What is the real difference between C17200 and C17300?

Beryllium content is identical (1.8–2.0%). C17300 adds 0.20–0.60% lead, which is an internal lubricant that breaks chips and cuts tool wear. Same strength ceiling, far better automatic-lathe machinability. C17300 is the free-machining version of C17200.

Can I substitute C17510 for C17200 to cut cost?

Only if conductivity or heat dissipation matters more than load. C17510 runs roughly half to two-thirds the tensile and yield of C17200, so it will not survive the same spring, fatigue, or wear duty. Use it where current path or thermal management is the primary job, not where strength is.

Does the lead in C17300 create a hazard in finished parts?

Finished solid C17300 parts pose no known health risk in normal handling. The hazard is airborne dust from machining, grinding, or welding — and C17300 adds lead dust on top of beryllium particulate. Use ventilation and follow OSHA 29 CFR 1910.1024 during fabrication.

Which grade handles high-temperature spring duty best?

C17300. Its cobalt-rich chemistry resists stress relaxation better than C17200, so it holds preload at elevated temperature — downhole tools and engine-bay springs are its primary application range. C17510 softens the soonest above ~250–300°C.

Is C17510 the same as C17500?

No. C17500 is a high-conductivity, high-beryllium grade (low nickel); C17510 is CuNi2Be — low beryllium, high nickel. Different UNS numbers, different chemistry, different tempers. They are not drop-in substitutes, and C17510 is the one covered in this guide.

Does Linsy supply these beryllium copper grades?

Yes — Linsy supplies C17200, C17300, and C17510 in sheet, plate, bar, and tube forms with full MTR/MTC documentation per lot. Reach out with your grade, form, and temper requirements for lead time and documentation options.

Beryllium Copper Guide: C17200 vs C17300 vs C17510

C17200, C17300, and C17510 divide into two property camps — high-beryllium (≈2% Be) for maximum strength and fatigue resistance, and low-beryllium nickel-beryllium (CuNi2Be) for conductivity and thermal performance. C17510 sits in a separate band: roughly half the strength of C17200/C17300, but double the conductivity. Selection depends on the primary constraint: load, fatigue cycles, machining volume, service temperature, or current capacity.

Composition: What Actually Separates Them

Element	C17200	C17300	C17510
Beryllium (Be)	1.80–2.00%	1.80–2.00%	0.20–0.60%
Nickel (Ni)	0.20% min (as Co+Ni)	0.20–0.60% (Co+Ni)	1.40–2.20% (ASTM wide band; some sources quote 1.80–2.20%)
Cobalt (Co)	Part of Co+Ni, ≤0.60% total	Cobalt-dominant in Co+Ni	≤0.30%
Lead (Pb)	None	0.20–0.60%	None
Copper	Balance	Balance	Balance

Two camps, one dividing line. C17200 and C17300 are both CuBe2-class alloys — same 1.8–2.0% beryllium, same precipitation-hardening mechanism, same strength ceiling. C17300 only differs by adding 0.20–0.60% lead as an internal lubricant, which is what makes it the free-machining member of the family. C17510 (CuNi2Be) drops beryllium to 0.20–0.60% and pushes nickel to 1.40–2.20%. Nickel, not beryllium, does the strengthening — so it lands in a completely different property band.

Property Comparison (Age-Hardened Typical)

Property	C17200	C17300	C17510
Tensile strength	1,130–1,550 MPa	1,130–1,400 MPa	750–970 MPa
Yield strength (0.2%)	890–1,240 MPa	~1,030–1,240 MPa	650–870 MPa
Hardness	36–45 HRC	36–43 HRC	28–33 HRC (≈ HRB 92–100)
Electrical conductivity	18–28% IACS	17–28% IACS	45–60% IACS
Thermal conductivity	~105–135 W/m·K	~105 W/m·K	~167–260 W/m·K
Density	8.25–8.36 g/cm³	8.25–8.40 g/cm³	8.75–8.83 g/cm³
Machinability (vs brass 100)	~20	50–80	30–40
High-temp / stress relaxation	Good	Better (Co-rich)	Fair (softens above ~250–300°C)
Elasticity / fatigue	Top-tier	Near C17200, better hot fatigue	Moderate

C17200 and C17300 share the same tensile and hardness ceiling; the real difference is machinability — C17300 jumps from rating ~20 to 50–80. C17510 is the outlier: about half the tensile and yield of C17200, but its conductivity (45–60% IACS) and thermal path (up to ~260 W/m·K) roughly double the high-Be grades. That is the entire reason it exists — carry current and heat while still holding a load.

Go/No-Go: Which Grade for Your Job

Each entry gives the trigger condition. Check whether your part hits it.

Stamping, bending, or forming with minimal machining, and the highest strength/elasticity is required → select C17200. Forming does the work; machining stays light. This is the highest elastic performance in the comparison.
C17200-level strength needed, but the part will be turned, milled, drilled, or threaded in volume on automatic lathes → select C17300. The 0.20–0.60% lead addition breaks chips and cuts tool wear. Automatic-lathe efficiency jumps versus fighting C17200’s gumming and burr formation.
Elevated-temperature spring duty where preload must hold over time → select C17300. Its cobalt-rich chemistry relaxes slower at temperature than C17200, so it keeps preload where the base grade would creep.
Significant current or heat dissipation required alongside a structural load → specify C17510. This is the only one of the three that pairs moderate strength (750–970 MPa) with 45–60% IACS and a strong thermal path. If the part must carry current or shed heat while holding shape, nothing else in this lineup works.
High-cycle precision spring where conductivity is irrelevant → select C17200 (or C17300 only if heavy machining is also involved). C17510 is the wrong call — its fatigue ceiling and elasticity sit a tier below.

