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Determination of small quantities of impurities in hydrogen
Classified
abstracts
1573-1589
31 1578. Vacuum casting and product requirements which justify its use at the present time. (Spain) Vacuum degassing has become a requirement in the production of many grades of high quality steel. The need to eliminate costly rejects of finished or partially finished parts due to the effects of adsorbed gases has led to increasing demands for vacuum degassed steels. By vacuum degassing the concentration of most gases in the steel can be made acceptable. In addition greater homogeneity and partial elimination of such impurities as As, Sb, Sn, Cu, and Pb can be obtained. Advantages and uses of the different degassing procedures are given. J V Lopez, An Met Elec, 43, 1966,265-283. 31 1579. Degassing of steels in vacuum. (Spain) The possibility of minimizing the HZ, 0, and N, contents in steel is considered. Hydrogen is removed by a vacuum treatment before solidification of the steel, the equilibrium constant for the reaction 2H+H, at 1600” being 30fH/pHa, where H is the He content in the steel in mil/lOOg and pH, is the HP partial pressure in the equilibrium atmosphere. Degassing apparatus, operating costs and the most important fnms in the field, are reviewed. J M Kindelan and L Miranda, Electron Fis Applicada, 9, 1966, 369377, (in Spanish). 37 1580. Floating zone melting of refractory metals by electron bombardment. Part e. The electron beam melting of refractory metals. (Japan) An electron beam floating zone melting apparatus has been assembled. The apparatus consists of four components: vacuum system, power supply, anode supports and traversing cathode. A maximum acceleration voltage of 10 kV is supplied to the specimen (anode) while the tungsten filament (cathode) is nearly at earth potential. Electron beam concentrators made of Ta discs were found to be effective for obtaining higher temperatures in specimen rods. T Takaai, Jap Znst Metals J, 30, 1966, 1017-1021 (in Japanese). 37 1581. An experimental study on the fatigue strength of carbon steels. (Japan) The effect of carbon content on the fatigue strength of plain carbon steels under normalised (air-cooled) and fully annealed (furnace cooled) conditions was examined experimentally. Five different types of carbon steels were produced in an induction furnace by remelting a low carbon steel containing 0.12 per cent carbon and adding predetermined portions of highly pure pig ion, ferrosilicon and low carbon ferromanganese. After heat treatment and cooling, fatigue tests by rotary bending were performed with specimens which were annealed at 65O”C, for one hour, in vacuum. Normalised steels had a slightly higher fatigue limit than the annealed steels. E Tsuji et al, “Foundation of National Research Znsr of Metals” Tokyo, 1966, 189-190. 3-l 1582. Effects of specimen thickness and orientation on weight loss of a-brass single crystals due to heating in vacuum. (Japan) Alpha-brass single crystals whose surfaces are parallel to the (lOO), (11 l), and (112) planes were heated at various temperatures in vacuum and the effects of their thickness and orientation on the weight loss during heating were studied. Dislocation arrangements were examined by an etch-pit technique and by electron microscope. H Yamaguchi, Japan J Appl Phys, 6, 1967,447-453. 37 : 16 1583. Device for local mass-spectrometer analysis of absorbed gases in metals and alloys. (USSR) A sample with a clean surface is placed in a chamber at 10-O torr pressure, and exposed to an electron beam for about one second to melt several points on the sample. The extracted gases are measured by an LM-2 ionization gauge and by an MKh-1302 mass-spectrometer tuned to one selected gas. The minimum point diameter analyzed was 0.15 mm and sensitivities by weight of lo-* for hydrogen and 3 x lo-’ for oxygen were determined. As an example, the density distribution of hydrogen on a nickel sample is presented and it is shown that at the centre of grains the hydrogen content is, at most, half at the grain boundaries. 0 D Smiyan, Zuvodsk Lab, 33 (5), 1967, 637-639 (in Russian).
