C93400 Leaded Bronze Bearing: High-Performance American Standard Cast Copper Alloy

C93400 Leaded Tin Bronze is a premier copper-based alloy engineered to meet rigorous American Standards (ASTM). Specifically governed by ASTM B505 (Continuous Cast) and ASTM B271 (Centrifugal Cast), this alloy is optimized for high-friction environments where durability and anti-seizing properties are paramount.

As a high-leaded tin bronze, C93400 balances the structural strength of tin with the superior dry-running capabilities of lead, making it an essential material for heavy-duty industrial bearings and bushings.

1. Chemical Composition (ASTM Compliance)

The performance of C93400 is defined by its precise metallurgical balance. The inclusion of lead (Pb) provides a natural lubricant film, while tin (Sn) ensures the matrix remains strong enough to handle significant mechanical loads.

2. Technical Parameters & Mechanical Properties

C93400 is selected for its stable mechanical performance under varying industrial temperatures and pressures. Below are the typical values achieved through continuous casting (ASTM B505):

• Tensile Strength (Min): 30,000 psi (207 MPa)

• Yield Strength (0.5% Extension): 16,000 psi (110 MPa)

• Elongation (in 2 inches): 10%

• Brinell Hardness (500 kg load): 55 – 65 HB

• Density: 0.322 lb/in³ (8.91 g/cm³)

• Thermal Conductivity: 30.2 BTU/ft²/ft/hr/°F at 68°F

• Machinability Rating: 70 (Ease of precision finishing)

3. Core Material Features

Exceptional Lead-Infused Lubricity

The high lead concentration in C93400 is designed for “emergency running” scenarios. If the primary oil or grease lubrication fails, the lead within the copper matrix smears across the surface, preventing metal-on-metal contact and protecting the mating shaft from galling or seizing.

High Corrosion and Wear Resistance

Thanks to the tin content, this alloy develops a protective oxide layer that resists corrosion in aggressive environments, including salt water, brine, and dilute acids. It is highly effective in preventing surface erosion and pitting in fluid-handling equipment.

Superior Conformability and Embeddability

C93400 is a “forgiving” material. It can conform to minor misalignments in industrial machinery and allows small abrasive particles to embed into the bronze surface, preventing them from scratching the more expensive steel shafts.

4. Key Industrial Application Fields

C93400 tin-lead bronze bearings are widely utilized across industrial sectors that demand high reliability and low maintenance.

• Marine Engineering: Utilized for seawater pump components, propeller shaft sleeves, and marine hardware due to its resilience against salt-water corrosion.

• Chemical & Petroleum Industry: Ideal for fabricating corrosion-resistant valves, pipe fittings, pump bodies, and seals exposed to chemical reagents.

• General Machinery Manufacturing: Used for heavy-load bearings, gears, cams, and wear plates in industrial gearboxes and hydraulic systems.

• Food Processing Equipment: Applied in mixers, stirring rods, and processing knives where lubrication and hygiene-compliant corrosion resistance are required.

• Tooling & Precision Instruments: Serves as guide bushings and sliding elements in CNC machining centers, textile looms, and metallurgical equipment.

5. Selection Guide: ASTM B505 vs. ASTM B271

When ordering C93400 copper alloy, the casting method impacts the final performance:

1. ASTM B505 (Continuous Cast): Best for uniform grain structure and high-volume production of rods and tubes. It offers excellent internal soundness.

2. ASTM B271 (Centrifugal Cast): Ideal for large-diameter rings and bushings. The centrifugal force during casting results in a denser material with superior mechanical properties for circular parts.

6. Frequently Asked Questions (FAQ)

Q: How does C93400 compare to standard C93200 (SAE 660)?
A: While both are leaded tin bronzes, C93400 typically features a tighter range for tin and lead, often providing slightly enhanced corrosion resistance and lubricating properties for more specialized industrial applications.

Q: Can C93400 operate without external lubrication?
A: It has excellent self-lubricating qualities for short periods or low-speed applications. However, for continuous heavy-load operations, regular lubrication is recommended to maximize the bearing life.

Q: What is the recommended mating material for C93400 bearings?
A: It is most effective when paired with hardened steel shafts (minimum 300-400 HB) to ensure minimal wear on the rotating components.

For detailed technical datasheets or custom casting quotes for C93400 Leaded Bronze, please contact our engineering team.