LU85603A1 - Steel spectral analysis specimen treatment unit - comprising inert gas shielded arcing electrode - Google Patents

Abstract

The unit comprises a cooled metal specimen holder, an electrode directed towards the specimen holder, a system for forming an electric arc between the electrode and the specimen, and a system for forming an inert gas curtain around the arc. The unit is used for eliminating inclusions from the zone of the specimen to be subjected to spectral analysis, e.g. to determine the soluble aluminium content of steels. Use of an inert gas curtain instead of a chamber, which requires evacuation and inert gas filling, reduces inert gas consumption and the prepn. time for the specimen, the latter being important in control of continuous casting processes.

Description

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4 ”C 2274/8310.

METALLURGICAL RESEARCH CENTER -CENTRUM V00R RESEARCH IN DE METALLURGIE,

Non-profit association -Vereniging zonder winstoogmerk in BRUXELLES, (Belgium) and

COCKERILL SAMBRE

1 Société Anonyme, in SERAING, (Belgium).

3 Improvement to a facility for processing a steel sample.

The present invention relates to an improvement to an in-! tallation for the treatment of a steel sample intended | spectral analysis.

I A process for treating such a steel sample is already known, in which the sample is placed in an enclosure 1 where an inert atmosphere is maintained and subjected to fusion {! local to the electric arc. This process eliminates inclusions from the area by derision, which will then, after peeling, be subjected to spectral analysis.

I / / ”2.- There is currently an installation making it possible to implement the process which has just been recalled, this known installation essentially consists (1) of an enclosure comprising a cooled metal support, intended to receive the sample, and an electrode connected to a high intensity electrical source, (2) of a reservoir communicating with the enclosure and connected to a vacuum pump, (3) of an inert gas supply source connected to the volume inside the enclosure.

The process for treating a steel sample, mentioned above, makes it possible to improve the reliability of the determination, by spectral analysis, of the soluble aluminum of the steels, even if the latter are loaded with alumina.

The speed of this determination is however greatly handicapped by the time required to process the sample by means of an installation of known type.

Currently, the time required for this treatment performed by an experienced operator is around 15 minutes. Such a duration is no longer acceptable in the current state of development of continuous casting processes, where it is important to know the results of an analysis within a period not exceeding a few minutes, in order to remedy as soon as possible the any defects found.

The subject of the present invention is an improved installation which makes it possible to remedy this drawback by greatly reducing the time necessary for the preparation of the steel sample.

To this end, the installation which is the subject of the present invention is essentially characterized in that it comprises, in combination, a cooled metal support intended to receive / "" 3.-

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ft see the steel sample to be treated, an electrode directed towards said support, means for establishing an electric arc between the electrode and the sample deposited on said support and means for forming a curtain of inert gas around of the said electric arc.

According to the invention, the means for forming an inert gas curtain are constituted by an annular duct, arranged around the electrode and in the vicinity of the end of the latter, and provided at its lower part with a series of orifices directed towards said support.

In an advantageous variant, the said annular duct is provided, at its lower part, with a slot directed towards the said support and extending at least over the major part of the length of the said duct.

Also according to the invention, the installation can include means making it possible to synchronize, preferably automatically, the establishment and stopping of the electric arc and the curtain of inert gas.

Of course, it would not depart from the scope of the invention to surround, in a manner known per se, the area where the electric arc and the curtain of inert gas are formed, with a protective device, in order to avoid any disturbance or extinction of the arc by an undesirable draft.

The use of an installation in accordance with the invention makes it possible to reduce, to a very large extent, the time necessary for processing the sample, since it no longer requires vacuuming and purging of a sealed enclosure and then filling it with inert gas. It also makes it possible to significantly reduce the consumption of this inert gas.

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Claims (3)

1. Installation for the treatment of a steel sample intended for spectral analysis, characterized in that it comprises in combination: <a) a cooled metal support, intended to receive the steel sample to be treated? (b) an electrode directed towards said support; (c) means for establishing an electric arc between the electrode and the sample deposited on said support; (d) means for forming a curtain of inert gas around said electric arc. 2. Installation according to claim 1, characterized in that said means for forming a curtain of inert gas consist of an annular conduit, disposed around said electrode and in the vicinity of the end thereof, and provided with its lower part of a slot or a series of orifices directed towards said support. 3. Installation according to either of claims 1 and 2, characterized in that it comprises means for synchronizing, preferably automatically, the establishment and / or stopping of the electric arc and of the inert gas curtain. Drawings: ........ ^ r ... plates ______ £ ...... pages of which ..... A .... cover page ....... v2 ... ... description pages ....... Λ ..... claim pages ....... A ..... short description Luxembourg, OCT 24. 1984 The agent; . / dd, Me Alain | '' //