| Alloy | Type | Conductivity* | Tensile* | Typical use |
|---|---|---|---|---|
| C194 / KFC (C19210) | Cu-Fe-P | ~60% IACS | 400–500 MPa | Power and harness terminals |
| C7025 | Cu-Ni-Si-Mg | ~40–45% IACS | 600–800 MPa | Fine-pitch signal terminals, board-to-board |
| C5210 / C5191 | Phosphor bronze | ~12–15% IACS | 500–600 MPa | Contacts, springs, switch fingers |
| C17200 | Beryllium copper | ~22–28% IACS | 1000–1400 MPa | Thin high-force springs, long mating life |
| C1990 | Titanium copper | ~15–20% IACS | 900–1100 MPa | High-reliability and automotive connectors |
| C7521 / C7701 | Nickel silver | ~6–9% IACS | 500–650 MPa | Shielding cans, decorative parts, antennas |
| C2680 / C2600 | Brass | ~27–28% IACS | 350–500 MPa | General terminals, hardware |
| C1100 | Copper | ~100% IACS | 200–380 MPa | High-conductivity parts, heat spreaders |
| SUS301 | Stainless | ~2–3% IACS | 1800 MPa+ full hard | Metal domes, springs, contact fingers |
| SUS304 | Stainless | ~2–3% IACS | 1200–1500 MPa full hard | Structural parts, housings, deep drawing |
* Industry-typical values, varying with temper and batch. Per-batch values are confirmed on the Mill Test Certificate.
| Downstream process | Temper | Reason |
|---|---|---|
| Deep drawing, complex forming | Annealed / 1/4H | Harder tempers crack |
| Bending beyond 90° | 1/2H or softer | Balances strength and ductility |
| No forming after stamping | H | Maintains contact force |
| Maximum spring force and fatigue life | EH / FH / T | Maximum elasticity |
For a first order, sample two or three tempers and confirm the final temper from measured springback after tool tryout. An enquiry that names an alloy but no temper will almost certainly be reworked at tooling stage.
C194 (CuFe2P) runs around 60% IACS with 400–500 MPa tensile and costs less — the right call for power terminals and automotive harness terminals where current is high but mating cycles are moderate. C7025 (CuNiSiMg) gives up conductivity (40–45% IACS) but reaches 600–800 MPa with far better stress relaxation resistance, holding spring force above 150°C.
Rule of thumb: high current → C194; high spring force and heat resistance → C7025. Below 0.4 mm pitch with more than 5,000 mating cycles, go straight to C7025.
Technically yes, commercially usually not. C17200 in the aged condition reaches 1000–1400 MPa — more than double C5210 at 500–600 MPa — with a higher elastic limit and fatigue life, at 3–5× the material cost.
It is justified in three cases only: the spring section must be very thin yet still deliver force; mating life exceeds 100,000 cycles; continuous operating temperature exceeds 150°C. Note that C17200 contains 1.8–2.0% beryllium — stamping and slitting dust carries occupational health risk and requires dust extraction.
The difference is work-hardening capacity, not corrosion resistance. SUS301 (6–8% Ni) work-hardens aggressively and reaches over 1800 MPa at full hard — the industry default for springs, metal domes and contact fingers. SUS304 (8–10% Ni) resists corrosion better but work-hardens less, typically 1200–1500 MPa at full hard, suiting structural parts, housings and deep-drawn parts rather than high-force springs.
Need spring force → 301. Need corrosion resistance and formability → 304. For both, consider SUS631 or passivation.
Four items: alloy and temper, thickness, width with tolerance, and coil weight or diameter. Also tell us the application and estimated annual volume — that determines whether we ship from stock or schedule a slitting run.
Without these the quotation can only be a range, and the lead time cannot be confirmed.
Drawing-based, sample-based and toll processing accepted. Small-lot sampling with multiple tempers for tool tryout.