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Metalurgia INTERNATIONAL English version, published by romanian metallurgical foundation Honorary president of scientific publishing house f.m.r. Dr. ec. Lepădatu v. gheorghe vol. X (2005) no.5 romanian metallurgical foundation Scientific publishing house

romanian metallurgical foundation Scientific publishing house scientific board staff Professor NICOLAE AVRAM Ph. D. professor Scorţea Costin Ph. D Managing Director: Professor Scorţea Costin Ph. D. Editor-in-chief: Professor Nicolae Avram Ph. D. Professor Maria Nicolae Ph. D editorial board: Prof. dr. eng. bejan Mircea Prof. dr. eng. bunea Daniel Prof. dr. eng. cănănău nicolae Prof. dr. eng. GEORGETA COŞMELEAŢĂ Prof. dr. eng. CIUCĂ ION Prof. dr. eng. gaba aurel Prof. dr. eng. GĂLUŞCĂ DAN GELU Prof. dr. eng. hepuţ teodor Prof. dr. eng. IONIŢĂ GHEORGHE Prof. dr. eng. mănescu tiberiu Conf.dr. eng. TODERIŢA NEMEŞ Prof. dr. eng. samoilă Corneliu Prof. dr. eng. SCORŢEA COSTIN Prof. dr. eng. SIMITI IOAN VIDA Prof. dr. eng. SOFONEA GALAFTION Prof. dr. eng. Şaban Rami Manager Scientific Publishing House F.M.R.: eng. Florentina Brânduşa Scorţea

Contents Issn 1582 – 2214 Ciobanu Ioan, Munteanu Sorin Ion, Crişan Aurel, Maşniţă Mihai: 3D Mathematical model to simulate the macro-solidification of castings from eutectic alloys .. 3 Ghimbăşeanu Ioan: Experimental system of measurement and determination of a semiconductor material resistance ……………………………...……………….. 12 Potecaşu Octavian, Florentina Potecaşu: Electro conducting composites with components arranged in coils ……………………………………………………. 16 ALEXA Vasile, Raţiu A. Sorin, KISS I. Imre: Theoretical and experimental analysis of the rolling strain in the deformation area ……………………………………... 20 Chichernea Florin: Comparative study on static breaking of cast steel part shrink heads-third chapter ………..… 29 Ana JOSAN: Studies and researches concerning the operational behavior of steel cast rolling rolls ……………………. 35 Ermina ŢAPU, Elena DRAGULĂNESCU, Nicoleta-liliana frăţilă: Algorithms used for 3d form show ……… 42 ? international calendar of conferences…….….……. I - III ? Press release ……………..…………...................... IV - VIII ? New books, published by romanian metallurgical foundation ………………………………..…..….…….. IX - X

abstract

metalurgia International 5/2005

D.C.: 621.746.62 Keywords: mathematical model, solidification Ciobanu Ioan, Munteanu Sorin Ion, Crişan Aurel, Maşniţă Mihai: 3D Mathematical model to simulate the macro-Solidification of castings from eutectic alloys Metalurgia International (vol. X), no.5, 2005, p. 3 The paper presents a mathematical model and a 3D software for the solidification simulation of casting purred from eutectic alloys. There are presented the hypothesis that lay on the basis of the mathematical model. The model uses the finite differences method applied to finite elements of box shape. There are presented the mathematical equations that form the mathematical model and their usage in the software. The mathematical model is based on the thermal balance equation for an elementary time interval and for a box element The thermal balance equation was particularized for 9 situations so obtaining the equation that constitute the basis of the mathematical model. There are presented two the software structure and the possibilities of using this software during the research about the solidification of castings with complex geometry purred by eutectic alloys. D.C.: 621.315.592; 537.311.31 Ghimbăşeanu Ioan: Experimental system of measurement and determination of a semiconductor material resistance Metalurgia International (vol. X), no.5, 2005, p. 12 The semi-conductor material we analyse in this paper has a sensibly thermo resistance. The semi-conductor material is made up of sintherized mixtures of metal oxides, such as manganese, iron, cobalt, nickel, copper. The method we use in order to determine the resistance of the semi-conductor material is a modern method of data acquiring designed within the LabVIEW programme that uses LabJack U12 acquisition plate. D.C.: 669.018.25 Potecaşu Octavian, Florentina Potecaşu: Electro conducting composites with components arranged in coils Metalurgia International (vol. X), no.5, 2005, p.16 The paper describes the experiments carried out on electrical conductors made from lamellar-oriented Al- Cu composites with Cu percentage up to 20%. The mechanical resistance and electrical resistivity have been measured on conductors of three different deformation and final diameters of 4, 5, 6 and 8 mm.

D.C.: 539.371 Keywords: rolling strain, deformation area, theoretically and experimental analysis ALEXA Vasile, Raţiu A. Sorin, KISS I. Imre: Theoretical and experimental analysis of the rolling strain in the deformation area Metalurgia International (vol. X), no.5, 2005, p. 20 The paper introduces the deformation areas during uneven rolling of metal and the mean rolling strain in that area, making use of information from the actual theory of calculating strain in the deformation area and also gives the results of laboratory. D.C.: 621.746.464.; 539.4.011 Keywords: modelling, the static break, running, feeding, cast steel. Chichernea Florin: Comparative study on static breaking of cast steel part shrink heads-third chapter Metalurgia International (vol. X), no.5, 2005, p. 29 In the laboratories of the Materials Science and Engineering Faculty of the Transilvania University of Brasov a number of theoretical and experimental studies have been conducted on the 3D – modelling of part casting with gatings and shrink heads, as well as on the modelling of breaking generating strains. D.C.: 621.771.07; Keywords: durability, hardness, Adamite steel, rolling cylinders Ana JOSAN: Studies and researches concerning the operational behavior of steel cast rolling rolls Metalurgia International (vol.X), no.5, 2005, p. 35 This paper presents a critical analysis of the operational behaviour of Adamit steel cast rolling rolls. It presents some data recorded during the industrial practice at the Middle Profile Rolling Train of the S.C. “Siderurgica S.A. Hunedoara. Some measures are suggested for increasing the rolling cylinders’ durability figures, having a direct influence on the company’s expenses. Keywords: Algorithms, visibility, coherent, area, hide areas, scanning Ermina ŢAPU, Elena DRAGULĂNESCU, Nicoleta-liliana frăţilă: Algorithms used for 3d form show Metalurgia International (vol.X), no.5, 2005, p. 42 In this paper, we will talk about shadow algorithms and randomize technique, used for texture introduction. The problems about visibility frequents are named “lines hide or area hide”.