Bronze Embedded Solid Lubricant Bearing: 6-6-3 Bronze + Graphite/MoS₂ — Application Matrix & Material Selection

The bronze embedded solid lubricant bearing uses 6-6-3 bronze (CuSn6Zn6Pb3) as the matrix with graphite and molybdenum disulfide (MoS₂) solid lubricant plugs embedded in a regular pattern. Thanks to the higher density of 6-6-3 bronze versus high-strength brass, it delivers excellent wear resistance under high-temperature, low-load and medium-speed conditions. It is proven in fireplace doors, baking/heat-treat furnace rollers, rubber machinery, light-industry machinery and the machine-tool industry.

1. Product Definition & Material Breakdown

This product belongs to the embedded (oilless / solid-lubricant) self-lubricating bearing family. Arrays of solid-lubricant plugs (graphite + MoS₂ composite) are drilled or pressed into the sliding surface of a high-strength wear-resistant bronze matrix. During operation the lubricant is released in tiny amounts and forms a self-renewing solid film on the friction surface — no grease, no leakage, maintenance-free.

• Matrix: 6-6-3 bronze CuSn6Zn6Pb3 — tin-zinc-lead bronze with high density and good anti-friction behavior, dimensionally stable at elevated temperature;
• Solid lubricant: graphite + MoS₂ composite — graphite lubricates well and conducts heat in humid air; MoS₂ gives low friction when dry/vacuum. The composite keeps the bearing stable across a wide range of conditions, which is why the friction band is relatively broad (μ 0.04–0.15);
• Process: cast/machined matrix + press-fitted lubricant plugs, supplied as bushings, half-bearings, guide plates or thrust washers.

2. Why 6-6-3 Bronze, Not High-Strength Brass

For embedded solid-lubricant bearings the matrix is usually chosen between high-strength brass (e.g. CuZn25Al5Fe3Mn3) and 6-6-3 bronze. The deciding factor is density and wear behavior at high temperature with low load:

Selection conclusion: When the duty is “high temperature + low load + medium speed + hard-to-lubricate / oil-free”, the 6-6-3 bronze embedded bearing is the better choice. For primarily heavy-load duties, switch to a high-strength brass matrix.

3. Technical Parameters

4. Application Matrix (Industry × Duty × Reason)

The matrix below summarizes typical deployments. The common thread is low load, high temperature, medium speed, maintenance-free / oil-free:

Matrix rule: If a duty meets two or more of — temperature ≥150℃, load ≤60 N/mm², speed ≤2 m/s, oil-free/hard-to-lubricate — evaluate the 6-6-3 bronze embedded bearing first.

5. Material Selection Guide

Three-step selection:

1. Temperature: duty ≥150℃ with long stable running → choose 6-6-3 bronze embedded (stable to 350℃);
2. Load: dynamic load ≤60 N/mm² uses this product; far above → use high-strength brass matrix;
3. Speed & environment: sliding speed ≤2 m/s and oil-free / hard-to-maintain / dusty → embedded solid lubricant is optimal; higher speed (>2 m/s) needs PV re-check or alternative design.

6. Installation & Service Notes

• PV boundary: treat 60 N/mm² and 2 m/s as limits; avoid sustained overload;
• Fit: moderate interference — too tight blocks the film, too loose causes vibration;
• Mounting: never hammer the ring; press in evenly with proper tooling;
• Running-in: slight dark lubricant powder at start is normal and reduces after run-in;
• Maintenance: though “maintenance-free”, inspect wear periodically and replace when limits are exceeded.