PROCESS FOR THE DETERMINATION, BY WAY OF OPTICAL EMISSION SPECTROMETRY, THE CONCENTRATION OF STEEL IN AN ELEMENT, SUCH AS ALUMINIUM, BOTH DISSOLVED AND PRECIPITATED

摘要

A sample of the steel to be analyzed is subjected to spark discharging, the optical emission of the sparks is directed onto a diffraction grating in order to separate the light emission corresponding to the element to be metered and a capacitor is charged by a current respective of the intensity of this radiation; after every elementary discharge of the integration circuit, the charge of the capacity is converted into the form of a digital data representative of the intensity of the line selected; during a spark discharging cycle, the number of intensities is determined of which the value is included in each one of a plurality of contiguous channels, in order to set up an intensity frequency diagram as a function of the intensity; the curve representing the diagram is smoothed and the content of dissolved element is determined as a linear function of the value of light intensity corresponding to the peak of the gaussian part of the smoothed curve; and the content of precipitated element is determined by summing products ni, Ci for all the channels located beyond the gaussian part, on the high intensity side, where ni and Ci are the number of pulses in channel i, and the middle intensity of channel i, respectively.