USE OF QUANTITATIVE INFRARED SPECTROMETRY IN ROLLING-OIL AND ANALYTICAL-CHEMISTRY

Rolling oils made for modern cold-rolling processes have to meet high requirements. They are of crucial importance both for the process and for the surface finish of the rolled sheets. In order to achieve optim um results from either viewpoint, the development of fast and simple a nalytical techniques is desirable. They should ensure the most continu ous control possible of the cooling lubricants. The present article fe atures a new technique that meets such requirements. The composition o f modern cold-rolling oils is extraordinarily complex. The rolling oil constituents, on the one hand, cover a very large polarity range, whi le on the other hand their concentrations in the rolling oil strongly differ. Furthermore, the specimens to be analysed are generally emulsi ons containing over 95% water in a relatively inhomogeneous distributi on. This all adds up to the fact that the chemical analysis of cooling lubricants by use of special equipment mostly requires very time- and work-intensive specimen preparation. A new technique has been develop ed whereby, with the aid of chemometric methods, quantitative data are inferred from infrared spectra of rolling oils or rolling oil emulsio ns regarding their composition. Two important parameters - the oil con centration of the rolling oil emulsion and the saponification value (S v) of the pure oil - which together give indications of tramp oil infi ltration, oil discharge and been determined chemometrically. Chemometr ical analysis other changes in the cooling lubricant composition, have is faster than the customary techniques by roughly a factor of 3.