V. E. Vernikovskii

Method of determining strength of green refractories

ConclusionsWe designed and built an attachment for apparatus of the level type for determining the strength of the edges of unfired ceramic specimens under compression and shear.As a result of the studies made on the modernized apparatus we established that the green freshly shaped specimens made from currently used and modified materials, using strengthening agents, molded under a pressure of up to 150 MPa, do not possess compressive strengths or crimping edge strengths required for the formation of multicourse setting of goods on kiln cars, as with the use of chrome-magnesite and chamotte goods.Since, during the drying and firing of chamotte and chrome-magnesite refractories, certain articles are subject to damage, especially in the lower courses, then to make it possible to change over to loading of freshly molded dinas green brick onto kiln cars, the compressive and crimping strengths should be not less than 6 and 0.6 MPa.

Pressing nozzles for high-speed steel teeming

ConclusionsThe Magnezit Combine has begun production of unfired pressed steel-teeming nozzles, with a channel diameter of 120 mm and height of 400 and 450 mm, made of magnesite paste.These nozzles have been put into service and adopted for high-speed top teeming of steel from a 330 ton ladle in the open-hearth shop of the KMW.

The neutral plane and the molding strokes in a floating mold

ConclusionsA procedure was developed for calculating the position of the neutral plane and the upper and lower motions when using a floating pressure mold.The calculations were carried out for a K150 type press. The calculated and experimental values of powder compaction were in satisfactory agreement.

Pressing refractories in multicompartment press molds

ConclusionsEquations of compression are proposed and a method developed for a graphic analytical calculation scheme for the height and density of green brick located under fabrication pressure and after ejection from each compartment of a double-compartment press mold on hydraulic and mechanical presses.Calculations are made for the special case with 10% differences in terms of density of filling in the adjacent compartments of the mold.The different density of filling in the multicompartment press molds on hydraulic and mechanical presses causes a spread for simultaneously pressed products, not only in terms of the apparent density but also in terms of the height. The discrepancy in the height of the products is due to the different values of the elastic deformations.

Determining pressing rates for refractory semidry bodies

ConclusionsAn inverse relationship was established for the permitted pressing rate and the ratio between the volume of the products and its double perimeter in plan. With an increase in the dimensions of the article it is necessary to reduce the pressing rate to exclude the formation of pressing cracks.Empirical equations are proposed which as a first approximation can be used for calculating the average rates and durations of pressing, and also for accumulating data connected with the question under discussion.

Performance of mixers at the Chasov Yar Refractories Combine

ConclusionsDuring the blending of bodies, containing a mixture of chamotte and clay ground in combination in tube mills, on mixers of four types used at the Chasov Yar Combine, the best pressed specimens were obtained when the bodies were worked on the centrifugal runnermills 115 M with normal rollers. Therefore, we do not recommend the removal from these mixers of factory-made rollers, although the mixers require improvement.The dispersed feeding of slip into the mixer reduces the quantity of coarse granules in the prepared bodies. In this case it is necessary to use replaceable tubes for periodic cleansing of the apertures or to ensure forced delivery of the slip with spattering across the surface of the body being mixed.

Experience with producing ladle and blast furnace brick with a change in pressing rates

ConclusionsA reduction in the pressing rate improves the factors of ladle and blast furnace refractories, since it affords the possibility of increasing the permissible upper limit for the pressing force, starting from the condition that there are no overpressing cracks.In order to obtain refractories with a low porosity it is desirable to prepare ladle and blast furnace brick with 5.0–5.5 pressings per minute with an average pressing rate of 9–11 mm/sec.

Determining pressing curves for industrial refractory bodies

ConclusionsThis article describes real pressing curves for the commonest semidry refractory bodies. The curves may be used by refractories production technologists and press designers. The mathematical relationship is established for pressing parameters and specific fabrication pressure, and the empirical pressing coefficients are worked out.The relative discrepancy between the values for the density of the green brick determined by calculation methods and from the experimental curves does not exceed 0.8%.

Preparing tar-dolomite bodies in the SMB-2000-PNM mixer

ConclusionsThe SMB-2000-PNM mixer with steam heating can be used for preparing hot tar-containing bodies.The radial gap between the blades and the reinforcing elements should be maintained at no less than 20 mm, and between face no more than 5 mm.Replaceable reinforcement elements should be made from manganese steel.When planning new models for the mixer it would be desirable to install an extending jack for supporting the lids of the discharge traps, and centralized feed of thick lubricant to the bearings,etc.

The operation of filling carriages during the charging of press molds used to make large blocks

ConclusionsVibration of the carriage has a positive influence on the filling of press molds and prevents sticking.Filling the molds with two carriages does not have a positive influence on the uniformity of filling density compared with one carriage. Filling of the molds for which the volume of a single carriage is inadequate should be done with two runs.