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866. Physical considerations in the stream degassing of steel
Classified abstracts 858-866 34 : 22 858. Vacuum measurement techniques applied to aeronomy. (France) Recent developments in instruments used for determining the chemical and ionic composition of the upper atmosphere are given in a general survey. (10 references). G Israel, Le Vide, 20 (116), March-April 1965, 95-99, (in French).
37. Metallurgy, inorganic chemistry, analytical chemistry 37 : 30 : 33 Vacuum ultraviolet reflectometer. See abstract number 850. 37 • 30 : 33 Internal stress of evaporated thin gold films. See abstract number 851. 37 : 30 : 33 Determination of structure of thin films by electron microscope examination. See abstract number 852. 37 : 30 : 33 Initial stages in formation of a thin, evaporated film. See abstract n u m b e r 853. 37 : 33 Excitation of spin waves in thin ferromagnetic films. See abstract number 857. 37 : 20 : 53 859. Vacuum degassing 1955-1965: A survey of processes and plant for bulk steel production. (Great Britain) Having briefly traced the early use of vacuum technique for degassing molten steel, the author discusses the development of various processes between 1955 and 1965. Fourteen different methods of degassing are illustrated and there are a series of eight graphs which analyse the cumulative growth of vacuum degassing by process and the annual rate of installation by process between 1951 and 1964. The analyses pin-point the activity in the main countries concerned viz Europe, Japan, USA, Canada, USSR, and also the relationships between numbers of plants and tonnage capacity. The paper also covers the main aspects of plant design and particularly the use of steam ejection pump systems. Finally, details of 204 actual installations are compared in table form and there is a bibliography of 112 references. (Great Britain) J H Flux, Iron and Steel Institute Special Report No 92, London,
November 1965, (in press). 37 : 53 860. High vacuum ladle degassing with induction stirring at the Republic Steel Corporation. (Great Britain) This paper describes experience with induction stirred ladle vacuum degassing and shows how since November 1962 the process has permitted automation of the difficult deoxidation phase of steelmaking; it has also made possible the consistent upgrading of qualities in aircraft- and bearing-type steels on a production basis, notably in applications involving conditions of severe fatigue. There appear to be two mechanisms which improve performance: fewer internal notches in the form of inclusions and improved capacity in the steel matrix for redistribution of stress around sharp notches. The actual degassing process is described in some detail and it is noted that the effect of process-time below 100tzm is more important to the quality of the melt than is generally thought. There are four tables and twelve figures. (USA) T E Ferry, Iron and Steel Institute Special Report No 92, November
1965, (in press). 37 : 53 861. 110 Vacuum degassing plant at Samuel Fox & Company Limited. (Great Britain) Experience since September 1964 with another induction stirred ladle vacuum degassing plant (see Perry above) has evolved a technique for making 1 per cent C-Cr steel in which semi-skilled metal is presented to the vacuum chamber. This provides steel in which the oxygen is not completely tied up as stable oxides, and thus the carbon-oxygen reaction is more readily promoted. At the same time a modification to the standard Jernkontoret count has been devised which gives more detailed information on the reduction in the number (and length) of alumina trails and the number of r a n d o m globular oxides. There are four tables, seven figures and six references. (Great Britain) G W S Jackson et al, Iron and Steel Institute Special Report No 92,
November 1965, (in press).
524
37 : 53 862. Vacuum treatment of unalloyed and low-alloy steels.
(Great
Britain) This paper consists of two parts. The first part discusses the application of various vacuum treatments for steel. In particular, the effects of the technique on grain size, oxygen removal and steel cleanliness are discussed and illustrated with six graphs and two tables. In the second part a method of making additions to the melt by using a development of the Dortmund-Horder-Huttenunion vacuum lift technique is discussed. In this process the degassing effect of the installation is relatively of less importance than the fact that additions can be made in a controlled sequence without reactions with the slag or atmospheric oxygen. Two tables, six figures. (Germany) K Brotzmann, Iron and Steel Institute Special Report No 92,
No vember 1965, (in press). 37 : 53 : 20 863. Requirements for high-rate vacuum degassing of metal melts.