37 1584. Mechanism of melting crystalline solids by an electron beam. (USSR) Formation of knife shapes in the melting of a crystalline solid body by an electron beam of small diameter and high energy, is explained as the action of shock waves induced by the short term overheating of a thin surface layer. For example, when a beam of 150 keV energy, 9 mA current density, 0.3 mm in diameter and of 23 microseconds duration, is applied to steel, the pressure of the shock wave front is about lOlo N/me and the power transferred to each atom by the front of moving dislocations is more than 3 x lo-*O J, which is sufficient to melt the solid body. I V Zuev et al, Dokl Akad Nauk SSSR, 174 (l), 1st May 1967,76-79 (in Russian). 37 1585. Determination of small quantities of impurities in hydrogen. (USSR) Measured amounts of hydrogen were driven through silicagel at -196°C and the silicagel subsequently heated to + 150°C. Desorbed gases were analysed by an MKh-1302 mass-spectrometer. The sensitivity of the method was 10 ppb for one cubic metre of hydrogen. E K Vasil’eva and A G Zakomomyi, Zavodsk Lab, 33 (4), 1967,471 (in Russian). 31 1586. Metal sample testing. (Great Britain) For determining the combined nitrogen and carbon monoxide content of the gases given off by a series of metal samples, ie by means of automatic gas analysis equipment, the method consists in fusing a sample in a carbon or graphite crucible in a furnace under vacuum; admitting gaseous hydrogen into the gas mixture formed in the furnace until a predetermined total pressure is reached; and then measuring the thermal conductivity of the mixture, from which the total content of nitrogen and carbon monoxide may be calculated and from which calculated result, the oxygen content may be determined. Balzers Pat- Lizenz-Anst, Brit Patents 1,068,214-5, Patent AbsW, 7 (22) part I, 2nd June 1967, 2. 38. DISTILLATION, ANALYSIS
ORGANIC
CHEMISTRY, ISOTOPIC GAS
38 1587. Low pressure distillation. (USA) Several types of rectifying sections having low pressure drop for low pressure distillation are described. P J King, Process Biochem, 2, 1967, 25-30. 38 1588. Contacting devices for vacuum distillation. (Great Britain) Some new packings to reduce the thermal hazard in vacuum distillation are reviewed, especially for l-20 mm pressure. Requisites for such packing are small height of packing per theoretical plate, high operating throughput and flexibility of operation, and low pressure drop per theoretical plate. Means for achieving these are presented. K E Porter et al, Chem Znd, 1967, 182-188.
IV. Materials technology
and techniques
42. GLASS, CERAMICS
used in vacuum
AND REFRACTORY
OXIDES
42 : 25 1589. Destruction of synthetic zeolite crystals in pressure processinp. (USSR) The influence of the value of the pressure, used to make pellets from NaX, NaA and CaA zeolite powders, on their characteristics, was investigated. Weak changes in adsorption isotherms were observed at a pressure of 8,000 kg/cm2 and when processing pressures of 15,ooO kg/cm2 were used the values for Ar, C,H, and H,O are 3 times lower and the external surface of zeolites is 4 times higher. These changes are caused by the destruction of zeolite crystals during processing. V Bosacek et al, Dokl Akad Nauk SSSR, 174 (l), 1st May 1967, 117-120 (in Russian). 543
abstracts
1573-1589
31 1578. Vacuum casting and product requirements which justify its use at the present time. (Spain) Vacuum degassing has become a requirement in the production of many grades of high quality steel. The need to eliminate costly rejects of finished or partially finished parts due to the effects of adsorbed gases has led to increasing demands for vacuum degassed steels. By vacuum degassing the concentration of most gases in the steel can be made acceptable. In addition greater homogeneity and partial elimination of such impurities as As, Sb, Sn, Cu, and Pb can be obtained. Advantages and uses of the different degassing procedures are given. J V Lopez, An Met Elec, 43, 1966,265-283. 31 1579. Degassing of steels in vacuum. (Spain) The possibility of minimizing the HZ, 0, and N, contents in steel is considered. Hydrogen is removed by a vacuum treatment before solidification of the steel, the equilibrium constant for the reaction 2H+H, at 1600” being 30fH/pHa, where H is the He content in the steel in mil/lOOg and pH, is the HP partial pressure in the equilibrium atmosphere. Degassing apparatus, operating costs and the most important fnms in the field, are reviewed. J M Kindelan and L Miranda, Electron Fis Applicada, 9, 1966, 369377, (in Spanish). 37 1580. Floating zone melting of refractory metals by electron bombardment. Part e. The electron beam melting of refractory metals. (Japan) An electron beam floating zone melting apparatus has been assembled. The apparatus consists of four components: vacuum system, power supply, anode supports and traversing cathode. A maximum acceleration voltage of 10 kV is supplied to the specimen (anode) while the tungsten filament (cathode) is nearly at earth potential. Electron beam concentrators made of Ta discs were found to be effective for obtaining higher temperatures in specimen rods. T Takaai, Jap Znst Metals J, 30, 1966, 1017-1021 (in Japanese). 