Formulation of sub-zero metalworking fluids for cutting processes: Influence of additives

Sub-zero metalworking fluids (MWF) are supplied to the machining process at temperatures below 0 °C, but above those used in cryogenic machining. As sub-zero MWF are liquids, such that additives can be used. The effects of such additives on machining with sub-zero MWF were studied in the present work. The base MWF was a mixture of water and ethane-1,2-diol with which temperatures down to about −50 °C can be achieved. The influence of the properties of the base MWF, which can be influenced by the concentration of the ethane-1,2-diol, on the machining process are discussed. Anti-corrosion, anti-wear, and extreme pressures additives were examined by face turning of steel for varied temperatures of the sub-zero MWF regarding tool temperatures, tool wear, and surface roughness. The effects achieved by the additives were found to be temperature-dependent and interactions between the additives were observed. The results show that further research on the effects of additives in sub-zero MWF is needed.