A new design of electron beam gun for welding in open space has been developed. The gun design is based on the application of triode emission system with improved quality of electron beam formation. This provides increased specific power of the beam and, as a result, the high capability to increase the penetration depth of welded joints. To reduce the dimensions of the gun and increase its service reliability, the high-voltage insulation has been provided applying metal-ceramic heat-resistant welded-brazed vacuum-tight components. The original technologies for their manufacture have been developed. The performed tests of the new gun design have proved the possibility of its application under open space conditions.
We have a great honor to work together with academician Borys Evgenovych Paton, who by his selfless labor made great contributions to the restructuring of the Academy of Sciences of Ukraine, founded in 1918 by the initiative of Volodymyr Ivanovych Vernadsky, the famous scientist and public figure. During the years of its activity the Academy attained great achievements in many fields of science and technology. Numerous discoveries and inventions were made, many theories and conceptions were put forward, scientific and technical directions were started, the world-known scientific schools were organized, to which the Paton school belongs, which educated and united the scientists in the field of electric welding and related technologies, materials science and metallurgy. All the labor life of Borys Paton is inseparably connected with the Institute of Electric Welding. This is the call of «technical nature», family tradition and son's duty to continue the father's activity. The talent of the famous scientist with a wide sphere of interests was especially pronounced in Borys E. Paton at the post of the Institute director. To define clearly the purpose of investigation, to forecast the most important link in it, to attract interest of a large team of scientists to the new direction are the main tasks of the scientific leader, which were successfully realized by him showing the self ability to work with the team, readiness in supporting of any interesting idea, to assess worthy the fulfilled work. His inexhaustible enthusiasm, unique working ability and respect of each staff member provided the healthy creative atmosphere in the working staff. Over 65 years the work of the Institute under the leadership of Borys E. Paton is the wonderful continuation and implementation of profound and challenging principles of scientific-technical activity of Evgen Oscarovych Paton, the founder of our Institute. The scientific-technical directions, started by Borys Paton, widened greatly the subjects of studies and developments. The purposeful fundamental studies, started at the Institute, became the theoretical bases of welding science, transforming it into powerful means of technical progress, that led to the revolutionary changes in many branches of industry, such as: machine-, ship-and aircraft building, aerospace industry, power engineering, railway transport, mining complexes, metallurgy and chemical production, promoted the creation of pipeline transport, construction industry. Many scientific developments predetermined the world development of welding technologies and went down in history of the science and technology progress. The world authority of B.E. Paton came by comprehensive and fruitful scientific and engineering activity, desire to direct the fundamental research to the solution of actual problems of the scientific-technical progress. By his contributions he made grounds of arc welding, namely the theory of the automatic machines for arc welding, which further was improved by many specialists in the field of the automa...
One way of extending the raw materials base of the refractories industry is to use certain slags from the iron and steel industry [i]. Of great practical interest for the mass production of fused refractories based on forsterite-spinel composition are magnesia--silicate slags formed during the smelting of ferrochromium in ore-thermic furnaces in a number of ferroalloy factories. The output of slags is about 400,000 tons a year, and there is a tendency to increase this output [2].These slags are formed as a result of carbon-thermic reduction of chromium ores; therefore, in contrast to other metallurgical slags containing calcium oxides, the slags of carbon and cast iron ferrochromium-magnesia slags have their CaO in the form of impurity. Slags contain* 28--36% Si02, 35--50% MgO, 15--25% AI2Os, 2--8% Cr2Os. Impurities of CaO and FeO are present, as a rule, in amounts of not more than 2 and 1%, respectively. The total of three components (MgO, Si02, and AI2Oa) in the slags is 90-95%. On the phase diagram for the system MgO--AI2Oa--Si02 the slag compositions lie in the field of crystallization for forsterite and spinel (Fig. i).Slag melt after discharge from the furnace crystallizes, and is cooled in the slaggers; after cooling it consists of a stony mass with coarsely crystalline structure. The phase composition of the slags from the cast iron and carbon meltings consists of forsterite, spinel, and siliceous glass enriched with oxides of calcium, aluminum, chromium, and iron. Depending on the chemical composition and cooling rate (central or peripheral part of the ingot) the amount of glass may vary from 10-15 to 30-40%. With a reduction in the melt in the MgO/Si02 ratio, enstatite in addition to glass is formed. The chromium oxide is present as aluminochrome spinel. Magnesium and calcium aluminosilicates crystallize in small amounts in the intermediate substance; these are cordierite, augite, and montichellite, for example. The slags contain buttons of ferrochromium. Figure 2 shows the typical microstructure of the original slag for cast ferrochromium melting.The melting temperature of the slags is 1630-1670aC. The siliceous glass phase markedly reduces their refractory properties. Anegative influence on the refractory is also exerted by the metal remaining in the slag. In the German Democratic Republic it is proposed to use slag as the fused "grain" with finely milled magnesite bond to obtain sintered forsterite refractories [3]. Research has been carried out with the use of dump slag as fillers for heat-resistant concretes, but the refractory properties of the resulting concretes were poor [4]. At present slags from cast iron and carbon ferrochromium smelting are hardly used, and are taken to dump in the form of ingots. A marked improvement and stabilization in their compositions and refractory properties are necessary for their use.An improvement in the refractory properties of these slags, as follows from the phase diagrams, should occur by increasing their concentrations of MgO, Al2Oa, and Cr20a (separately or...
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