Abstract. The inclusion control procedures and software for dynamic modelling of ladle treatment technologies were developed to control of steel cleanliness, to detect sources of inclusions origin and to increase the steels quality. The method of quantitative metallography, X-ray microprobe and fractional gas analysis were applied for the basic oxygen species identification and their quantity determination in the probes sampled from the ladle furnace, ladle vacuum degasser and tundish during the ladle treatment and casting of these steels.M.The results of application software through a rational technology of melting and secondary steel treatment were carried out.