( Great Britain) With the object of determining the conditions in vacuum steel degassing which lead to the optimum degassing times, the authors analyse the formation and growth of bubbles in the melt. They also discuss the removal of gas from above the melt by vacuum pumping and confirm that the rate of degassing is determined by rate of material transfer within the melt and not by the pumping speed. The results indicate that maximum bubble formation is obtained by evacuation of the chamber to about 8 torr and at this pressure the highest material transfer takes place; lower pressures are only advantageous if the material transfer takes place solely by convection. Finally it was shown how the formulae derived in the analysis could be applied to optimise the design specification of modern steel degassing plant. (Leichtenstein) T Kraus and O Winkler, Iron and Steel Institute Special Report
No 92, November 1965, ( in press) . 37 : 53 864. Improvements
in manufacture
of large
forgings.
(Great
Britain) The author reviews the series of failures in the USA between 1953 and 1956 which led to the introduction of vacuum degassing in the production of large steel forgings for turbine and generator rotors. Some features of the vacuum degassing plants are described, as are some of the metallurgical techniques which have brought about improvements in quality. The mechanical properties which are now being obtained are discussed and compared with those of the period before the failures. (USA) H C Myers, Iron andSteel Institute Special Report No 92, November
1965, (inpress). 37 : 53 865. Manufacture of low-carbon steel by the R H degassing process.
( Great Britain) This paper describes the vacuum steel degassing equipment at the Fuji Iron and Steel Works Ltd and its operation since it was installed in May 1963. It goes on to describe the C-O reaction that takes place in the vacuum vessel during the treatment of undeoxidized low carbon steel and refers to the reduction of manganese and hydrogen. It is remarked that although the R H process completely eliminates any rim zone, the superior cleanness of the ingot, due to lack of additions and drop in oxygen content during treatment, ensures that the surface zone of the degassed ingot is quite the equal of ordinary rimming steel. One table, thirteen figures, 21 references and an Appendix showing calculations of residence time for steel undergoing degasification. (Japan) M Hirase, Iron and Steel Institute Special Report No 92, November
1965, (in press). 37 : 53 866. Physical considerations in the stream degassing of steel. (Great
Britain) This paper deals exclusively with ladle-to-ladle stream degassing although it is agreed that for certain applications there are advantages in stream dcgassing direct into the mould. The mechanisms of bubble and droplet formation are discussed in connection with the removal of hydrogen and oxygen in particular. Heat losses in 120 and 8 ton plants are considered with regard to methods of reducing them, There is one table, one figure, seven references and an Appendix showing the theoretical calculations for removal of hydrogen in stream degassing in which it is shown that droplets
37. Metallurgy, inorganic chemistry, analytical chemistry 37 : 30 : 33 Vacuum ultraviolet reflectometer. See abstract number 850. 37 • 30 : 33 Internal stress of evaporated thin gold films. See abstract number 851. 37 : 30 : 33 Determination of structure of thin films by electron microscope examination. See abstract number 852. 37 : 30 : 33 Initial stages in formation of a thin, evaporated film. See abstract n u m b e r 853. 37 : 33 Excitation of spin waves in thin ferromagnetic films. See abstract number 857. 37 : 20 : 53 859. Vacuum degassing 1955-1965: A survey of processes and plant for bulk steel production. (Great Britain) Having briefly traced the early use of vacuum technique for degassing molten steel, the author discusses the development of various processes between 1955 and 1965. Fourteen different methods of degassing are illustrated and there are a series of eight graphs which analyse the cumulative growth of vacuum degassing by process and the annual rate of installation by process between 1951 and 1964. The analyses pin-point the activity in the main countries concerned viz Europe, Japan, USA, Canada, USSR, and also the relationships between numbers of plants and tonnage capacity. The paper also covers the main aspects of plant design and particularly the use of steam ejection pump systems. Finally, details of 204 actual installations are compared in table form and there is a bibliography of 112 references. (Great Britain) J H Flux, Iron and Steel Institute Special Report No 92, London,
November 1965, (in press). 37 : 53 860. High vacuum ladle degassing with induction stirring at the Republic Steel Corporation. (Great Britain) This paper describes experience with induction stirred ladle vacuum degassing and shows how since November 1962 the process has permitted automation of the difficult deoxidation phase of steelmaking; it has also made possible the consistent upgrading of qualities in aircraft- and bearing-type steels on a production basis, notably in applications involving conditions of severe fatigue. There appear to be two mechanisms which improve performance: fewer internal notches in the form of inclusions and improved capacity in the steel matrix for redistribution of stress around sharp notches. The actual degassing process is described in some detail and it is noted that the effect of process-time below 100tzm is more important to the quality of the melt than is generally thought. There are four tables and twelve figures. (USA) T E Ferry, Iron and Steel Institute Special Report No 92, November
1965, (in press). 37 : 53 861. 110 Vacuum degassing plant at Samuel Fox & Company Limited. (Great Britain) Experience since September 1964 with another induction stirred ladle vacuum degassing plant (see Perry above) has evolved a technique for making 1 per cent C-Cr steel in which semi-skilled metal is presented to the vacuum chamber. This provides steel in which the oxygen is not completely tied up as stable oxides, and thus the carbon-oxygen reaction is more readily promoted. At the same time a modification to the standard Jernkontoret count has been devised which gives more detailed information on the reduction in the number (and length) of alumina trails and the number of r a n d o m globular oxides. There are four tables, seven figures and six references. (Great Britain) G W S Jackson et al, Iron and Steel Institute Special Report No 92,
November 1965, (in press).
