Monolithic linings in steel ladles wear out because of several factors: thermal, chemical, and mechanical.Differences in ladle service conditions make it necessary to improve existing ramming compounds and develop new ones [1][2][3][4][5][6][7][8].The authors have developed a method of testing these linings in the ladle.Blocks made of sand-slung rammings were used. They were prepared on a sand-slinger ring based on model 296-M2 with a slinger-head diameter of 670 mm. The blocks are trapezoidal in shape and correspond to the outline of linings in the slag belt of a 150-ton steel ladle. The block dimensions in the upper part are 500 • 480 • 150 mm, in the lower 480 • 460 • 150 mm, and the height is 320 mm.Blocks were made of Chasov-Yar loamy sand grade PO-16 and lean river sand from the Kaidaksk port in Dnepropetrovsk.Graphite waste, chromite, and zircon were added to the Chasov-Yar sand ramming bodies with various amounts of DN-I clay to the river-sand body. Aqueous solutions of MgSO~-7H20, H3PO~, aluminochromophosphate (TU MKhP6-78-166-73) and sulfire lye were used as binders.Blocks were tested in the slag belt of 150-ton ladles in the Petrovskii open-hearth shop. The ladles were linked with KShU-39 firebrick.The steel-discharge temperature was 1610-1620~ the metal stayed 60-90 min in the ladle during casting, and the slag basicity was ].9-2.2.The average wear of Chasov-Yar sand blocks without additives was 10.2 mm for one pouring.Adding 15% chromite and 10% graphite waste to the Chasov-Yar sand reduced the resistance. When 30% zircon was added the average block, wear per pouring dropped from 10.2 to 8.0 mm. When solutions of MgSO4o7H20 and sulfite lye were used as binders, the resistance diminished. Using orthophosphoric acid and aluminochromophosphate did not markedly increase the resistance.Blocks based on Kaidaksk river sand showed much less wear in one pouring.Their resistance increased with a fall in added clay content, i.e., when the Na20 and K20 contents were reduced.Thus, a reduction in the alkalis from 1.28 to 0.35% reduced the block wear from 10.2 to 3.4 mm per pouring.Petrographic study of the blocks after service showed that they developed zone formation when a temperature gradient and molten slag and metal were present.* The least-changed zones in most specimens showed slight cracking and surface cristobalite formation of the quartz grains. As a result of interaction between silica and the impurities in the sand with the binder and under the temperature action, the least-changed zones formed a cryptocrystalline substance, which was less frequently glassy.Combustion of organic or carbonaceous constituents (when they were present) occurs in the transition zones, and in most cases the cryptocrystalline material is converted into glassy.There is some increase in the amount of metacristobalite in the quartz grains.The working zones are very dense, have an enhanced amount of glass in the bond, much cracking, and cristobalite formation in the quartz grains; the grain surfaces are covered, and the cracks fi...
The monolithic lining of steelcasting ladles is produced with a sand-slinger both in the Soviet Union and elsewhere from materials which consist mainly of quartz sand [1, 2]. The composition of Soviet quartz sand is variable and its content of fusing agents in the form of alkali increases the wear of the rammed lining in operational service. In recent times ladle linings of a mix of quartzite and refractory clay have been used with good results [3].
Owing to the widespread use of gate valves for steel casting, metallurgical factories are increasing their demands for highly resistant refractories. To satisfy these needs the Krasnogorovsk Factory, using experience of the Semiluksk Refractories Factory, has developed the production of corundum plates. The basis of the method is the use of corundum chamotte obtained by firing a mixture af alumina and kaolin at 1620-1640~The mixture af alumina and kaolin is milled in a tubemill to a content of nat more than 1% fractions plus 0.06 ram, and moistened with a water solution of sulfite lye to a water content of 15-18%. The briquet, about 50 mm thick, is prepared on a 4_KF-200 friction press using a rectangular mold. The apparent density of the briquet is at least 2.25 g/cm 3.To obtain stable properties and ensure an increase in the output of corundum goads, the plant has built and put into use a tunnel kiln especially for firing the briquet.The chamotte is crushed and milled sequentially in jaw crushers and in roller crushers, and then is subjected to magnetic separation and screened into fractions 2-0.5 and finer than 0.5mm. The finely milled constituent of the batch is prepared by grinding the chamotte fractions minus 0.5 mm, or alumina grade GK in a M-400 vibramill to a fraction content of not more than 1% plus 0.06 ram.Using alumina substantially reduces the demand for scarce chamotte fractions (--0.5 ram), and awing to the better grindabiHty of GK alumina there is an increase of about three times in the productivity of the vibromill.Originally the body was prepared in the I-A-H mixer runnermills by blending and moistening with a solution af sulfite lye to a water content of 3.5-4.4% corundum chamotte fractions 2-0.5 and --0.5 mm together with the finely milled constituent. However, pressing the goods showed that compounds prepared in these
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