C194 (CuFe2P) contains roughly 2.1–2.6% iron and offers about 60% IACS with 400–500 MPa tensile strength at lower cost — the right choice for power terminals and automotive harness terminals where current is high but mating cycles are moderate.
C7025 (CuNiSiMg) gives up conductivity at 40–45% IACS but reaches 600–800 MPa with markedly better stress relaxation resistance, holding spring force above 150°C. It suits high-density, fine-pitch, high-cycle signal terminals and board-to-board connectors.
High current → C194; high spring force and heat resistance → C7025. Below 50 mating cycles and cost-sensitive, C194 is usually sufficient. Below 0.4 mm pitch with more than 5,000 cycles, go straight to C7025.
Technically yes, commercially usually not. C17200 aged reaches 1000–1400 MPa against C5210 at 500–600 MPa, with higher elastic limit and fatigue life, at three to five times the material cost.
Beryllium copper is justified in three cases: the spring must be very thin and still deliver force (SIM trays, precision connectors); mating life above 100,000 cycles; continuous temperature above 150°C.
Otherwise C5210 or C5191 is sufficient. Note that C17200 contains 1.8–2.0% beryllium — stamping and slitting dust carries occupational health risk and requires dust extraction. If a customer simply heard that beryllium copper is better, sample C5210 at H or EH first.
The difference is work-hardening capacity, not corrosion resistance. SUS301 (6–8% Ni) reaches over 1800 MPa at full hard — the default for springs, metal domes and contact fingers. SUS304 (8–10% Ni) resists corrosion better but hardens less, typically 1200–1500 MPa, suiting structural parts, housings and deep-drawn parts.
Spring force → 301; corrosion resistance and formability → 304. For humid or salt-spray environments that also need spring force, consider SUS631 or passivation.
Temper determines strength versus formability and is the most commonly omitted item on a quotation — and the most common cause of rework. The sequence from soft to hard is annealed, 1/4H, 1/2H, H, EH, FH/T. The same alloy can differ by more than 2× in tensile strength by temper alone.
Parts still requiring deep drawing or bending beyond 90° need 1/2H or softer to avoid cracking. Contacts with no further forming use H or EH. Springs needing maximum elasticity use FH/T.
On a first order, sample two or three tempers and confirm by measured springback after tool tryout. Every enquiry specifying alloy without temper will almost certainly be reworked at tooling stage.
A shielding can must satisfy welding, deep drawing, shielding effectiveness and cost simultaneously, and nickel silver balances all four. Stainless steel conducts at only 2–3% IACS and shields mainly by reflection, performing worse at high frequency. Worse, its solderability and plateability are poor, which rules it out for cans soldered to the PCB for grounding.
Nickel silver C7521 and C7701 give 6–9% IACS with 10–18% nickel for some magnetic shielding, plus corrosion resistance, deep drawability, solderability and a white appearance, at a fraction of beryllium or titanium copper cost.
One caveat: shielding effectiveness is driven mainly by structure — gap control, grounding points, cavity depth. Getting the geometry right with nickel silver usually beats switching to a more expensive alloy.
Yes for mid-range cans and decorative parts, typically 20–30% cheaper depending on temper and gauge. ZSNH, ZN36, KU360, KU400 and KU570 were developed to replace nickel silver with similar colour, density, strength, formability and conductivity in the same order of magnitude.
Three gaps: slightly lower corrosion resistance, so long-term reliability in salt spray or high humidity trails C7521; a narrower soldering window requiring reflow re-qualification; and drawings from Japanese and automotive electronics customers that specify C7521 directly, making substitution a formal change-control process.
Supply samples for salt-spray and solderability validation first, then discuss substitution. Never quote it as a drop-in without qualification.
Not necessarily; it depends on frequency. Electric-field shielding relies on conductivity for reflection loss; magnetic-field shielding relies on permeability for absorption loss.
High-nickel materials such as nickel silver and permalloy perform better against low-frequency magnetic fields from tens of kHz to a few MHz. At GHz frequencies used by WiFi and 5G, reflection dominates and high-conductivity copper or tin-plated copper wins.
Nickel silver is sufficient for phone and WiFi module cans; high-nickel or permalloy is needed near transformers and inductors; high-frequency designs often do best with tin-plated phosphor bronze or copper-nickel composites. Identify the interference band first, then select the material.
It comes down to rate capability and welding requirements — performance versus cost. Pure nickel Ni200 and Ni201 conduct at roughly 20–25% IACS with low resistance and heating, and weld reliably to aluminium or nickel tabs, making them the default for high-rate, power battery and long-reliability applications. The downside is price and nickel price exposure.
Nickel-plated steel uses a low-carbon steel core with a nickel layer improving contact resistance and solderability at 30–50% of the cost, suitable for low-rate consumer cells, though the steel core brings higher resistance and noticeable heating at high current.
Above 3C, or tabs over 30 mm, go pure nickel. Below 1C with short tabs, plated steel is adequate. For export orders confirm whether the customer specifies the substrate; Japanese and Korean accounts frequently mandate pure nickel.
