المجلة الدولية للعلوم والتقنية

This practical study carried out to find the best percentage of cooling fluid components in turning of medium carbon steel type (C45). The study accomplished in Applied Researches & Development Center (Tripoli – Libya). The study based upon preparing of cooling fluids form three types of mine oils (Twain from Libyan production & the third from K.S.A production), where three mixes from each type prepared and each mix used in turning workpiece sample from medium carbon steel (C45), by fixing all affecting factors of cutting process which influencing the surface roughness of the workpiece (Depth of cut – Rotating speed – Feeding rate – Discharge of cooling fluid), then surface roughness measured for each case as an indication for the efficiency degree of each type of cooling fluid. In order to support the results obtained, the imported cooling fluid (Canadian made), was used as reference for comparing the efficiency of the locally prepared cooling fluids. The results obtained from the study showed that the best mixing ratio for all types of oil used was (1:20), also one type from these mixes proved to be more efficient than the imported cooling fluid. The results of the study encouraged to give some recommendations achieving improve for technical & economic aspects in the process of using locally prepared cooling fluids. الكلمات المفتاحية: