Nondestructive inspection of the quality of fused and cast baddeleyite-corundum refractories

Abstract

Fused and castbaddeleyite--coruudumrefractories are characterized by chemical and phase inhomogeneity [1][2][3], which has a significant influence on the stable operation of glass melting furnaces and the quality of the glass.The zonality of the structure of the electrically melted refractories is the main factor preventing the production of parts with stable physicOtechnical properties.Earlier [4] the possibility was established of inspection of the macrostructure of baddeleyite--corundum refractories by a radiowave method. X-ray and ultrasonic methods are promising for evaluation of the local inhomogeneity of the macrostructure of large block refractories.This article presents certain data on the development of nondestructive testing of BKCh-33 fused and cast industrial refractories produced by Podol'sk Refractory Part Plant by the ultrasonic method.According to existing technical documentation [5] the quality indices of electrofused refractories are the chemical composition and the apparent density by measurement pm mwhere pm is the apparent density by measurement, m is the weight of the part, and V is the ap volume calculated from the external geometric dimensions without taking into consideration voids in the part and the curvature of its faces. Distribution parameters * of the apparent 'art Part dimen-Total ~o.. sions, mm number density by. measurement of parrs I a,.m_3 ..10_,[ R~_Rm,x mode~ien asym. excess I 600X 300X250 3,60 2,54 I 5~4 3,47--3,76 I 3,59 | 3,60 0,026 ] --0,022 2 600>~400X250 3,57 3,52 [ 5,93 3,40--3,68 I 3,56 [ 3,58 --0,630 1 0,132 3 3,59 3,08 [ 5,55 3,44--3,73 [ 3,61 l 3,60 [ --0,378 [ --0,132 6 3,76 15,6 3,40--3,99

Heat resistance of fused and cast baddeleyite-corundum refractories

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666.762.52.017:536.495 and V. V. Kolomeitsev Refractory materials of the Al20~--Zr02--SiO2 system are widely used in glass melting and the steel industry [1][2][3][4][5].Extensive domestic and foreign literature [1][2][3][4][5][6][7][8][9] has been devoted to questions of the technology and investigation of the physicotechnical properties of Al2Os--Zr02--SiO2 systembased fused and cast refractories but publications on the heat resistance are limited and contradictory [i, 4]. The heat resistance of these materials is determined by the heating--cooling cycle method, which does not make it possible to reliably evaluate the allowable heating (cooling) rates of parts and the limiting destructive heat flows under actual service conditions.

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“…The heat resistance of these materials is determined by the heating--cooling cycle method, which does not make it possible to reliably evaluate the allowable heating (cooling) rates of parts and the limiting destructive heat flows under actual service conditions. Also contradictory is data on the influence of texture and microstructure of the material on the heat resistance of baddeleyite--corundum parts.There exists an opinion [4] that the material of the coarse-grained and porous zones of parts will have a higher heat resistance than the material of the dense zone.This article presents certain results of investigation of the heat resistance of BKCh-33 baddeleyite--corundum parts.The indices of the physicomechanical properties and heat resistance were determined on specimens (hollow rings and solid cylinders and prisms) cut from various zones of production parts in accordance with the classification of zones adopted in [6]. The heat resistance was determined from the calculated values of the criteria R and R' [7] and experimentally.…”