37 1581. An experimental study on the fatigue strength of carbon steels. (Japan) The effect of carbon content on the fatigue strength of plain carbon steels under normalised (air-cooled) and fully annealed (furnace cooled) conditions was examined experimentally. Five different types of carbon steels were produced in an induction furnace by remelting a low carbon steel containing 0.12 per cent carbon and adding predetermined portions of highly pure pig ion, ferrosilicon and low carbon ferromanganese. After heat treatment and cooling, fatigue tests by rotary bending were performed with specimens which were annealed at 65O”C, for one hour, in vacuum. Normalised steels had a slightly higher fatigue limit than the annealed steels. E Tsuji et al, “Foundation of National Research Znsr of Metals” Tokyo, 1966, 189-190. 3-l 1582. Effects of specimen thickness and orientation on weight loss of a-brass single crystals due to heating in vacuum. (Japan) Alpha-brass single crystals whose surfaces are parallel to the (lOO), (11 l), and (112) planes were heated at various temperatures in vacuum and the effects of their thickness and orientation on the weight loss during heating were studied. Dislocation arrangements were examined by an etch-pit technique and by electron microscope. H Yamaguchi, Japan J Appl Phys, 6, 1967,447-453. 37 : 16 1583. Device for local mass-spectrometer analysis of absorbed gases in metals and alloys. (USSR) A sample with a clean surface is placed in a chamber at 10-O torr pressure, and exposed to an electron beam for about one second to melt several points on the sample. The extracted gases are measured by an LM-2 ionization gauge and by an MKh-1302 mass-spectrometer tuned to one selected gas. The minimum point diameter analyzed was 0.15 mm and sensitivities by weight of lo-* for hydrogen and 3 x lo-’ for oxygen were determined. As an example, the density distribution of hydrogen on a nickel sample is presented and it is shown that at the centre of grains the hydrogen content is, at most, half at the grain boundaries. 0 D Smiyan, Zuvodsk Lab, 33 (5), 1967, 637-639 (in Russian).
37 1584. Mechanism of melting crystalline solids by an electron beam. (USSR) Formation of knife shapes in the melting of a crystalline solid body by an electron beam of small diameter and high energy, is explained as the action of shock waves induced by the short term overheating of a thin surface layer. For example, when a beam of 150 keV energy, 9 mA current density, 0.3 mm in diameter and of 23 microseconds duration, is applied to steel, the pressure of the shock wave front is about lOlo N/me and the power transferred to each atom by the front of moving dislocations is more than 3 x lo-*O J, which is sufficient to melt the solid body. I V Zuev et al, Dokl Akad Nauk SSSR, 174 (l), 1st May 1967,76-79 (in Russian). 37 1585. Determination of small quantities of impurities in hydrogen. (USSR) Measured amounts of hydrogen were driven through silicagel at -196°C and the silicagel subsequently heated to + 150°C. Desorbed gases were analysed by an MKh-1302 mass-spectrometer. The sensitivity of the method was 10 ppb for one cubic metre of hydrogen. E K Vasil’eva and A G Zakomomyi, Zavodsk Lab, 33 (4), 1967,471 (in Russian). 31 1586. Metal sample testing. (Great Britain) For determining the combined nitrogen and carbon monoxide content of the gases given off by a series of metal samples, ie by means of automatic gas analysis equipment, the method consists in fusing a sample in a carbon or graphite crucible in a furnace under vacuum; admitting gaseous hydrogen into the gas mixture formed in the furnace until a predetermined total pressure is reached; and then measuring the thermal conductivity of the mixture, from which the total content of nitrogen and carbon monoxide may be calculated and from which calculated result, the oxygen content may be determined. Balzers Pat- Lizenz-Anst, Brit Patents 1,068,214-5, Patent AbsW, 7 (22) part I, 2nd June 1967, 2. 38. DISTILLATION, ANALYSIS
ORGANIC
CHEMISTRY, ISOTOPIC GAS
38 1587. Low pressure distillation. (USA) Several types of rectifying sections having low pressure drop for low pressure distillation are described. P J King, Process Biochem, 2, 1967, 25-30. 38 1588. Contacting devices for vacuum distillation. (Great Britain) Some new packings to reduce the thermal hazard in vacuum distillation are reviewed, especially for l-20 mm pressure. Requisites for such packing are small height of packing per theoretical plate, high operating throughput and flexibility of operation, and low pressure drop per theoretical plate. Means for achieving these are presented. K E Porter et al, Chem Znd, 1967, 182-188.
IV. Materials technology
and techniques
42. GLASS, CERAMICS
used in vacuum
AND REFRACTORY
OXIDES
42 : 25 1589. Destruction of synthetic zeolite crystals in pressure processinp. (USSR) The influence of the value of the pressure, used to make pellets from NaX, NaA and CaA zeolite powders, on their characteristics, was investigated. Weak changes in adsorption isotherms were observed at a pressure of 8,000 kg/cm2 and when processing pressures of 15,ooO kg/cm2 were used the values for Ar, C,H, and H,O are 3 times lower and the external surface of zeolites is 4 times higher. These changes are caused by the destruction of zeolite crystals during processing. V Bosacek et al, Dokl Akad Nauk SSSR, 174 (l), 1st May 1967, 117-120 (in Russian). 543