When 100-ton presses need bushings that won’t gall or marine prop shafts demand zero corrosion, C91700 Nickel Tin Bronze steps up. This copper-tin-nickel alloy (88% Cu, 8% Sn, 4% Ni) carries extreme loads while shrugging off salt spray. RoHS-exempt per Annex III 6c – it’s the backbone of crusher bearings, warship components, and steel mill gears.
TECH SPECS: ENGINEERED FOR BRUTAL CONDITIONS
(ASTM B271 / UNS C91700 / RoHS Annex III Exempt)
| Property | C91700 | C93200 (SAE 660) | Aluminum Bronze |
|---|
| Composition | 88% Cu, 8% Sn, 4% Ni | 83% Cu, 7% Sn, 7% Pb | 81% Cu, 11% Al, 4% Fe |
| Compressive Strength | 510 MPa | 330 MPa | 550 MPa |
| Fatigue Strength | 165 MPa | 120 MPa | 240 MPa |
| Corrosion Rate | 0.003 mm/yr (Seawater) | 0.08 mm/yr | 0.001 mm/yr |
| Max PV Value | 50.000 psi·ft/min | 28.000 | 45.000 |
| Thermal Conductivity | 40 W/m·K | 45 W/m·K | 59 W/m·K |
Certifications: ASTM B271. ASME SB271. ABS Marine, Lloyds Register, RoHS Annex III 6c Exempt
5 REASONS ENGINEERS SPECIFY C91700
Crush-Proof Bearing Surfaces
"Handles 10X higher loads than leaded bronze – survives 200 MPa stress in ore crusher sleeves."
Saltwater Immunity
"0% dezincification after 15+ years in tidal zones – US Navy-approved for submarine shaft sleeves."
Heat Resistance
"Maintains strength at 260°C – outperforms C93200 in steel mill conveyor bearings."
Anti-Gall Shield
"Nickel-tin matrix prevents adhesive wear against hardened steel shafts (μ=0.15)."
Lifetime Value
"Lasts 5X longer than leaded bronze in mining equipment – slashes downtime costs by 60%."
KEY FEATURES: BEYOND THE DATA SHEET
Embedded Hardness: Nickel-tin precipitates (HV 350) resist embedment of abrasive particles
Vibration Damping: Absorbs harmonic shocks in high-RPM turbine bearings
Non-Sparking: Safe for coal handling plants and explosive environments (MSHA certified)
Chip Control: Machines cleanly at 120 SFM with carbide tools – no stringy chips
PRECISION PROCESSING: FROM INGOT TO INSTALLATION
1 Controlled Alloying
"Vacuum-induction melted Cu-Sn base with 4% Ni addition – eliminates porosity for uniform structure."
2 Centrifugal Casting
"Spun at 1.200 RPM into dense, void-free bushings/sleeves (±0.5% dimensional tolerance)."
3 Heat Treatment
"Stress-relieved at 290°C to optimize hardness (BHN 170) without brittleness."
4 Machining Finish
"CNC-turned to Ra 0.8μm surface finish – ready for press-fit installation."
WHERE IT DOMINATES: CRITICAL APPLICATIONS
| Industry | High-Stress Components | Why C91700? |
|---|
| Marine | Propeller shafts, rudder bearings | Immune to saltwater pitting & cavitation |
| Mining | Crusher eccentric bushings | Withstands 200-ton impact loads |
| Power Gen | Turbine thrust washers | Handles 10.000 RPM steam erosion |
| Steel Mills | Rolling mill gear sleeves | Resists scale embedment at 400°C |
| Construction | Crane sheave bushings | No galling under shock loads |
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