D.C.: 621.762.5

Key words:refractory ceramic materials, sintering, tunnel kiln, heating zone, sintering zone

Avram   Nicolae,    Maria   Nicolae,  Gheorghe G.  Calea, Neculai Murguleţ  , Vasile Luca:Calculationrelationshipsrequired forcharacterization ofthermalprocessesduringceramicmixturessintering

Metalurgia (55) 2003, nr.7, p.5

Thermal processes developed in tunnel kilns for refractory bricks sintering arecarried onin three specific zones: heating, firing (sintering) and cooling. Investigations performed by the authors, regarding calculations relationships required for obtaining specific time required for working zones of tunnel kiln, are presented in this paper.

D.C.: 669.094.3;621.794.61;

Key word:steel reoxidation, bubbles absorbtion, mathematic model, laboratory experiments

Lucian Cotor, Constantin Bratu:Steelreoxidationwithatmosphericoxygenduringtapping

Metalurgia (55) 2003, nr.7, p.10

The researches of the last years approached the steel reoxidation by atmospheric air, considering that the oxygen enter into steel by bubbles absorbtion in the metallic bath.

               The present paper studied on industrial flow a number of 38 aluminium killed heats, having different compositions. The heats were elaborated in a BOF blowing converter of 180 tons capacity, totally automated. A series of conclusions could be observed, the most important being that the steel reoxidation could develop following a model like: having in mind that the oxygen absorbtion took place in the plunge area, here is created due to the adition method of ferro-alloys control, the optimum conditions for absorbtion by appearing a well deoxidated area of steel, with a high capacity to capture the oxigen. These areas are alternatively created – oxidated area/deoxidated area - the summ of oxygen quantities which results in oxidated areas generating the high values observed.

               Anyway, due to the difficulties to establish a mathematic model based on the experiments made on the industrial flow, it is necessary to be conducted laboratory experiments in order to confirm this model.

D.C.: 669.13;681.3

Nicolae Constantin, Diana Ioniţă, Augustin Semenescu, Cristian Viorel Semenescu, Mircea Costache:Optimisationofironmaking bycomputerassistedprocesscontrol inblastfurnaces.PartI.Mathematicalmodelperformance,required forcomputerassistedprocesscontrol inblastfurnaces.Softwareapplication „Blastfurnacecalculation”performance

Metalurgia (55) 2003, nr.7, p.17

The mathematical model presented in this scientifical research paper can be used for the computerized leading of all processes that are developed in the blast furnace in case of using varied auxiliary combustibles.

               For this reason, first of al it is made the process simulation using this model. By the process simulation there are obtained results that can be confirmed by the blast furnace real function. In certain real situations, the results of the mathematical model are not total confirmed, in thatcase the model's equations must being improved by adoption at the real pig iron conditions(there are introduced the corrections index).

               It is obtained a mathematical model that shows with fidelity the unfoldement of all the processes from inside the blast furnace. It can be obtained the computerized leading

 of the cast iron making in the same time it can be obtained small material and energetical consumption.

D.C.: 621.762.5

Daniela Florentina Tărâţă:Theexperience of aresearch-producingactivity, insmallseries, of someparts ofsinteredpowders

Metalurgia (55) 2003, nr.7, p.29

The results of microproduction unit, working at Craiova-University using powder metallurgy processes are shortly presented in the paper.

The rezults were obtained in the period 1995-2002.

D.C.: 539.214;666.3

Key words:superplasticity, strain rate, strain rate sensibility,flow stress

Rus Ana – Luciana:Superplasticity ofceramicmaterials

Metalurgia (55) 2003, nr.7, p.33

Unlike superplastic metals, the observations of superplastic flow in ceramic materials are very recent. The first demonstration had been made by Wakai and his co- workers in a polycrystalline yttria (Y-TPZ) and than the researches had been continuiting on different monolithic ceramics and ceramic composites.The paper present the advance of research regarding the superplastic behoviour of ceramic materials, the classification of these, the mechanical proprieties and the grain boundary structure, for understanding the mechanism of superplastic deformation .

D.C.: 539.319

Key words:elasto-plastic field, residual stresses, finite-element method, numerical analysis, plane modeling, spatial modeling, strains gauges

Nicolae Bal, Mircea Bejan:Thenumerical andexperimentalstudy of theresidualstresses in thebowls

Metalurgia (55) 2003, nr.7, p.39

The paper presents aspects concerning the bending of the sheets in the elasto-plastic field. Just below is realized a comparative study between the residual stresses values obtained by the numerical calculus (plane modeling, spatial modeling), analytical method and experimental testing.

D.C.: 669.65.015

Denis Suraki:Arguments forrussian-romaniancooperationdevelopment in theiron andsteelindustrialfield

Metalurgia (55) 2003, nr.7, p.45

The paper asserts the necessity to develop partnership andcolaborationin the iron and steel industrial field, betweenRomaniaandRussian Federation.

The tradition in this field, the situation of worldwide iron and steel industry, transition to the market economy, trading flow, last mergers, all are arguments to support the development of this cooperation.