Machining and Heat Treatment

All three grades follow solution-anneal → quench → age-hardening, but the temperature windows and shop-floor behavior diverge enough to change the manufacturing plan.

Parameter	C17200	C17300	C17510
Solution anneal	~790°C	~790°C	~790°C
Age-hardening	~315°C, 2–3 h	~315°C, 2–3 h (cited as wider window)	~340–360°C
Machinability (vs brass = 100)	~20 — gums tools, large burrs	50–80 — lead breaks chips cleanly	30–40 — no lead, no gumming
Formability (annealed state)	Stamps and bends well	Stamps and bends well	Good — low Be keeps it ductile
Solder / braze compatibility	Fair	Fair	Better (higher Ni content)
Manufacturing fit	Poor fit for automatic turning; avoid if design needs many drilled/tapped features	~30% higher throughput on Swiss-type parts (industry estimate); best for multi-feature precision parts	Moderate — below C17300 but above C17200

Where They Land in Production

The Go/No-Go above answers “should I use it?” This section maps each grade to its typical deployment areas once the part function is known.

C17200 (highest-volume high-strength BeCu): phone and connector springs, switch contacts, plastic-injection mold inserts, non-sparking tools, bellows, aerospace flexures, general-purpose probes.

C17300 (precision-machined high-strength BeCu): micro probes, medical micro-parts, downhole oil-and-gas tools, automatic-lathe terminals, multi-cavity mold details, parts requiring frequent drilling and tapping.

C17510 (high-conductivity nickel-beryllium): high-power connectors, EV current-carrying terminals, die-casting plunger tips, resistance-weld electrodes, heat-sink bases, semiconductor fixtures, high-current switch contacts.

Standards and Traceability

Grade	ASTM Designations	European Equivalent	Temper Codes
C17200	B196 (rod/bar), B441 (bus bar/shapes)	CW101C	TB00 (solution-annealed), TF00 / TH04 (age-hardened)
C17300	B196 (rod/bar), B441 (bus bar/shapes)	CW101C †	TB00, TF00, TH04
C17510	B937 / B944 (tube), B870	CW110C (CuNi2Be)	TB00, TF00, TH04

C17300 shares CW101C with C17200; lead addition does not change the EN designation.

Always specify: grade, temper, and MTR/MTC per lot — beryllium content drives the aging response, so heat-lot traceability matters for reproducible strength.

Sourcing Beryllium Copper from Linsy

Linsy Copper is ISO 9001/14001/45001 certified and supplies beryllium copper across C17200, C17300, and C17510 in sheet, plate, bar, and tube forms. Because beryllium content drives the aging response, heat-lot traceability matters: every order ships with full MTR/MTC documentation including chemical composition data, so the aging window is verifiable per lot. For C17300 specifically, the 0.20–0.60% lead content raises compliance questions in some regions — SGS RoHS and REACH SVHC reports are available on request to confirm regulatory status. Low-MOQ custom production runs process in 10–60 days depending on grade, size, and specification, which fits trial batches of spring strip, machined probes, or weld electrodes before volume commitment.

Conclusion

C17200, C17300, and C17510 are not three flavors of the same alloy — they split into a high-strength camp and a high-conductivity camp, and the cost order runs C17300 > C17200 > C17510 (more beryllium costs more). C17200 is the default for maximum strength with light machining; C17300 is that same strength with automatic-lathe machinability; C17510 is the half-strength, double-conductivity grade for parts that must also carry current or heat.

The trade-off is that beryllium copper stock is tight at most mills — high-beryllium grades face supply constraints, leaded C17300 triggers compliance checks in some regions, and trial quantities are hard to source without a mill relationship. Linsy stocks C17200, C17300, and C17510 in sheet, plate, bar, and tube, with low-MOQ custom production (10–60 day lead time) and full MTR/MTC documentation per lot — so the grade decision doesn’t stall on availability or traceability. Send the drawing or specification for a grade-fit review and quote, or compare C17200, C17300, and C17510 options side by side with Linsy’s technical team.

FAQ

Beryllium content is identical (1.8–2.0%). C17300 adds 0.20–0.60% lead, which is an internal lubricant that breaks chips and cuts tool wear. Same strength ceiling, far better automatic-lathe machinability. C17300 is the free-machining version of C17200.
Only if conductivity or heat dissipation matters more than load. C17510 runs roughly half to two-thirds the tensile and yield of C17200, so it will not survive the same spring, fatigue, or wear duty. Use it where current path or thermal management is the primary job, not where strength is.
Finished solid C17300 parts pose no known health risk in normal handling. The hazard is airborne dust from machining, grinding, or welding — and C17300 adds lead dust on top of beryllium particulate. Use ventilation and follow OSHA 29 CFR 1910.1024 during fabrication.
C17300. Its cobalt-rich chemistry resists stress relaxation better than C17200, so it holds preload at elevated temperature — downhole tools and engine-bay springs are its primary application range. C17510 softens the soonest above ~250–300°C.
No. C17500 is a high-conductivity, high-beryllium grade (low nickel); C17510 is CuNi2Be — low beryllium, high nickel. Different UNS numbers, different chemistry, different tempers. They are not drop-in substitutes, and C17510 is the one covered in this guide.
Yes — Linsy supplies C17200, C17300, and C17510 in sheet, plate, bar, and tube forms with full MTR/MTC documentation per lot. Reach out with your grade, form, and temper requirements for lead time and documentation options.