Method and device for the determination by optical emission spectrometry of an element such as aluminium present in a dissolved and precipitated state in a metal such as steel

摘要

1. A process for determining the dissolved and precipitated concentrations of an element, such as aluminium, in a metallic analysis sample by Optical Emission Spectrometry, in particular a steel sample, comprising the steps of - submitting the sample to mild spark erosion conditions for the entire duration of the analysis in such a way as to avoid any phenomenon of local refusion of the sample, and sufficiently mild so as not to draw out the subcutaneous inclusions of the precipitated element, - dividing the spark erosion profile in time, that is thus obtained for the element under analysis, in at least two successive parts : an initial part formed by a peak (19) and a terminal part formed by a horizontal flat portion (20), - considering the standardized values of the intensities of the spark erosion profile, - determining said concentrations on the basis of said standardized values by reading on calibrating charts set on known samples, - considering a standardized value V1 of the intensity of the peak (19) of the spark erosion profile and a value V2 of the intensity of the horizontal flat portion (20) of the spark erosion profile, - determining on the basis of V1 -V2 and a corresponding calibrating chart the concentration [M]p in the precipitated state of the element M under analysis, - determining on the basis of V2 and a corresponding calibrating chart the concentration in the dissolved state [M]d of the element under analysis, - determining the total concentration [M]t of the element under analysis by the sum of the concentrations in the dissolved state and the precipitated state [M]d + [M]p .