General electrical hardware where a material stronger than annealed copper is required without moving to a bronze or a nickel silver.
Selection, Forming and Inspection Points
Specify the temper, not just the grade: formability, springback and contact force all follow from the temper, and two suppliers can quote the same grade with very different properties.
Consider bending direction and grain direction. In heavily rolled tempers, the bend radius must be increased when the bend line runs across the rolling direction.
Plan soldering and reflow exposure within the softening temperature of the chosen temper, and check that the process window does not exceed approximately 350-400 deg C at the part.
Verify chemistry, temper and mechanical properties against ASTM B465 on the mill certificate, and add a conductivity test when the part carries current.
Where a related grade with a different iron or phosphorus level is offered as an alternative, compare the composition and property tables rather than the grade description alone.
FAQ
Q: Is C19200 hardened by heat treatment like steel?
No. It is strengthened by cold work combined with a precipitation treatment. There is no quench-and-temper cycle, and the final properties are set at the mill in the delivered temper.
Q: What is the difference between C19200 and C19400?
Both are copper-iron-phosphorus alloys. They differ in the level of iron and phosphorus and therefore in the balance of strength, conductivity and formability, so the property tables of the applicable standard should be compared for the specific application.
Q: Is C19200 suitable for high-temperature service?
It retains useful strength to approximately 350-400 deg C, which covers soldering, reflow and many connector duties. It is not intended for sustained high-temperature structural service.
Q: Which product forms are available?
Strip and sheet are the main forms covered by ASTM B465, and rolled bar is included in the same specification. Rod and wire in related Cu-Fe-P grades are covered by their own product standards.
Q: Why is a conductivity value quoted with the temper?
Because both cold work and precipitation affect conductivity. Quoting conductivity without the temper is meaningless; the standard fixes a minimum for each delivered condition.
Q: How should the material be stored and handled?
Keep strip in its original moisture-barrier packing, handle coils with edge protection, and avoid storage in humid or sulphur-bearing atmospheres that cause tarnishing before the forming operation.
