Condition Monitoring of Rolling Oils Using Automated Atmospheric Distillation

In the metalworking industry, ensuring the quality and composition of rolling oils is essential for both stable production and achieving high-quality surface finishes.

Conventional cold-rolling oil formulations used in thin-sheet manufacturing typically consist of a petroleum-derived base fluid – comprising various long-chain hydrocarbons – combined with one or more additives. These additives, such as fatty alcohols, fatty acids, and their esters, are incorporated to enhance the base oil’s oxidative stability and frictional properties. As used oils age, higher-boiling components can build up, reducing lubrication performance and potentially compromising the final product – especially in sensitive sectors like the food or pharmaceutical industry.

Atmospheric distillation analysis is a fast, reliable way to characterize rolling oils and detect compositional changes. Three typical samples used in aluminum-foil cold-rolling were examined in line with the standard ASTM D86: a base oil, a freshly rectified base oil with additives, and a heavily used base oil with additives. Using the instrument’s default distillation program, Diana 700 reproduced the manufacturer’s specifications, delivering excellent repeatability for both the base oil and the rectified rolling oil.

The heavily used oil showed a noticeable boiling delay with unstable distillation rates and temperature readings at first. However, after adjustment of the heating program, stable distillation behavior was achieved even for this challenging sample.

Distillation results for used oil revealed higher initial and final boiling points as well as increased residue levels. These findings pointed to the accumulation of higher-boiling impurities, due to thermal degradation of the rolling oil. Such boiling characteristics therefore provide a valuable insight into oil condition – and can help establish rectification intervals and reduce contamination risk.

Diana 700 enables rapid, repeatable characterization of rolling oils – allowing manufacturers to track when compositional shifts occur and to uphold consistent product quality throughout a production run. By automating key tasks (such as heat control, temperature logging, and volume measurement), this instrument offers greater safety, precision, and throughput compared to manual distillation.

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