EN
What Is C19400 Copper Strip? Composition, Standards and Where It Fits
If you buy copper strip for connectors, terminals or lead frames, you have probably seen C19400 quoted next to plain copper and brass, often at a similar price but with very different data behind it. This article covers what the alloy actually is, how it is designated in different standards, and where it belongs in a material shortlist.
A copper alloy defined by 2% iron
C19400 is a high-copper alloy containing roughly 2.1–2.6% iron, with small additions of phosphorus and zinc. The iron does not dissolve fully into the copper matrix; it forms finely dispersed particles that block dislocation movement and slow grain growth during heating. Phosphorus deoxidises the melt and helps control the size of those particles, and zinc improves resistance to tin whisker growth and softening after plating.
The practical result is a material that keeps a large part of copper's conductivity while behaving mechanically much closer to a structural alloy. It is commonly called iron copper, iron bronze or, from its European designation, CuFe2P.
Cross-standard designations
The same alloy appears under at least four naming systems. If you are comparing quotations from different regions, these are equivalent for most purposes:
Standard |
Designation |
Specification |
Region |
UNS / ASTM |
C19400 |
ASTM B465 |
North America |
EN |
CuFe2P / CW107C |
EN 1652, EN 1654 |
Europe |
JIS |
C1940 |
JIS H3100, JIS H3130 |
Japan |
GB/T |
C19400 (TFe2.5) |
GB/T 2059 |
China |
Note that ASTM B465 covers plate, sheet, strip and rolled bar, while EN 1652 and EN 1654 separate general-purpose product from material intended for springs and connectors. When a drawing calls out EN 1654, the temper and bend requirements are tighter than the general standard, so it is worth stating the specification and not only the alloy number on an enquiry.
Chemical composition
Limits per ASTM B465, in weight percent:
Element |
Content (%) |
Function |
Cu (incl. Ag) |
97.0 min. |
Base metal — conductivity |
Fe |
2.1 – 2.6 |
Dispersion strengthening, softening resistance |
P |
0.015 – 0.15 |
Deoxidiser, controls particle size |
Zn |
0.05 – 0.20 |
Improves plating and whisker behaviour |
Pb |
0.03 max. |
Impurity limit |
Physical properties
Property |
Metric |
Imperial |
Density |
8.78 g/cm³ |
0.317 lb/in³ |
Electrical conductivity |
60 – 65% IACS |
60 – 65% IACS |
Thermal conductivity |
approx. 260 W/(m·K) |
approx. 150 Btu/(ft·h·°F) |
Modulus of elasticity |
121 GPa |
17,500 ksi |
Thermal expansion (20–300°C) |
approx. 16.5 × 10⁻⁶ /K |
approx. 9.2 × 10⁻⁶ /°F |
Tensile strength (temper range) |
310 – 550 MPa |
45 – 80 ksi |
Two figures explain most of the alloy's popularity. Conductivity of 60–65% IACS is roughly two and a half times that of C26000 brass, and tensile strength in the harder tempers is well above what pure copper can reach. Equally important, C19400 holds its strength after the short thermal excursions of reflow soldering and plating bake-out, where pure copper would begin to anneal. The detail of that behaviour is the subject of the next article in this series.