Bushings for Conveyor & Roller Tables: Winning in Heat, Water, and Scale
In conveyor and roller table systems—especially in steel mills—the toughest enemy isn’t peak load. It’s the environment: extreme radiant heat from red-hot steel, repeated water-spray impact that washes away grease, and constant invasion of iron oxide scale.
That combination quickly turns “standard” bushing solutions into chronic downtime. The right self-lubricating bushing design, however, can deliver long service life with minimal or even zero maintenance.
1) Conveyor & Roller Tables – Entry & Exit Roller Tables
Roller tables are among the most numerous assets in a rolling mill. They operate close to or in contact with hot material, so ambient temperature is consistently high.
Recommended bushing type
- Graphite-plugged self-lubricating bronze bushings (JDB series)
- Typically flange bushings for easy locating and to take light axial loads
Recommended material system
- Tin bronze base + graphite plugs, e.g. C93200 (SAE 660) or ZCuSn5Pb5Zn5
Why this works (key technical points)
- High-temperature stability
Tin-bronze self-lubricating bushings remain physically stable around 250–300°C. Unlike conventional grease, the solid lubricant does not carbonize and fail in hot zones. - Water-spray resistance (no lubricant washout)
Entry/exit roller tables see heavy cooling water. Graphite is a solid lubricant and won’t be washed away, while tin bronze provides strong corrosion resistance in wet service. - Contamination tolerance (scale embedability)
Fine oxide scale is unavoidable. Tin bronze is relatively softer than shafts and can allow micro-particles to embed in the bushing surface, protecting expensive roller shafts from scoring.
2) Conveyor & Roller Tables – Looper Towers / Looper Arms
Loopers regulate strip tension between stands. The motion is typically frequent oscillation with high responsiveness requirements—so low friction and anti-stick-slip behavior matter more than extreme load capacity.
Recommended bushing type
- Self-lubricating composite bearings (thin-wall) or thin-wall graphite-plugged bushings
Recommended material system
- Steel-backed composite (e.g., steel + bronze powder + PTFE or POM)
(Often described as PTFE composite bushings or POM composite bronze bushings) - Alternative where appropriate: high-strength brass base self-lubricating bushings
Why this works (key technical points)
- Ultra-low friction for fast response
PTFE films or graphite lubrication can deliver very low starting friction (μ ≈ 0.03–0.10), reducing risk of stick-slip (“creep”) and improving control sensitivity. - High fatigue life under oscillation
Loopers operate continuously in reciprocating motion. Composite systems are designed to handle repeated micro-sliding and oscillation with stable wear behavior. - Compact design (thin-wall advantage)
Looper mechanisms are space-constrained. Steel-backed composite bushings offer high structural stiffness with reduced wall thickness—supporting lighter, more compact designs.
3) Conveyor & Roller Tables – Walking Beam Cooling Beds
Cooling beds sit after roller tables and move product laterally for cooling. Mechanisms are often long-link structures with low-speed, heavy-duty reciprocating motion and widespread bearing points.
Recommended bushing type
- Large-size solid-lubricated bushings and/or thrust washers
Recommended material system
- High tensile brass, e.g. C86300, with embedded solid lubricant
Why this works (key technical points)
- Maintenance-free operation at scale
Cooling beds may have hundreds or thousands of lubrication points—manual greasing is difficult to execute consistently. Solid-lubricated bushings can enable multi-year, maintenance-free operation. - Dust/oxide powder resistance
Oxide dust is abundant as the steel cools. Solid lubricant films can help isolate the sliding interface and reduce sensitivity to dust ingress.
Quick Reference: Application Selection Table
| Area | Load & Motion | Environment | Core material requirement | Recommended solution |
|---|---|---|---|---|
| Entry & Exit Roller Tables | Medium load, high-speed rotation | High heat (200°C+), water spray | Heat resistance, corrosion resistance, self-lubrication | Tin bronze + graphite plugs (JDB), often flanged |
| Looper Towers / Arms | Low load, high-frequency oscillation | Ambient, high sensitivity | Low friction, fatigue resistance, compact structure | Steel-backed composite (ptfe/pom composite bronze bushing-type), thin-wall options |
| Cooling Bed Linkages | High load, very low-speed reciprocation | Heavy dust/scale, difficult maintenance | Long life, robustness, minimal maintenance | High tensile brass + solid lubricant (e.g., C86300), plus thrust washers |
Key Messages to Emphasize
- Maintenance-free operation for large-scale cooling bed systems.
- High-temperature resistant bronze bushings for heat treatment zones and exit rollers.
- Solving lubrication washout in water-spray environments.
If you share your operating temperature range, shaft material, and typical speed/load per station, this can be refined into a concise bushing specification (material + style + clearances) for each position.
