C260 Brass Sheet vs C268, C510 Phosphor Bronze and C110 Copper for Stamped Connectors: What the Evidence Settles

Does the terminal's current-carrying cross-section rule C260 out?

The first screen is conductivity, because it decides whether C260 can carry the current at all. C260 brass is reported at approximately 28% IACS^12,16,20, while C110 ETP copper is reported at 100–101% IACS^15,20.

That places C110 roughly 3–4x more conductive than C260²⁰. The gap is a property of the alloy family, not a temper defect: zinc is added to copper to raise strength and hardness, and the same zinc addition reduces conductivity¹⁶.

A C260 terminal therefore needs a larger cross-section than a C110 terminal to carry the same current, and if the connector envelope or the terminal footprint is already fixed, that option may not exist.

Where the design is sized by conductivity rather than by force or form, C110 is the choice among the alloys compared here^15,20. The sources do not publish % IACS values for C268 or C510, so no conductivity comparison beyond C260 versus C110 can be drawn from this evidence.

Does the terminal need C510's spring and elevated-temperature behaviour instead of C260?

If the contact must hold force at temperature or survive many mating cycles, the decision shifts from conductivity to stress relaxation and fatigue. C510 phosphor bronze is positioned for wear, bearing, spring and high-temperature connector applications, with higher strength and better stress relaxation resistance than brass^15,18,22.

The mechanism is the tin content: tin in phosphor bronze improves stress relaxation resistance and strength, which is why C510 holds force where C260 and C110 begin to relax¹⁸. The reported relaxation figures point the same way.

C510 tolerates 125°C with about 3% force loss over 1,000 hours^8,11, while C260 loses about 8% at 100°C over the same duration¹¹. Above 150°C, even C510 enters rapid relaxation, with 15% force loss within 500 hours¹¹.

Fatigue strength at 10^7 cycles separates the alloys further: C510 spring temper is reported at 210 MPa, C260 half-hard at 140 MPa, and C110 annealed at 75 MPa²⁷. Those figures are vendor-tier observations, not industry limits, but they are the only relaxation and fatigue data in this set.

The cost side of the same trade-off is that the roughly 6% tin content in phosphor bronze is cited as the reason for its significantly higher material cost than brass¹⁸.

Which C260 temper delivers the strength without losing the elongation the die needs?

Within C260, temper choice sets the strength-formability balance, because cold work raises tensile strength and cuts elongation^12,24. The published C260 tempers span a wide band, and the buyer should pick the softest temper that meets the contact-force requirement rather than the hardest available.

C260 H02 is reported at 62 ksi tensile with 25% elongation, while H10 extra spring reaches 99 ksi with elongation falling to 3%²⁴. The same relationship is described across the alloy generally: annealed C260 is soft and highly formable, and cold-rolled tempers trade elongation for strength and hardness¹².

Because actual values depend on thickness, temper, standard and mill practice, the drawing should specify the exact temper and applicable standard rather than the generic alloy name¹². The sources do not publish yield or tensile values for C268 or C110 sheet, so this temper trade-off is documented for C260 only.

Will C260 and C110 both form acceptably in the stamping die?

Formability is the screen where C260 is competitive rather than disadvantaged. C260 is described as having excellent ductility and is listed among the alloys used for electrical terminals and connectors¹⁰, and it is characterised as having clean edges and stable springback²².

C110 copper is described as easy to form with little springback²², and both C260 and C110 are rated excellent formability with low springback in a general stamping context⁹.

The distinction is that C110's springback is described as minimal while C260's is described as stable, which matters for die compensation but not for whether the part can be formed.

Blanked edge quality differs by grain size: C260 at grain size 7 yields a 45–50% burnish zone, C110 at grain size 6 yields 35–40%, and C510 at grain size 8 yields 55–60%²⁹. Where the blanked edge becomes the contact surface, that burnish proportion affects how much secondary deburring the terminal needs²⁹.

Blanking clearance is set as a percentage of thickness, reported at 3–5% for phosphor bronze and 5–8% for annealed C110, with clearance below 3% accelerating punch wear and above 8% increasing burr height beyond 0.05 mm²⁹.

No source in this set publishes minimum bend radii or quantitative springback values for any of the four alloys, so those must come from forming trials or supplier data.

Compliance checks before C260 enters the approved-material list

C260 is lead-free and relevant to RoHS and REACH purchasing requirements, and it is not a free-machining brass because lead is not intentionally added^20,28. The checks below confirm that position for the specific heat and lot being supplied, since the sources describe the alloy generally rather than certifying a specific delivery.

• ✓Confirm the C260 heat is lead-free and RoHS/REACH-relevant for the intended product category.
• ✓Request a mill test certificate or material certification for the specific heat, lot and standard supplied.
• ✓Verify the drawing specifies the exact temper and applicable standard, not the generic alloy name.
• ✓Confirm the alloy is not a free-machining grade if the part is stamped rather than machined.

What to obtain from suppliers before the alloy choice can be costed or scheduled

The evidence carries no pricing, MOQ, lead-time or standard-number data for any of the four alloys, so the cost and availability comparison has to be built from supplier quotes rather than from published figures.

One supplier states it holds C11000, Brass 260 and phosphor bronze C51000 in thicknesses from 0.15 mm to 1.5 mm as in-house inventory¹⁷, and another states it can supply C26000 as coil, sheet, plate, rods, bars and sections¹⁰.

Those are supplier capability claims, not market availability data, and they do not cover C268 or C510 sheet stock generally.

• ✓Request per-kilogram or per-pound pricing for C260, C268, C510 and C110 sheet at the required thickness.
• ✓Ask for the price differential between C260 and C510, since the tin content is cited as the reason for C510's higher cost.
• ✓Confirm MOQ, standard stock sizes and lead time for each alloy at the required temper.
• ✓Ask whether the supplier holds the required thickness in stock or orders from the mill.
• ✓Request the applicable ASTM or EN standard number and any REACH declaration for each alloy.
• ✓Ask for forming trials or empirical stamping data on the specific temper, since standard tensile data does not capture work-hardening or springback.

Where the sources disagree or leave the figure open

What the sources do not establish

• No quantitative conductivity (% IACS) values for C268 or C510 were found.
• No yield strength or tensile strength values for C268 or C110 sheet were found.
• No minimum bend radius or quantitative springback data for any alloy.
• No per-pound or per-kilogram pricing or price differentials for any of the four alloys.
• No corrosion resistance data for C268, C510 or C110; only qualitative mention for C260.
• No MOQ, standard stock sizes or lead time data for any alloy.
• No specific ASTM/EN standard numbers or REACH certifications for the four alloys.
• No annealing-between-operations requirements for any alloy.
• No C268-specific data at all was found in the retrieved sources.