Consumer lithium-ion copper foil is mainly 6–9 μm; power battery foil has moved from 8 μm toward 6 μm and even 4.5 μm; aluminium cathode foil is typically 12–16 μm.
Thinner foil raises energy density and lowers unit cost, but demands tighter tension control in coating and winding and increases breakage risk. It is not automatically better: where equipment precision cannot keep up, yield loss at 6 μm can consume the entire material saving.
Also note two distinct products: lithium battery copper foil (current collector, electrodeposited, micrometre scale) and rolled copper foil for shielding and conduction (from 0.005 mm). Different process routes, never quoted interchangeably.
Stainless steel goes to 0.005 mm; copper alloys typically start at 0.015 mm; copper and aluminium foil is supplied in coil. Width tolerance is controlled by gauge and width band, generally within ±0.05 mm for ultra-thin strip, tighter on request.
Ultra-thin delivery capability depends not only on the slitting line but on incoming flatness, tension control and packaging. Below 0.01 mm, a few newtons of tension variation causes wrinkling, and transport vibration can leave marks. Such orders normally require the customer to confirm packaging (paper or plastic core, coil diameter, interleaving) with acceptance criteria written into the contract.
For a first enquiry provide four items: alloy and temper, thickness, width with tolerance, and coil weight or diameter.
Overall plating covers the full strip surface — simplest process, but precious metal dominates cost. Suits parts that conduct or solder across their whole area.
Selective plating deposits continuously on a defined band (one side, a stripe, or a fixed distance from the edge) while the remainder stays bare — used where only the contact area needs gold and the solder legs need tin, saving substantial gold.
Spot plating deposits at discrete points matched to the stamping pitch, aligning plating positions one-to-one with contact locations in the tool. Highest precision and the greatest precious metal saving, but it requires exact pitch, feed direction and position tolerance — change any of the three and the plating mask must be rebuilt.
Guidance: low contact count with high precious metal cost → spot; terminals → selective; structural parts and shielding cans → overall nickel or tin.
Yes, per functional zone on the drawing, with an inspection report by X-ray fluorescence and cross-section verification where required.
Typical ranges: gold 0.05–0.3 μm for contact areas, 0.5 μm or more with a nickel underplate for wear zones; silver 1–5 μm for conduction and soldering, with attention to sulphide tarnishing; nickel 1–3 μm as a diffusion barrier underplate; tin 3–10 μm for solderability, too thin oxidising and too thick risking whiskers.
Two practical points: the tolerance band matters more than the nominal value (gold at ±0.02 μm versus ±0.1 μm is a different cost order), so agree it before quoting; and agree whisker-control requirements on tin-plated parts up front, since automotive and aerospace accounts usually require it.
Sampling is available, tiered by alloy and gauge. Standard alloys can often start from a few kilograms, and 1 kg level samples can be arranged depending on stock and minimum slitting coil weight.
One industry convention worth stating plainly: sampling is not free. Slitting has a minimum coil weight, and ultra-thin material consumes line time for tool changes, threading and tension setup, so small-lot unit cost runs well above volume pricing. Samples are normally charged at small-lot rates and credited against the volume order.
Send alloy, temper, thickness, width, application and estimated annual volume, and we will confirm whether it ships from stock or requires a slitting run.
Standard alloys ship from stock in Kunshan, typically 2–5 days within East China; slitting or plating runs usually take 7–15 working days; ultra-thin or special alloys require incoming material confirmation. Export orders add clearance and booking, roughly 7–12 days to Southeast Asian ports.
HS classification: 7409 / 7410 for copper, 7219 / 7220 for stainless, 7506 for nickel, 7606 for aluminium, 8108 for titanium. Three compliance points: China's export tax rebate on copper materials has been cancelled and is now treated as domestic sales, so the tax burden must be priced in; the US applies Section 232 duties on copper at 50% plus Section 301, leaving no realistic price competitiveness; beryllium copper is generally not a controlled dual-use item since the threshold is beryllium content above 50% while beryllium copper is about 2%, though composition must still be declared accurately.
Current recommendation: focus on Southeast Asia, the Middle East and India, quoting FOB Shanghai or Ningbo.
Standard deliverables: Mill Test Certificate with chemical composition and mechanical properties, plating thickness inspection report, RoHS declaration of conformity, REACH SVHC screening statement, and batch traceability by heat number and coil number.
Two lessons. First, RoHS and REACH reports must match the actual alloy — alloying elements differ across grades (beryllium copper contains beryllium, some brasses contain lead), so a generic report will be rejected at incoming inspection. Second, at customer audits and annual reviews, documentation completeness often decides renewals more than price, especially with automotive and medical accounts.
Recommendation: assemble a versioned document pack, refreshed quarterly, and send it proactively at enquiry stage.
Send the alloy, drawing or application and we will answer against your actual conditions rather than a generic script.