The Challenge: Why Chains Fail at High Temperature
A roller chain consists of precision components — pins, bushings, rollers, and link plates — that rely on a lubricating film to prevent metal-to-metal contact, especially in the critical pin-bushing interface. At room temperature, standard mineral oil chain lubricants perform adequately. At elevated temperatures, the degradation accelerates exponentially. The dominant failure mechanisms are: evaporation of light oil fractions, oxidative polymerization into sticky residues, thermal cracking of the hydrocarbon backbone, loss of additive effectiveness, and carbonization — where the oil thermally decomposes into hard carbon particles that accelerate abrasive wear.
Temperature Ranges and Suitable Lubricant Types
| Temperature Range | Lubricant Type | Base Oil | KLÜBER Product |
| Up to 120°C | Mineral or PAO chain oil | Mineral / PAO | Klubersynth LI 44-22 |
| 120-180°C | Ester or PAO synthetic chain oil | Ester / PAO | Klubersynth LI 44-42 |
| 180-220°C | Bentonite or PTFE-thickened synthetic | Silicone / Ester | Kluberlub BE 71-501 |
| 220-260°C | PFPE/PTFE grease | PFPE | Barrierta L 55/2 |
| Above 260°C | Solid film / dry lubricant | Graphite, MoS₂, BN | Wolfrakote TOP (paste, 1100°C dry film) |
> Tip
For oven chains operating at 180-220°C, reduce the lubricant application quantity but increase the frequency. Applying too much lubricant at once leads to dripping and carbonization in the oven. A small amount applied more frequently maintains a thin, effective film without excess residue. Automatic metered application systems are strongly recommended for consistent results.
Application Methods for High-Temperature Chains
Automatic Drip or Spray Systems
For continuous oven chains, an automatic applicator delivers a metered drop or short spray of lubricant directly to the pin-bushing interface at timed intervals. This provides consistent lubrication without over-application. The system should be adjustable for chain speed and oven temperature.
Brush Application
Brush application is suitable for chains accessible during operation. The brush deposits a thin, even film on the link plates and pins. Use brushes with natural bristles (synthetic bristles may melt at high temperatures) and replace them regularly as they wear.
Centralized Lubrication
For complex conveyor systems with multiple lubrication points in hard-to-reach locations, centralized lubrication systems distribute lubricant from a single reservoir to each point through metering valves. This ensures no lubrication point is missed and is the standard approach for large paint shop and powder coating conveyors.
Frequently Asked Questions
Q: Can I use a standard chain oil at higher temperatures by applying it more often?
No. Increasing the application frequency of a standard chain oil at temperatures above its capability does not solve the fundamental problem — the oil thermally degrades almost immediately upon contacting the hot chain. The degraded residue builds up faster than it can be replenished, forming carbonaceous deposits that increase friction and wear. You must use a lubricant rated for the actual chain operating temperature.
Q: What causes chain elongation at high temperatures?
Chain elongation (stretch) at high temperatures has two components: mechanical wear in the pin-bushing interface (which lubrication addresses) and thermal expansion (which it does not). A steel chain expands approximately 0.012 mm per meter per degree Celsius. A 30-meter chain at 200°C is approximately 65 mm longer than at 20°C — this is normal thermal expansion, not wear. Regular measurement of chain pitch elongation distinguishes thermal effects from irreversible wear elongation.
Q: Why is PFPE/PTFE so effective at extreme temperatures?
PFPE (perfluoropolyether) is a completely fluorinated synthetic oil — the carbon-fluorine bond is one of the strongest in organic chemistry (485 kJ/mol vs 413 kJ/mol for C-H). This makes PFPE essentially immune to thermal degradation and oxidation. PTFE (polytetrafluoroethylene) thickener is similarly stable. Together, they form a lubricant that maintains its viscosity and lubricity at temperatures where hydrocarbon-based lubricants have long since carbonized. The trade-off is cost — PFPE/PTFE greases are 20-50× more expensive than mineral oil greases, but for critical high-temperature applications, they are the only reliable choice.