AbstractA semi‐synthetic meta‐stable oil system for cold rolling of steel was developed as a substitute for a mineral oil based ‘stable emulsion’‐type soluble oil. The developed oil system, comprising a ‘coating oil’ for post‐pickling application and a ‘rolling oil’ for the rolling operation, was tested in the laboratory and subsequently subjected to extensive field trials in an integrated steel plant. Use of the developed oil system resulted in 25–50 per cent lower roll loads and 30–50 per cent reduction of inter‐stand tensions compared with the mineral oil‐based ‘stable emulsion’. It was also possible to increase the ‘strip reduction ratio’ and input coil width with the use of the newly‐developed oil. Overall performance of the new semi‐synthetic oil was found to be far superior to that of