524
37 : 53 862. Vacuum treatment of unalloyed and low-alloy steels.
(Great
Britain) This paper consists of two parts. The first part discusses the application of various vacuum treatments for steel. In particular, the effects of the technique on grain size, oxygen removal and steel cleanliness are discussed and illustrated with six graphs and two tables. In the second part a method of making additions to the melt by using a development of the Dortmund-Horder-Huttenunion vacuum lift technique is discussed. In this process the degassing effect of the installation is relatively of less importance than the fact that additions can be made in a controlled sequence without reactions with the slag or atmospheric oxygen. Two tables, six figures. (Germany) K Brotzmann, Iron and Steel Institute Special Report No 92,
No vember 1965, (in press). 37 : 53 : 20 863. Requirements for high-rate vacuum degassing of metal melts.
( Great Britain) With the object of determining the conditions in vacuum steel degassing which lead to the optimum degassing times, the authors analyse the formation and growth of bubbles in the melt. They also discuss the removal of gas from above the melt by vacuum pumping and confirm that the rate of degassing is determined by rate of material transfer within the melt and not by the pumping speed. The results indicate that maximum bubble formation is obtained by evacuation of the chamber to about 8 torr and at this pressure the highest material transfer takes place; lower pressures are only advantageous if the material transfer takes place solely by convection. Finally it was shown how the formulae derived in the analysis could be applied to optimise the design specification of modern steel degassing plant. (Leichtenstein) T Kraus and O Winkler, Iron and Steel Institute Special Report
No 92, November 1965, ( in press) . 37 : 53 864. Improvements
in manufacture
of large
forgings.
(Great
Britain) The author reviews the series of failures in the USA between 1953 and 1956 which led to the introduction of vacuum degassing in the production of large steel forgings for turbine and generator rotors. Some features of the vacuum degassing plants are described, as are some of the metallurgical techniques which have brought about improvements in quality. The mechanical properties which are now being obtained are discussed and compared with those of the period before the failures. (USA) H C Myers, Iron andSteel Institute Special Report No 92, November
1965, (inpress). 37 : 53 865. Manufacture of low-carbon steel by the R H degassing process.
( Great Britain) This paper describes the vacuum steel degassing equipment at the Fuji Iron and Steel Works Ltd and its operation since it was installed in May 1963. It goes on to describe the C-O reaction that takes place in the vacuum vessel during the treatment of undeoxidized low carbon steel and refers to the reduction of manganese and hydrogen. It is remarked that although the R H process completely eliminates any rim zone, the superior cleanness of the ingot, due to lack of additions and drop in oxygen content during treatment, ensures that the surface zone of the degassed ingot is quite the equal of ordinary rimming steel. One table, thirteen figures, 21 references and an Appendix showing calculations of residence time for steel undergoing degasification. (Japan) M Hirase, Iron and Steel Institute Special Report No 92, November
1965, (in press). 37 : 53 866. Physical considerations in the stream degassing of steel. (Great
Britain) This paper deals exclusively with ladle-to-ladle stream degassing although it is agreed that for certain applications there are advantages in stream dcgassing direct into the mould. The mechanisms of bubble and droplet formation are discussed in connection with the removal of hydrogen and oxygen in particular. Heat losses in 120 and 8 ton plants are considered with regard to methods of reducing them, There is one table, one figure, seven references and an Appendix showing the theoretical calculations for removal of hydrogen in stream degassing in which it is shown that droplets