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306. Electron beam furnace
136
Classified Abstracts 303--308 37
303. Cold retort vacuum furnace. (Great Britain) The Engineer, 216 (5624), Nov. 8, 1963, 782. 37
304. Mass spectrometer checks welds. (U.S.A.) Anon., Iron Age, 193 (5), Jan. 30, 1964, 98-99. 37
305. Vacuum melting goes automatic. (U.S.A.) Anon., Iron Age, 193 (3), Jan. 16 1964, 80. 37 : 53
306. Electron beam furnace.
(Great Britain)
During the past fifteen years there have been considerable developments in vacuum metallurgy. One recent introduction in the U.S.A. and in Germany has been the electron beam furnace which is claimed to be superior to vacuum arc furnaces in certain respects. Such furnaces have been developed with ratings of up to 1500 kW. In American designs t h e cathode surrou~ads the material to be melted concentrically but flash-overs are likely to occur with this arrangement whenever gas is released in appreciable quantities from the melt. An important improvement avoids this trouble by using the principle of the " remote cathode ". In the East German design described, the electron source is placed in a separate vacuum tank and the electron beam passes to the main tank through pumped intermediate chambers. A prototype 200 kW furnace using this principle is described. The main chamber, in which the melting takes place, is evacuated by a 25,000 1./sec oil diffusion pump backed by a 350 m3/hr mechanical pump. In addition, a 3500 m3/hr Roots pump is used for the preliminary evacuation. The chamber containing the electron gun, and [he intermediate chambers, are each pumped by a 500 1./sec oil diffusion pump. The minimum working pressure of 10 -5 torr in the melting chamber
can rise to 10-2 torr during the release of bursts of gas, or to 10 -3 torr continuously, without the disturbance reaching the gun. The single diode electron gun operates at 27 kV, 7.5 A (200 kW) and magnetic focussing is used to confine the beam to the narrow path through the holes between the various chambers. The article gives details of the mechanical arrangements for feeding in the material to be melted and for withdrawing the mould in which the casting takes place. The furnace has been used to re-melt bars and is capable of handling ingots up to 23 cm dia. and 1.4 m long weighing 450 kg. Evacuation of the furnace takes 30 to 60 min. It is claimed that an almost completely slag-free high-chrome steel can be produced by this method. The impact strength is raised from 1 k p m / m m ~ to 30 k p m / m m ~. Ball-bearings fabricated from this steel have a life of about 50 times that of ordinary ball bearings. (Germany) J. r~.
The Engineer, 216 (5624), Nov. 8 1963, 789-790. Experimental high-temperature X-ray diffraction furnace.
37 See
Abstr. No. 295.
38.
Distillation, Organic Chemistry, Isotopic Gas Analysis 38
307. A study of polynuclear aromatic hydrocarbons using the vacuum spark mass spectrograph. (U.S.A.) F. N. Hodgson, M. Desjardins, W. L. Baun, J. Phys. Chem., 67, June 1963, 1250-1253. 38 : 54 308. Cod liver oil refinery. (Gre~t Britain) The Engineer, 216 (5624), Nov. 8 1963, 774-775.
Classified Abstracts 303--308 37
303. Cold retort vacuum furnace. (Great Britain) The Engineer, 216 (5624), Nov. 8, 1963, 782. 37
304. Mass spectrometer checks welds. (U.S.A.) Anon., Iron Age, 193 (5), Jan. 30, 1964, 98-99. 37
305. Vacuum melting goes automatic. (U.S.A.) Anon., Iron Age, 193 (3), Jan. 16 1964, 80. 37 : 53
306. Electron beam furnace.
(Great Britain)
During the past fifteen years there have been considerable developments in vacuum metallurgy. One recent introduction in the U.S.A. and in Germany has been the electron beam furnace which is claimed to be superior to vacuum arc furnaces in certain respects. Such furnaces have been developed with ratings of up to 1500 kW. In American designs t h e cathode surrou~ads the material to be melted concentrically but flash-overs are likely to occur with this arrangement whenever gas is released in appreciable quantities from the melt. An important improvement avoids this trouble by using the principle of the " remote cathode ". In the East German design described, the electron source is placed in a separate vacuum tank and the electron beam passes to the main tank through pumped intermediate chambers. A prototype 200 kW furnace using this principle is described. The main chamber, in which the melting takes place, is evacuated by a 25,000 1./sec oil diffusion pump backed by a 350 m3/hr mechanical pump. In addition, a 3500 m3/hr Roots pump is used for the preliminary evacuation. The chamber containing the electron gun, and [he intermediate chambers, are each pumped by a 500 1./sec oil diffusion pump. The minimum working pressure of 10 -5 torr in the melting chamber
can rise to 10-2 torr during the release of bursts of gas, or to 10 -3 torr continuously, without the disturbance reaching the gun. The single diode electron gun operates at 27 kV, 7.5 A (200 kW) and magnetic focussing is used to confine the beam to the narrow path through the holes between the various chambers. The article gives details of the mechanical arrangements for feeding in the material to be melted and for withdrawing the mould in which the casting takes place. The furnace has been used to re-melt bars and is capable of handling ingots up to 23 cm dia. and 1.4 m long weighing 450 kg. Evacuation of the furnace takes 30 to 60 min. It is claimed that an almost completely slag-free high-chrome steel can be produced by this method. The impact strength is raised from 1 k p m / m m ~ to 30 k p m / m m ~. Ball-bearings fabricated from this steel have a life of about 50 times that of ordinary ball bearings. (Germany) J. r~.
The Engineer, 216 (5624), Nov. 8 1963, 789-790. Experimental high-temperature X-ray diffraction furnace.
37 See
Abstr. No. 295.
38.
Distillation, Organic Chemistry, Isotopic Gas Analysis 38
307. A study of polynuclear aromatic hydrocarbons using the vacuum spark mass spectrograph. (U.S.A.) F. N. Hodgson, M. Desjardins, W. L. Baun, J. Phys. Chem., 67, June 1963, 1250-1253. 38 : 54 308. Cod liver oil refinery. (Gre~t Britain) The Engineer, 216 (5624), Nov. 8 1963, 774-775.