For the purpose of the process control in continuous steelmaking, a new method of G. P. (giant pulse) laser direct spectrochemical analysis of C, Si, Mn in liquid iron has been developped. This method is characterized by coincidence of optical axis of laser and spectrometer. In this study, fundamental conditions for the analysis of C, Si, Mn, especially taking a serious view of C, has been studied. The following results have been obtained:
(1) Influence of variations in the level of liquid iron surface on spectral intensities and intensity ratios has been evaluated. It has been shown that, for the purpose of minimization of these influences, intensity ratio should be used.
(2) Si and Mn analysis are possible with the use of cylinder type and cone type atmosphere controlling apparatus.
(3) In C analysis, it has been shown that CO gas generated in the surface of liquid iron have effects upon spectral intensity of C I 193.1nm, and these effects can be eliminated by using cone type atmosphere controlling apparatus. C analysis is possible with the use of this apparatus.
