144. High vacuum distillation

144. High vacuum distillation

Classified abstracts 144--157 36 144. High vacuum distillation. (USA) D B Greenberg, Dissertation Abst, 25 (10), 1965, 5089. 37. Metallurgy, inorgan...

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Classified abstracts 144--157 36

144. High vacuum distillation. (USA) D B Greenberg, Dissertation Abst, 25 (10), 1965, 5089.

37. Metallurgy, inorganic chemistry, analytical chemistry 37 : 16 : 40 Improvements in the purification of argon and helium gases. See abstract n u m b e r 20. 37:17 Some principles that govern the bulk condensation of metals and alloys. See abstract n u m b e r 28. 37:21 Pump improves spark source technique. See abstract n u m b e r 53. 37 : 33 Electrode materials for caesium contact ion engines. See abstract n u m b e r 132. 37 : 33 Solid state physics vol 17. Advances in research and applications. See abstract n u m b e r 133. 37 145. Vacuum degassing of steel. (Spain) J V Lnpez, Anales Mecan Elec (Madrid) 41, 1964, 439 446 a n d 42,

1965, 23-35. 37

146. Vacuum degassing--why and how ? ( U S A ) J H Hornak, Iron Steel Engr, 42 (6), 1965, 73 80. 37 : 41 147. Vacuum degassing of steel. (Great Britain) The article summarizes papers presented on the subject at meetings held at the Iron and Steel Institute on 5-6 M a y 1965. D u r i n g the past three years the n u m b e r of different m e t h o d s available has increased f r o m 8 to 14, a n d these m a y be classified into (a) ladle, (b) stream, (c) circulation and v a c u u m lift, and (d) ingot groups of degassing processes. D u r i n g this period the main developments have been: (1) use of induction stirring in conjunction with ladle degassing; (2) application of induction rather t h a n gas lift p u m p s for raising the metal in a circulation process; (3) increase in treatment time; and (4) reheating after degassing. The distribution of plants is as follows: 10 n tons ingot production No. of Installed Degassing capacity per plants tonnage 106 tons ingot production UK 22 1356 60.2 Europe 66 3317 30.2 Japan 39 1697 54.7 U S A and C a n a d a 59 5797 55.3 USSR 18 962 12.2 Where the type of process is known, an analysis, in terms of the type of process gives the following figures: Installed Average Maximum Number tonnage (tons) (tons) Ladle 67 2815 42.0 250 Stream 126 7646 60.8 3l 5 Circulation and v a c u u m lift 36 3696 102.8 360 Ingot 6 -6.0 8 Brief details are given of some British plants. It is pointed out that steam-jet ejectors have almost completely replaced the mechanical p u m p s used in early plants with a consequent reduction in operating pressure f r o m 5 m m H g to 0.5 m m Hg or even 0.1 m m Hg. The article concludes by s u m m a r i z i n g a paper on " T h e Future of V a c u u m Degassing". It is stated that to users of the right v a c u u m degassing e q u i p m e n t hydrogen has almost ceased to be a problem. However, the oxygen and nitrogen contents are only significantly reduced in certain steels while only m a n g a n e s e is appreciably removed in n o r m a l degassing processes. V a c u u m degassing is becoming i m p o r t a n t in alloy steelmaking but it remains to be seen whether the technique can be improved sufficiently to avoid the necessity for re-melting under v a c u u m in cases when this is at present specified by the user. In reviewing future developments the v a c u u m treatment of bulk steel is discussed and it is claimed that costs well under £1 per ton of steel degassed should be achievable. It is anticipated that it will eventually become necessary to integrate the v a c u u m degassing process into plants designed for the continuous production of iron a n d steel. T H Turner, Engineer, 220 (5711), 9 July 1965, 57 58.

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37 : 28 : 42 148. Performance of niobium heaters in a vacuum furnace with ceramic insulation. ( USSR ) The investigation relates to the performance, for an extended duration, of n i o b i u m heaters when used in a laboratory v a c u u m electric furnace at temperatures up to 1800°C and pressures of 10 -4 to 10 5 tort. The furnace was lined with zirconium oxide, c o r u n d u m or a high-alumina refractory. The results of the experimental work and analyses show that n i o b i u m interacts with industrial grades of the refractories employed. It is concluded, therefore, that niobium is not a suitable material for the heaters used in v a c u u m furnaces under the conditions specified when the refractories mentioned are present. I A Etinger et al, Elektroterm~va, 45, 1965, 42, (in Russian). 37 : 47 149. Gas evolution from silicon steel heated in vacuum. (USSR) Consideration is given to s o m e features of gas evolution f r o m coldrolled transformer steel, containing 3 per cent silicon, when heated in vacuum. The experimental work is described a n d the resulting data are presented and discussed. The conclusions reached indicate that, for steel of the kind specified, heating in v a c u u m at temperatures of 1100 °C to 1150 °C and at pressures of the order of 10 -4 torr causes the evolution of 16 cm* to 20 cm 3 of gas mixture per I00 g m of the metal, the gas being composed mainly of hydrogen, nitrogen and carbon monoxide. It was also established that about 75 per cent of the gas was evolved during the first 10 to 12 minutes of processing a given sample at a given temperature. The data presented is of interest in connection with the calculation of p u m p i n g capacities suitable for v a c u u m furnace systems. (USSR) V E Kochnov, Elektrotermiya, 45, 1965, 49, (in Russian). 37 150. Measuring gas traces in metallurgical analysis. (Great Britain) Anon, Engineer, 219 (5708), 18 June 1965, 1063. 37 : 49 151. Effects of space vacuum on metals. (USA) L J Bonis, Space~Aeronautics, 43, 1965, 76-84. 37 152. Far-infrared vacuum grating spectrometer. (USA) K D Muller et al, J Opt Soc Amer, 55 (10), Oct 1965, 1233-

1238. 37 153. Theory and applications of vacuum mierobalance techniques.

(Great Britain) J M Thomas and B R Williams, Quarterly Review, 19 (3), 1965,

231-254. 37 154. Transport properties of partially ionized monatomic gases.

( USA ) R S de Voto, A1AA, July 1965, 65-540. 37 155. The use of a continuous slow injector for the production of calibration vapour mixtures in the parts per million by volume range.

(Great Britain) A slow injection system is described for the production of low concentration organic vapour mixtures in the parts per million by volume range. This a r r a n g e m e n t has proved to be very suitable for the calibration of ionization detectors for gas c h r o m a t o g r a p h y and for sensitive infrared gas analysis. D W Hill and H A Newell, JScient Instrum, 42, Nov 1965, 783-786. 37 156. Inexpensive simple high vacuum injection system for gas chromatography. (USA) W H Wahl and G G Meisels, Rev Scient Instrum, 36 (10), Oct 1965,

1508-1509. 37 157. Determination of oxygen, nitrogen and hydrogen in metals.

(France) The working principle and the construction of the equipment for the determination of O~, N~ and H2 in metals are described in detail. These gases are extracted by fusion-reduction in helium atmosphere and analyzed by chromatography. The characteristics of the performance of the e q u i p m e n t are illustrated by precise examples showing the determination of gases in samples of steel, titanium alloys and niobium. (France) P Esotlier, Recherches Adrospatiale, 106, May-June 1965, 25-38,

(in French).