C172 Beryllium Copper vs C510 Phosphor Bronze
C172 beryllium copper and C510 phosphor bronze are both copper-based spring and contact alloys, but they sit at very different strength levels. C172 is the highest-strength copper alloy available, age-hardenable to over 1300 MPa nominal tensile for demanding springs, molds and non-sparking tools. C510 is a tougher, lower-cost wrought phosphor bronze for springs, electrical contacts and bushings.
The verdict
Choose C172 beryllium copper when you need maximum strength, hardness and spring performance — heat-treatable to ~1300 MPa nominal — for precision springs, connectors and injection-mold inserts. Choose C510 phosphor bronze for general-duty springs, contacts and bushings where its ~470 MPa nominal tensile is enough, beryllium handling is unwanted, and lower cost matters.
Side-by-side data
| Property | C172 Beryllium Copper | C510 Phosphor Bronze |
|---|---|---|
| Category | Copper Alloy | Copper Alloy |
| Density (g/cm³) | 8.25 | 8.86 |
| Tensile strength (MPa) | 1300 | 470 |
| Yield strength (MPa) | 1100 | 410 |
| Elongation (%) | 4 | 15 |
| Hardness | 40 HRC | 85 HRB |
| Max service temp (°C) | 200 | 225 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 105 | 69 |
| Typically used for | Springs & non-sparking tools | Springs, contacts & bushings |
Which should you choose?
Choose C172 Beryllium Copper when…
- You need the highest-strength copper alloy — age-hardenable to ~1300 MPa tensile and ~40 HRC nominal
- Springs and contacts must resist relaxation and hold high contact force over many cycles
- Non-sparking tools are required for explosive or flammable environments
- Mold inserts and cores need high conductivity plus high hardness to pull heat and resist wear
- Parts can be machined soft then age-hardened to final properties
- Higher cost (4.5 vs 3.0) is justified by the strength and fatigue performance
Choose C510 Phosphor Bronze when…
- Moderate spring force and good fatigue life are enough — no need for BeCu's extreme strength
- You want to avoid beryllium-dust handling and machining precautions entirely
- Bushings and bearings benefit from phosphor bronze's wear resistance and low-friction surface
- Good corrosion resistance (4.0) for contacts and marine-adjacent hardware is needed
- Lower material cost (3.0 vs 4.5) helps high-volume contact or terminal parts
- Parts are stamped or formed from strip without a heat-treat step
Key differences that matter
- C172 is the strongest copper alloy here — ~1300 MPa tensile / ~1100 MPa yield nominal after age hardening, versus C510's ~470/410 MPa.
- C172 is age-hardenable: machine or form it soft, then heat-treat to final hardness (~40 HRC nominal). C510 gets strength from cold work only.
- Beryllium copper requires controlled dust/fume handling during machining and grinding — a real shop-safety consideration C510 avoids.
- C510 offers slightly higher corrosion resistance (4.0 vs 3.5) and a higher max-temp rating (225°C vs 200°C nominal).
- Both are classic spring and electrical-contact materials; C172 is chosen when relaxation resistance and force density are critical.
- C172 retains useful thermal conductivity (~105 W/m·K nominal), making it valuable for mold cores that must both pull heat and resist wear.
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Open the Material SelectorGet a Quote →Frequently asked questions
Why is beryllium copper considered hazardous to machine?
Machining, grinding or welding C172 can generate fine beryllium-bearing dust and fumes that are hazardous if inhaled. Shops handle it with local exhaust, wet processes and respiratory controls. The finished solid part is safe to handle; the risk is in airborne particulate. C510 phosphor bronze has none of these requirements.
Do both alloys need heat treatment?
No. C172 is age-hardenable — it's typically machined or formed in a soft state then aged to develop its ~1300 MPa nominal strength and ~40 HRC hardness. C510 phosphor bronze is not precipitation-hardened; it gains strength purely through cold working, so it ships and is used in its tempered condition.
Which makes a better electrical spring contact?
C172 for high-force, high-cycle or miniaturized contacts where stress relaxation must stay low and force density is critical. C510 is the workhorse for general spring contacts and terminals where its fatigue life and conductivity are adequate and the lower cost plus easier handling win.
Is C172 worth the extra cost over C510?
Only when you need its strength. C172 costs more (4.5 vs 3.0) and adds heat-treat and handling steps. If C510's ~470 MPa nominal tensile carries the spring load with margin, C510 is the cheaper, simpler choice. Reserve C172 for parts that genuinely require its ~1300 MPa capability or non-sparking property.
Property values are typical/nominal figures for early-stage guidance only and vary by temper, grade, supplier and heat treatment. Confirm critical specifications against a certified datasheet or with an mfgiq engineer before production.