SE330625B - - Google Patents

Abstract

1,183,252. Photo-electric measurement of gas content of metals. CENTRALNY NAOUTCHNO ISSLEDOVATELSKY INSTITUT TCHORNOY METALLOURGY "I. P. BARDINE". April 7, 1967 [April 15, 1966], No. 16080/67. Heading G1A. The gas content of a metal is measured by photo-electrically detecting radiation, characteristic of the gas, obtained when a spark is produced between an electrode and the surface of a specimen of the metal. A specimen for analysis is obtained by taking a sample from a bath of molten metal which is being monitored, cooling the sample and cutting off a small element of e.g. 15-20 mm thickness using a known cutting tool. The specimen or element 11 is then placed over an aperture 3 in plate 2 of the apparatus shown in Fig. 2. The cut surface of the specimen is arranged to face a pointed electrode 5, the specimen being positioned eccentrically, so that rotation will align different points on the specimen surface with point 6 of the electrode. The specimen is held in position by a bar carried in notches 13 of two supports 14. An inert gas e.g. helium, argon, or nitrogen is passed through the enclosure 1, via inlet and outlet conduits 8, 10. A spark is formed for about 0À2 sec. between electrode 5 and the specimen 11, the radiation produced passing through window 17 and being formed into a spectrum by an optical system 18 and the spectral line for the gas of interest being detected by a photo-multiplier. A number of measurements may be made with the specimen rotated to allow examination of different points of the surface. The measurements are compared with a calibration curve obtained with standard specimens. The method and apparatus is applicable to the determination of oxygen in effervescent, semikilled or killed steels at the molten stage before casting.