The grinding tool does not have a solid cutting edge, in most cases the front angles for abrasive grains are negative, the grains have rounded vertices and an irregular geometric shape. Grinding ...should be considered as a process of cutting-scratching the surface layer of wood with a large number of abrasive grains of the grinding tool. The main purpose of the grinding process is to prepare the surface for finishing by eliminating irregularities and defects of the previous processing. The effectiveness of grinding to a greater extent depends on the processing conditions, characteristics and properties of the grinding tool. Theoretical studies and analysis of the derived equations for determining the critical values of the rake angle, cut thickness and cutting speed show that all of the above parameters have a significant effect on the amount of lifting of the processed material by abrasive grain and the intensity of the appearance of contact fractures. An increase in the critical thickness of the slice leads to an increase in the deformation of the surface layers of the processed material, and, consequently, to an increase in the depth and number of contact fractures. The increase in the absolute value of the rake angle leads to the need to increase the critical cutting speed to ensure the conditions of chip formation. In general, an increase in cutting speed always has a positive effect on chip formation conditions and on the quality of the machined surface. An increase in the modulus of the rake angle leads to a deterioration in the conditions of chip formation and surface quality. An increase in the radius of curvature of the cutting edge of the grain leads to an increase in the critical thickness of the slice, which entails an increase in contact deformations and fractures.
Grinding holds the specific place among other types of machining of wood caused by specific features of the occurring physical phenomena and features of the tool. When processing the mechanical, ...chemical, thermal, electric and accompanying those phenomena arise a multiple-point cutting tool of preparations from wood or wood materials, naturally. The mechanical phenomena are shown owing to repeated contact of an abrasive paper from the preparation processed by a surface, that is, the fissile sliding friction. These phenomena are followed by a pollution of a cutting tool, including consolidation of space between abrasive grains that reduces operability of an abrasive paper. On the basis of the conducted theoretical researches and the analysis of the removed equations for determination of critical sizes of front corner, thickness of cut and speed of cutting, it is possible to draw conclusion that all listed parameters have significant effect on the size of bearing of the processed material abrasive grain, therefore, and on intensity of emergence of contact collapses. Increase in critical thickness of a cut leads to increase in deformation of near-surface layers of the processed material, and, therefore, and to increase in depth and the number of contact destructions.
Results are provided for an experimental study of the effect of deoxidation on the composition of nonmetallic inclusions in pipe steels melted in a vacuum induction furnace with a periclase lining. ...Thermodynamic calculations are made for oxygen activity within melts with lanthanum, cerium, aluminum, and yttrium for the metal of four melts. Conditions are evaluated for magnesium spinel inclusion formation in relation to deoxidant used and the extent of deoxidation. The effect is demonstrated of reduced aluminum concentration during metal ladle treatment on nonmetallic inclusion composition and the possibility of modifying them in the course of an industrial pipe steel melt.
FactSage
TM
software is used successfully in the Gruppa Magnezit engineering section making it possible to calculate thermodynamic equilibria in multicomponent systems, to construct phase diagrams, ...and to calculate viscosity in molten slags and glasses, etc. Use of specialized software makes it possible to both analyze premature wear of linings, and also the preliminary selection of refractory compositions, slag modifiers or directly for slag regimes optimum from the point of view of fulfilling metallurgical tasks and reducing refractory specific consumption. Modeling results are provided for processes occurring within ferrous and nonferrous metallurgy units.
Thermodynamic modeling is provided for nonmetallic inclusion formation during extra-furnace treatment and solidification of low-alloy low-carbon steels intended for use in corrosion-active media. ...Relationships are established for the effect on inclusion composition of alloying element additives, a periclase lining, calcium-containing materials, and presence of sulfur within a melt. Conditions are determined for a reduction in the amount of corrosion-active nonmetallic inclusions.
Ladle-treatment slags are primary wastes from steel production. Slag utilization is prevented by its spontaneous decomposition as a result of polymorphic transformation of dicalcium silicate with ...decrease in slag temperature. At OOO NLMK-Kaluga, the slag is stabilized by the introduction of boron oxide in the high–magnesia flux during ladle treatment. Industrial tests indicate stabilization of the slag and the formation of a protective layer on the lining, preventing slag corrosion.
FactSage.sup.TM software is used successfully in the Gruppa Magnezit engineering section making it possible to calculate thermodynamic equilibria in multicomponent systems, to construct phase ...diagrams, and to calculate viscosity in molten slags and glasses, etc. Use of specialized software makes it possible to both analyze premature wear of linings, and also the preliminary selection of refractory compositions, slag modifiers or directly for slag regimes optimum from the point of view of fulfilling metallurgical tasks and reducing refractory specific consumption. Modeling results are provided for processes occurring within ferrous and nonferrous metallurgy units.
A burned magnesium-lime flux is designed. It makes it possible to solve the problem of increasing the resistance of an arc steel-melting furnace (ASF) lining via the formation of a high-magnesium ...slag and the appearance of a slag skull on the furnace lining.
The study described in this article had the goal of maintaining the temperature of a slab on the receiving and intermediate conveyors of a rolling mill and also maintaining the temperature of the ...resulting strip before it leaves the finishing train. This is achieved by applying a protective coating to the slab before it is charged into the heating furnace and after it leaves the last stand of the roughing train. The coating maintains the temperature of the metal after it leaves the furnace and moves along the receiving conveyor to the stands of the mill. It also prevents the formation of air scale on the slab surface. When plates are being rolled, use of the protective coating makes it possible to reduce the temperature to which the slabs are heated prior to rolling.
It has been shown that a new out-of-furnace treatment complex can be used in the open-hearth shop of the Vyksa Metallurgical Plant to make wheel steel that fully satisfies the existing requirements ...of the Russian Ministry of Railroads. The improved technology is distinguished by lower consumption indices due to the conservation of ferroalloys and alloying materials, shortening of the treatment, and stabilization of the conditions under which it is administered. Use of the technology makes it possible to obtain metal that meets present-day standards on product quality.
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