C932 Bronze vs C630 Nickel-Aluminum Bronze
C932 (SAE 660) bearing bronze and C630 nickel-aluminum bronze are both copper alloys for bearings and pumps, but they serve different duty levels. C932 is a leaded tin bronze tuned for low-friction sleeve bearings and bushings at moderate loads. C630 is a high-strength nickel-aluminum bronze for marine propellers, pump components and heavily loaded parts that also see seawater.
The verdict
Choose C932 bearing bronze for plain bushings and sleeve bearings where embeddability, conformability and low friction at moderate load matter most. Choose C630 nickel-aluminum bronze when the part must carry high load (~620 MPa nominal tensile) and resist seawater erosion and cavitation — propellers, valve stems and pump wear rings.
Side-by-side data
| Property | C932 Bronze | C630 Nickel-Aluminum Bronze |
|---|---|---|
| Category | Copper Alloy | Copper Alloy |
| Density (g/cm³) | 8.8 | 7.58 |
| Tensile strength (MPa) | 310 | 620 |
| Yield strength (MPa) | 150 | 310 |
| Elongation (%) | 20 | 15 |
| Hardness | 65 HB | 170 HB |
| Max service temp (°C) | 250 | 300 |
| Machinability | ●●●●● | ●●●●● |
| Corrosion resistance | ●●●●● | ●●●●● |
| Relative cost | ●●●●● | ●●●●● |
| Thermal cond. (W/m·K) | 59 | 42 |
| Typically used for | Bearings & bushings (low friction) | Marine propellers & pump parts |
Which should you choose?
Choose C932 Bronze when…
- You need a forgiving plain bearing or bushing with good conformability and embeddability
- Loads and speeds are moderate and a low-friction tin-bronze surface is the priority
- The bearing runs against a hardened steel shaft and should be the sacrificial part
- Machinability (3.5 vs C630's 2.5) helps make finished bushings economically
- The part is cast to near-net shape as a sleeve, thrust washer or bearing blank
- Service temperature stays modest (≤250°C nominal) and load is steady
Choose C630 Nickel-Aluminum Bronze when…
- The part carries high mechanical load — ~620 MPa tensile and 170 HB nominal, double C932's strength
- It operates in seawater and must resist corrosion, erosion and cavitation (corrosion 4.5)
- You're making propellers, pump impellers, wear rings or valve components
- Higher max-temp capability (~300°C nominal) is needed
- Strength-to-weight helps — C630's 7.58 g/cm³ is lighter than C932's 8.8
- The part must withstand both structural stress and a marine environment at once
Key differences that matter
- C630 is far stronger: ~620 MPa tensile and 170 HB nominal versus C932's ~310 MPa and 65 HB.
- C932 is the classic bearing bronze — leaded tin bronze chosen for low friction, conformability and embeddability, not raw strength.
- C630 resists seawater corrosion, erosion and cavitation better (4.5 vs 4.0), making it the marine-propeller and pump standard.
- C932 machines more easily (3.5 vs 2.5), which matters for finishing precision bushings.
- C630 is notably lighter at 7.58 g/cm³ versus C932's 8.8, aiding rotating marine parts.
- C630 handles higher temperatures (~300°C vs 250°C nominal) and higher contact stress.
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Open the Material SelectorGet a Quote →Frequently asked questions
Can C630 be used as a bearing like C932?
It can run as a high-load bearing or wear ring, but it lacks C932's embeddability and conformability — the ability to absorb debris and tolerate misalignment. C630 is harder and stronger, suited to heavily loaded or seawater wear parts, while C932 remains the better forgiving plain-bearing material against a steel shaft.
Why is nickel-aluminum bronze preferred for marine propellers?
C630 combines high strength (~620 MPa nominal), good ductility, and strong resistance to seawater corrosion, erosion and cavitation (corrosion 4.5). Propellers see high cyclic load plus an aggressive saltwater environment, and NAB handles both at once — which is why it's a long-standing propeller and pump-component standard.
Does C932 contain lead?
Yes — C932 (SAE 660) is a leaded tin bronze; the lead aids machinability and bearing performance. That matters for potable-water or food-contact parts subject to lead-content regulations, where a low-lead or lead-free alternative may be required. C630 nickel-aluminum bronze is lead-free but is a structural/marine alloy, not a drop-in bearing replacement.
Which is easier to machine?
C932, rated 3.5 versus C630's 2.5. The leaded tin bronze cuts more freely and produces good bearing surfaces with standard tooling. C630's higher strength and hardness make it tougher to machine, so finished NAB parts cost more to produce — a trade-off for its load and corrosion capability.
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.