If continuous casting mould slag has been the subject of many studies, this is not true for lubricating oils. Actually, there is a significant potential for progress through formulating these lubricants in order to make the industrial process more reliable and to improve both the operating conditions and the product quality. Specific laboratory tests have been carried out in order to understand the oil behaviour at high temperature. The lubrication mechanism has been further studied with the help of high-speed visualization of the phenomena occurring at the meniscus level during the industrial continuous casting of bar products. The results make it possible to better understand the mechanisms of oil lubrication and to precise the mechanisms of the formation of the first solidified steel shell along with the formation of solidification marks and solidification hooks. This should open the way for the development of new lubricants.