V. M. Yam

Production of refractory parts by electrohydroimpulse pressing with preliminary vibroforming

ConclusionsThe Investigations conducted showed that a combined method including vibroforming of parts with subsequent electrohydroimpulse pressing makes it possible to obtain from lowplasticity powders of corundum and alumina parts with high density, strength, and other improved physicomechanical characteristics.

Vibration molding of chamotte products of complex shapes

ConclusionsVibration molding makes the mechanization of the manufacture of chamotte products of complex shape possible with the result that labor productivity increases, the drying process is simplified, the working conditions are improved and the product quality is better.

Magnesia nozzles for high-speed steelcasting produced by vibropressure molding

ConclusionsThe article describes the design development of steelcasting nozzles with a channel diameter of 120 mm and the development of the production technology for these nozzles. With these nozzles the stopper and batching device functions efficiently during the casting of rimmed and semikilled steel. The configuration and diameter of the nozzle channel undergo no changes in the process.The increase in the channel diameter from 100 to 120 mm results in the average linear speed at which the ingot mold is filled increasing from 3.8 to 5.2 m/min; in a decrease by 32% in the pouring time per melt (from 25 to 17 min) so that the work load on the cranes is reduced and the handling capacity of the casting bay is increased; in a 15% increase in the durability of the ladle lining which gives a saving of 100,000 rubles/yr as a result of lower refractories consumption; and in less spoilage of billets and strip steel.The end result is that the net cost of the rolled product decreases by 0.35 ruble/ton.

Trough of polycrystalline silicon carbide for electric soaking pits

ConclusionsThe results of laboratory investigations and tests under industrial conditions demonstrated that in principle it is possible to use MPC as material for trough sections for electrically heated soaking pits.

Vibro-molding of refractory compounds

ConclusionsThe advantages of vibro-molding lie in the fact that the density and strength of the product are high, the properties are evenly distributed throughout the product, the grain size distribution is not affected, and a high-grade grog product can be molded from a compound containing a large proportion of fine particle fraction.The weight of vibro-molding plant is less than that of standard molding plant giving the same degree of product density.The vibro-molded product is more durable than the standard-molded one.

Vibroimpact forming of tarred converter refractories

ConclusionsUsing experimental vibroimpact equipment in production conditions studies were made of the vibroimpaet molding of tarred dolomite-magnesite converter refractories.Vibroconsolidation yields tar-containing dolomite-magnesite refractories at pressures of 1 kg/cm2 with much improved quality factors (density, homogeneity, strength), and also a much higher (by about one order) hydration resistance, than pressing at 1300 kg/cm2.The density of the vibromolded products is greatly affected by the quantity of tar in the body and its temperature. The quantity of tar added should be not less than 5.5%, and the body temperature 90–100°.To achieve a density in tarred dolomite-magnesite products by vibromolding, corresponding to the technical specifications, a process time of 30 sec is quite sufficient.

Vibration equipment for making refractories

ConclusionsA design was developed for an industrial vibroimpact installation for making refractories. The equipment has been introduced into production. A series of measures were studied and introduced, leading to increases in the working reliability of the vibration equipment, sharply reducing the noise level, increasing the effectiveness of densification, and reducing the transmission of oscillations from the foundation of the vibration equipment to the surrounding elements of the building.The production of various shapes and large silicon carbide products weighing up to 40 kg was developed in production conditions.

Vibroimpact molding of large silicon carbide shapes

ConclusionsVibroimpact compaction methods were used to prepare large complicated shapes which in terms of quality (density and variations in density) are better than those made by tamping.Vibroimpact densification is a mechanized and more productive method of molding large complicated shapes than the currently used tamping method.

Industrial development of vibroimpact molding of silicon carbide refractories

ConclusionsA technology was developed for the vibrocompaction of silicon carbide refractories. The efficiency of the process was confirmed in industrial conditions.The properties achieved by vibrocompaction in silicon carbide refractories and their uniformity of distribution appreciably exceeds similar characteristics for tamped, and to some extent pressed, refractories.Vibromolding equipment is very simple in design, of low metal content, low power rating and cost, and can be used to obtain product qualities at pressures of 1–2 kg/cm2 that are achieved in pressing only by pressures of about 1500 kg/cm2.The use of vibrocompacted silicon carbide slabs in the porcelain industry as kiln furniture increased the inter-repair periods for shelf cars for firing pottery.

Density of semidry silicon carbide bodies made by vibroimpact compaction

ConclusionsOther conditions being equal, the process time for compaction depends on the excitation force and the contact compression pressure. For each value of excitation force there exists a definite optimum contact pressure, up to which there is a gradual increase in the final density of the material and a reduction in the required vibration time. An increase in the contact pressure above this optimum value causes a reduction in the final density and an increase in the compaction time.