CuZn33Pb2Si-C Brass Bushing Overview

CuZn33Pb2Si-C, also known as CC751S, is a leaded brass alloy specifically designed for casting applications. It is widely utilized in the production of brass bushings due to its excellent machinability, good mechanical properties, and durability, making it suitable for demanding engineering environments.

Chemical Composition

The typical chemical composition of CuZn33Pb2Si-C includes the following elements:

• Copper (Cu): 63.0% – 66.0%
• Zinc (Zn): 30.0% – 32.0%
• Lead (Pb): 1.5% – 2.5%
• Silicon (Si): 0.5% – 1.0%
• Other Elements: Trace amounts of iron, nickel, and aluminum may be present.

Mechanical Properties

The mechanical properties of CuZn33Pb2Si-C in its as-cast state are as follows:

• Tensile Strength (σb): ~300 MPa
• Yield Strength (σs): ~160 MPa
• Elongation: ~20%

These characteristics demonstrate a balance of strength, ductility, and wear resistance, making the alloy suitable for components subject to mechanical stress.

Applications of CuZn33Pb2Si-C Brass Bushings

1. Bushings: The alloy’s excellent machinability and wear resistance make it an ideal choice for brass bushings, commonly used in industrial machinery to reduce friction and enhance performance.
2. Fittings: Corrosion-resistant properties make it a reliable material for plumbing and HVAC systems.
3. Gears and Valves: Provides mechanical stability and durability under stress, ensuring long-term performance in demanding applications.

Advantages of CuZn33Pb2Si-C for Brass Bushings

• Machinability: Lead content enhances machinability, allowing for efficient shaping and precision.
• Wear Resistance: High resistance to wear extends the lifespan of bushings and reduces maintenance costs.
• Corrosion Resistance: Suitable for harsh environments due to its ability to withstand corrosive conditions.

Summary

CuZn33Pb2Si-C is an exceptional material for brass bushings and similar components requiring strength, corrosion resistance, and excellent machinability. Its balanced mechanical and chemical properties make it a preferred choice for applications across industries, including machinery, plumbing, and automotive engineering.

CuZn33Pb2Si-C Brass Bushing With Graphite

CuZn33Pb2Si-C brass bushings, enhanced with embedded graphite, provide a self-lubricating solution that improves performance across a range of demanding applications. This combination harnesses the mechanical strength and durability of the brass alloy with the inherent lubricating properties of graphite, creating a low-maintenance and efficient product.

Properties of Graphite-Embedded CuZn33Pb2Si-C Brass Bushings

Chemical Composition

• Base Material: CuZn33Pb2Si-C (CC751S), comprising copper, zinc, lead, and silicon.
• Graphite: Embedded within the bushing structure, serving as a solid lubricant.

Mechanical Properties

• Tensile Strength: ~300 MPa
• Yield Strength: ~160 MPa
• Elongation: ~20%
• Coefficient of Friction: Typically ranges from 0.10 to 0.15, reflecting reduced friction due to graphite.

Advantages of Graphite-Embedded CuZn33Pb2Si-C Bushings

• Self-Lubricating: The graphite inclusion minimizes or eliminates the need for external lubrication, ideal for environments where traditional lubricants are impractical.
• Improved Wear Resistance: Graphite creates a protective low-friction film on contact surfaces, reducing wear and extending component life.
• Corrosion Resistance: The brass alloy resists corrosion, with graphite further reducing wear-related vulnerabilities.
• High Load Capacity: Designed to handle heavy mechanical loads, making them suitable for rigorous operations.

Applications

• Automotive Industry: Used in bearings and bushings to reduce friction and improve durability in high-performance systems.
• Heavy Machinery: Perfect for construction, mining, and industrial equipment requiring robust, wear-resistant components.
• Marine Applications: Excellent for marine environments, offering corrosion resistance and self-lubrication under harsh conditions.

Graphite-embedded CuZn33Pb2Si-C brass bushings are a reliable and efficient choice for industries requiring robust, low-maintenance, and high-performing solutions.

Compare CuZn33Pb2Si-C (CC751S) with CuZn34Mn3Al2Fe1-C (CC764S) brass in terms of load capacity, wear resistance, and bushing suitability.

Both CuZn33Pb2Si-C (CC751S) and CuZn34Mn3Al2Fe1-C (CC764S) are European standard (EN 1982) special brass casting alloys. However, their microstructural chemistry leads to distinct mechanical profiles: CC751S is a leaded silicon brass, while CC764S is a manganese bronze (high-tensile brass).

1. Property Comparison

2. Load Capacity

• CuZn34Mn3Al2Fe1-C (CC764S): Superior static and dynamic load capacity. Due to the addition of Aluminum (Al) and Iron (Fe), CC764S develops a dense, high-strength matrix capable of supporting continuous heavy loads, heavy shocks, and high unit pressures without plastic deformation.

• CuZn33Pb2Si-C (CC751S): Moderate-to-high dynamic load capacity. While silicon adds strength compared to plain brass, the presence of lead (0.8–2.2%) slightly reduces the ultimate tensile and impact toughness relative to high-tensile brasses.

3. Wear Resistance & Friction Behavior

• CC751S (Silicon-Leaded): Excellent against adhesive wear under moderate loads. Silicon (Si) forms hard silicide phases within the matrix that resist surface scuffing. Meanwhile, Lead (Pb) provides soft lubricating pockets that lower the coefficient of friction and protect matching shaft surfaces during boundary lubrication or unexpected oil starvation.

• CC764S (Manganese Bronze): High resistance to abrasive wear under extreme load conditions. Hard manganese-iron intermetallic particles disperse throughout the matrix to prevent premature mechanical wear under high-pressure sliding. However, without soft free-machining additives, it requires a continuous oil film or graphite lubrication to prevent galling against unhardened steel shafts.

4. Bushing Suitability & Selection Matrix

Choose CuZn33Pb2Si-C (CC751S) for:

1. Precision Machined Bushings: Where complex internal oil grooves, tight tolerances, and superior surface finishes are required cost-effectively.

2. Intermittent / Marginal Lubrication: Bushings in systems prone to brief oil starvation or oscillating startup conditions where lead provides self-lubricating fallback.

3. Dezincification & Aqueous Environments: Systems exposed to water or mild chemicals benefit from silicon's resistance to dezincification.

4. Typical Uses: Automotive transmission bushes, rocker arms, hydraulic pump shoe guides, general-purpose sleeve bearings.

Choose CuZn34Mn3Al2Fe1-C (CC764S) for:

1. Extreme Impact & Heavy Load Bushings: Applications operating under severe shock loads or high static compressive forces where high tensile strength ≥600 MPa prevents bush wall crushing.

2. Solid Lubricant Base Matrix: Widely used as the base metal casting for graphite-plugged self-lubricating bushings, where heavy load capacity is provided by the brass matrix and lubrication is provided by embedded graphite plugs.

3. Typical Uses: Earthmoving equipment main joints, hydraulic excavator toggle bushings, crane pivot bearings, die-set guide bushings.