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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. XI (2006) no.1 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: Editor-in-chief: Professor Scorţea Costin Ph. D. editorial board: Prof. dr. eng. bejan Mircea Prof. dr. eng. cănănău nicolae Prof. dr. eng. GĂLUŞCĂ DAN GELU Prof. dr. eng. hepuţ teodor Prof. dr. eng. IONIŢĂ GHEORGHE Conf.dr. eng. TODERIŢA NEMEŞ Prof. dr. eng. MARIA NICOLAE Prof. dr. ing. Ripoşan Iulian 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 Agop Marcel, Mamut Eden, Găluşcă Dan-Gelu, Ioniţă Iulian, Vizureanu Petrică: a theoretical approach of the heat transfer in nanofluids ……………………...……. 3 Nussbaum Adrian-Iacob, Carmen Hărău, Raţiu Sorin, Ilca Ioan: Analysis of some influences upon the force’s parameters and the quality of the rolled steels .................................. 22 Amalia Ana DASCĂL, MAKSAY Ştefan, Camelia PINCA-BRETOTEAN, HEPUŢ Teodor: Numerical researches on the optimalization of the chemical composition for OLT 35K steel with a view to obtaining superior mechanical features at high temperature ……..…… 28 Corneliu Stănăşilă, Constantin Nicolae, Stănăşilă Octavian, Toşcuţă Dragoş: New technology of coal’s drying .. 34 Catangiu Adrian, Ioniţă Gheorghe, Graţiela Petrişor: Characterisation of glass/epoxy composite laminates in uniaxial loading ............................................................................. 39 ? Press release ……………..……………………...….……...................... I – II ? Authors Index (2005) ………………………………………….…….. III - IV ? New books, published by romanian metallurgical foundation……. V - VI

abstract

metalurgia International 1/2006

D.C.: 66.015.24 key words: nanofluids Agop Marcel, Mamut Eden, Găluşcă Dan-Gelu, Ioniţă Iulian, Vizureanu Petrică: a theoretical approach of the heat transfer in nanofluids Metalurgia International (vol. XI), no.1, 2006, p. 3 A theoretical approach of the heat transport in nanofluid using the scale relativity is elaborated. In such context, one shows that the nP/L interface self-structurates as a non-linear Toda vortex lattice and one specifies some of its properties (intrinsic anisotropy and the phononic spectrum components). In our opinion, the heat transfer in nanofluid is given by means of the “thermal anyons”. D.C.: 621.771 Nussbaum Adrian-Iacob, Carmen Hărău, Raţiu Sorin, Ilca Ioan: Analysis of some influences upon the force’s parameters and the quality of the rolled steels Metalurgia International (vol. XI), no.1, 2006, p. 22 The research aimed at finding solutions for the ferrite dissolution in the structural matrix of steel and the improvement in deformability. The results allowed the optimisation of the technology by reducing the heating-up duration, and by dissoluting and globulising the ferrite. D.C.: 539.4/.5 Keywords: experimental testing, thermal-resistant steel, high temperature, numerical processing, mathematical pattern-making Amalia Ana DASCĂL, MAKSAY Ştefan, Camelia PINCA-BRETOTEAN, HEPUŢ Teodor: Numerical researches on the optimalization of the chemical composition for OLT 35K steel with a view to obtaining superior mechanical features at high temperature Metalurgia International (vol. XI), no.1, 2006, p. 28 The paper presents the results of the research made under laboratory experimental testing, on OLT 35K steel, intended to the manufacturing of tubes, used at high temperature in

the make-up of thermal-energetic installation. Mechanical driving testing has been made at the temperature of 450°C, on shares of test-bars drawn out of a number of 50 charges, with a view to achieving the optimalization of the chemical composition of this steel type. The optimalization, under experimental dates, suggests alternatives of combinations among the main elements of the chemical composition, so as the steel can be elaborated with superior mechanical features at high temperature. The obtained results have a large feasibility area, and can be also endorsed for other steel types and mechanical features for which the optimalization is viewed, therefore being very useful to technologists, in the process of achieving a certain type of steel. D.C.: 662.6; 66.047 Corneliu Stănăşilă, Constantin Nicolae, Stănăşilă Octavian, Toşcuţă Dragoş: New technology of coal’s drying Metalurgia International (vol. XI), no.1, 2006, p. 34 In this paper, one presents a new solution regarding the coal’s drying. The solution has been experimented in the case of drying ceramics and separately timber, the gaseous agent crossing the coal layer alternatively, by a system of flaps. One also presents some thermic and gasodynamic computations and a thermic balance, the drying efficiency reaching 93%. D.C.: 669.018.25 Catangiu Adrian, Ioniţă Gheorghe, Graţiela Petrişor: Characterisation of glass/epoxy composite laminates in uniaxial loading Metalurgia International (vol. XI), no.1, 2006, p. 39 This study describes the behavior of a cross-ply composite under uniaxial tension. The laminate configuration is (0/902/0). Specimens are cut out of the panels in the direction of θ = 0^0, 15^0, 25^0, 45^0 and 90^0. Tensile test were performed on the specimens. We observe that there is a very weak plastic deformation in the fiber direction and nonlinear stress-strain relations at others angles.