Institut De Recherches De La Siderurgie Francaise

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Institut De Recherches De La Siderurgie Francaise (irsid)

Gerard Willay

Andre Wittmann

Bernard Boury

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 n.sub.i, C.sub.i for all the channels located beyond the gaussian part, on the high intensity side, where n.sub.i and C.sub.i are the number of pulses in channel i, and the middle intensity of channel i, respectively.

Process for determining, by optical emission spectrometry, the content

A composite crucible for melting by an induction process samples to be analyzed is placed in the interior of an induction heating coil supplied with electric current ofhigh frequency. The composite crucible is constituted by two containers, one inserted into the other with a small play between the containers. The outer container is of platinum or a platinum alloy, and the inner container is of refractory material of good heat conductive characteristics, preferably vitreous carbon, and is destined to receive the sample to be melted.

Composite crucible

An apparatus for preparing test samples for chemical analytical testing has an electric coil adapted to receive a crucible and connected to a source of electricity. The crucible is formed by an outer vessel of a noble metal and by an inner vessel formed of a rigid refractory material that is a good conductor of heat and that is not wettable by the sample. Normally platinum or a platinum alloy is used for the outer vessel and vitreous carbon is used for the inner vessel. The apparatus further comprises a high-frequency electricity supply for supplying electricity to the coil and thereby heating the crucible and the sample therein, a casting receptacle at a lower station below the upper station and adapted to receive the melted sample, a dissolving receptacle at the lower station, and a bath of a solvent for the sample in the dissolving receptacle.

Apparatus for preparing test samples

An apparatus for the preparation of a sample for X-ray spectrometry comprises a crucible for fusible material, a vessel covering the crucible in a first position and serving to receive cast material from the crucible in a second position, an induction coil wherein the crucible is disposed for simultaneously heating the crucible until the material therein is fused and preheating the vessel covering the crucible, a mobile support mounted for rotation about a horizontal axis extending perpendicularly to the axis of the induction coil, the induction coil being affixed to the support and rotation of the support being capable of agitating the crucible during fusion of the material and for turning the crucible from an upright position wherein the material is fused to a casting position wherein the fused material is cast from the crucible, a casting table below the induction coil, and a sliding ramp connecting the casting table to the mobile support for slidingly guiding the vessel from the first to the second position below the crucible when the crucible is turned into the casting position.

Apparatus for the automatic preparation of an X-ray spectrometry sample

Apparatus for the automatic preparation of samples for analysis comprises a tubular fusion furnace and a casting device. The furnace is horizontally disposed and permits introduction and removal of crucibles with samples through its two open ends. Transport equipment assures a periodical progression of the crucibles in the interior of the tubular furnace in successive and repeating states. The samples are agitated during momentary stops of the crucibles in their periodic progression.

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Ars sur Moselle, France

Gerard Willay