Lubrication Management Expert

Cold starts can be challenging for industrial and mining equipment in winter. Poor oil flow at low temperatures can delay lubrication, increase friction and accelerate wear. Two basic indicators used to evaluate low-temperature performance are pour point and solidification point.

Both describe how lubricating oil behaves as temperature decreases. In general, a lower value indicates better low-temperature flowability, but neither parameter should be considered on its own when selecting oil for an industrial lubrication system.

Solidification Point

The solidification point is the temperature at which an oil sample stops moving under specified test conditions, measured in °C. According to GB/T 510-2018, the sample is gradually cooled and repeatedly observed. When the oil surface stops moving, while movement resumes after the temperature is raised by 2°C, the corresponding temperature is determined as the solidification point.

It indicates the temperature at which the oil loses its ability to flow under the specified test conditions. However, it should not simply be interpreted as the temperature at which the entire oil becomes solid.

Pour Point

The pour point is the lowest temperature at which an oil sample can still flow under specified cooling conditions. The test method is specified in GB/T 3535-2025.

For the same oil, the pour point is typically around 2–3°C higher than the solidification point, although the difference can vary. Pour point is generally more useful when considering lubricant performance in cold environments.

However, pour point is not the same as the actual minimum pumping or operating temperature. Pump type, oil viscosity, piping, reservoir design and system conditions can all affect cold-start performance.

What Does This Mean for Industrial Lubrication?

For cold-weather applications, lubricant selection should consider pour point together with viscosity, viscosity index, low-temperature viscosity and actual operating conditions.

For equipment already in service, low-temperature performance is only one part of oil condition. Monitoring viscosity, water content, particle contamination and other oil condition indicators can help identify lubricant deterioration and potential lubrication problems.

At AITAI, oil purification and condition monitoring work together to support reliable industrial lubrication. Understanding oil properties and monitoring their changes can help maintain cleaner oil, more stable lubrication and more reliable equipment operation.