C93500 Centrifugal Casting Bushing
C93500 Centrifugal Casting Bushing
Self-lubricating bronze bearings are engineered for applications where external lubrication is impractical. Solid lubricants are compressed and molded directly into the bearing to guarantee a maintenance-free product. No additional lubrication is necessary.
C93500 Centrifugal Casting Bushing | High Load Bearing Bronze
Introduction: Why C93500 is the Go-To for Demanding Applications
In the realm of industrial machinery, the choice of bearing material is critical to longevity and performance. C93500, also known by its SAE designation SAE 66, is a high-leaded tin bronze alloy renowned for its exceptional anti-friction properties and superior machinability. When produced via the Centrifugal Casting process, C93500 bushings inherit the alloy’s inherent advantages while achieving a new level of density, mechanical strength, and freedom from porosity.
C93500 Material Science: The Power of High Lead Content
C93500 is classified as a medium-strength leaded tin bronze. Its defining characteristic is the high percentage of lead (Pb), typically ranging from 8.0% to 10.0%. This unique chemical composition is the secret to its performance, allowing it to maintain reliable operation even when fluid lubrication temporarily fails.
The Core Advantages of C93500
The core advantages of C93500 stem from its composition. First, it offers Exceptional Anti-Seizing Properties: the high lead content is finely dispersed throughout the copper matrix, and under boundary lubrication conditions (high pressure, low speed, or poor oil film), the lead smears across the bearing surface, acting as a solid lubricant to prevent the shaft and bushing from welding together (seizing) during overheating. Second, it provides Superior Embeddability: C93500 is relatively soft, allowing it to absorb and embed small foreign particles (like dust or metal chips) that enter the bearing clearance, which protects the much more expensive and harder shaft surface from scoring and premature wear. Third, the material has excellent Conformability, allowing it to slightly deform to compensate for minor shaft misalignment or uneven load distribution, ensuring a more uniform pressure profile across the bearing surface. Finally, it boasts good Corrosion Resistance, exhibiting resilience to weak acids, mine water, and sulfite liquors found in the pulp and paper industry, making it versatile for harsh environments.
Comparative Analysis: C93500 vs. Other Bearing Bronzes
To truly appreciate C93500, it must be contrasted with other common bearing alloys. The table below highlights the trade-offs between self-lubrication, strength, and hardness.
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Alloy (UNS)
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Common Name
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Key Feature
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Lead (Pb) Content
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Hardness (HB)
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Primary Application
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C93500
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High-Leaded Tin Bronze (SAE 66)
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Superior Anti-Seizing & Embeddability
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8.0% – 10.0%
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60 – 70
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Medium load, medium speed, poor lubrication conditions
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C93200
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Bearing Bronze (SAE 660)
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General Purpose Bearing Alloy
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6.0% – 8.0%
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60 – 75
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General utility, well-lubricated applications
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C95400
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Aluminum Bronze
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Highest Strength & Hardness
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0.0%
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170 – 200
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Heavy load, low speed, high impact, requires perfect lubrication
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Contrasting Logic: While C95400 offers significantly higher strength, it is unforgiving to lubrication failure and misalignment. C93500, conversely, sacrifices some ultimate strength for “forgiveness,” making it the safer choice in applications where lubrication is inconsistent or maintenance is challenging.
The Centrifugal Casting Advantage: Density and Durability
The manufacturing method is as crucial as the material itself. Centrifugal casting involves pouring molten C93500 into a rapidly spinning mold. The centrifugal force, often exceeding 100 G’s, drives the metal against the mold wall, resulting in several key benefits:
The centrifugal casting process delivers several key benefits. The high pressure eliminates gas pockets, shrinkage, and other casting defects common in static or sand casting, leading to the Elimination of Porosity and a near-perfectly dense structure. Furthermore, the rapid cooling and directional solidification create a fine-grained, uniform structure, resulting in Superior Grain Structure that is significantly stronger and more wear-resistant. Lighter impurities and oxides are forced toward the inner diameter (ID) of the casting, allowing for their easy removal during the final machining process (Impurities Displacement). Collectively, these factors contribute to an Extended Service Life, with centrifugally cast C93500 bushings typically exhibiting a 30% or greater increase in service life compared to their sand-cast counterparts due to the enhanced density and structural integrity.
C93500 Technical Specifications (ASTM B505)
Engineers require precise data for material selection. The following table provides the standard chemical composition and minimum mechanical properties for C93500 (UNS C93500) as per ASTM B505.
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Property
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Metric Value
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Imperial Value
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Standard
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Chemical Composition
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ASTM B505
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Copper (Cu)
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83.0% – 86.0%
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Tin (Sn)
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4.3% – 6.0%
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Lead (Pb)
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8.0% – 10.0%
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Zinc (Zn)
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1.0% – 4.0%
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Mechanical Properties (Min)
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|||
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Tensile Strength
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220 MPa
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32,000 psi
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|
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Yield Strength
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110 MPa
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16,000 psi
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|
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Elongation
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15%
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15%
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|
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Brinell Hardness (HB)
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60 – 70
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60 – 70
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|
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Machinability Rating
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70
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70
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(C360 Brass = 100)
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Key Industrial Applications of C93500 Bushings
Centrifugally cast C93500 bushings are indispensable in industries where components must withstand corrosive elements, heavy loads, and inconsistent lubrication.
Centrifugally cast C93500 bushings are indispensable in industries where components must withstand corrosive elements, heavy loads, and inconsistent lubrication. In Mining and Quarry Equipment, the alloy is used in hoist drums, conveyor rollers, and heavy-duty pivot points, where its resistance to acidic mine water and its ability to handle abrasive particles make it ideal for this harsh environment. For Pulp and Paper Machinery, its resistance to chemical attack from sulfite liquors and other paper-making chemicals ensures long life in wet-end and drying sections of paper machines. The Petrochemical and Pump Industry utilizes C93500 for pump bushings, valve guides, and wear rings that handle non-oxidizing acids and petroleum products. Finally, in General Industrial Machinery, it is found in printing presses (for vibration dampening and smooth operation) and machine tools where precision and reliability are paramount.
Customization and Bushing Types
C93500 is not a one-size-fits-all solution. We offer precision machining to create various bushing types tailored to specific load and lubrication requirements:
We offer precision machining to create various bushing types tailored to specific load and lubrication requirements. Straight Sleeve Bushings are the most common form, designed primarily to handle radial loads (perpendicular to the shaft). Flanged Bushings incorporate a flange to handle both radial and axial (thrust) loads, often used for positioning and eliminating the need for separate thrust washers. Grooved Bushings are essential for poor lubrication environments, featuring internal oil grooves (e.g., figure-eight, circular, or straight) machined to ensure lubricant is evenly distributed across the bearing surface, dissipating heat and extending life. Lastly, Split Bushings are manufactured in two halves for easy installation and replacement on large shafts or equipment where the shaft ends cannot be disassembled.
Conclusion: Invest in Forgiveness and Durability
The C93500 centrifugal casting bushing offers a unique blend of high lead content for self-lubrication and the structural integrity of centrifugal casting. It is the optimal, cost-effective solution for medium-load applications where the risk of lubrication failure, minor misalignment, or corrosive exposure is present.
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