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Copyright © 2007 editura Științifică F.M.R.-Bucharest, Romania

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 Metalurgia

INTERNATIONAL

(magazine set-up in 1995)

 

English version, published by

romanian metallurgical foundation

 

Honorary president of  scientific publishing house f.m.r.

Dr. ec. Lepădatu v. gheorghe

 
                       

                                                        vol. XII

                                                                  (2007)

                                                                  no.7

 

romanian metallurgical foundation

Scientific publishing house

Honourary Staff

(in alphabetical order)

 

bensabra    hakim    (algeria),    BORDEA MARIUS, chabour    salem    (algeria),     gencang    yang    (china), 

  R.  S.     HOUK     (S.U.A.), I. IMRIŠ  (TECHNICAL  UNIVERSITY  OF  KOŠICE,  SLOVAK  REPUBLIC),      pușici miho (Slovenia), roșescu     gheorghe  (grecia),     roxana  ruxandra     (california),   w.m. nicola (tri. state university angola, indiana, s.u.a.), xianqing you (china)

 

 

romanian metallurgical foundation

Scientific publishing house

 

editorial  board :

 

Prof. colan horia Ph. D., member of Romanian Academy of Technical    Sciences

Prof. Coșmeleață georgeta Ph. D.

Prof. Elena drăgulănescu Ph. D., Catedra GDGI,  Aerospatial Engineering Faculty, Bucharest Politechnical University

Prof. Dumitrescu Constantin Ph. D., deputy member of Romanian Academy of Technical Science

Prof. French David Ph. D., CSIRO Energy Technology, Australia

Prof. Gălușcă Dan-Gelu Ph. D.

Prof. Mihaela Grigore Ph. D., University of New South Wales, Sydney, Australia

Prof. Lawson Cristopher Ph. D., Copenhague Technical Institute, Denmark

Prof. Nicolae Avram Ph. D.

Prof. Maria Nicolae Ph. D.

Prof. doc. Oprea Florea Ph. D., member of Romanian Academy of Technical Sciences

Prof. Veena Sahajwalla Ph. D., University of New South Wales, Sydney, Australia

Prof. Sakurovs Richard Ph. D., CSIRO Energy Technology, Australia

Prof. Salvo Luc Ph. D., Grenoble National Politechnical Institute, France

Prof. Saiter Jean-Marc Ph. D., Rouen University, France

Prof. Scorțea Costin Ph. D.

Prof. Simiti Ioan Vida Ph. D.

Prof. Sofroni Laurenție Ph. D., member of Romanian Academy of Technical Sciences

Prof.  Șaban Rami Ph. D., Dean of  Materials Science Faculty, Bucharest Politechnical University

Prof. ȘTEFĂNESCU DORU Ph. D, Ohio State University   Columbus, S.U.A.

 

advisory board :

 

Prof.  bejan Mircea Ph. D

Prof.  cănănău nicolae  Ph. D

Prof.  hepuț teodor Ph. D

Prof.  Miloșan Ioan Ph. D.

Prof.  Doina Răducanu Ph. D

Prof.  samoilă Corneliu  Ph. D

Prof.  SOFONEA GALAgTION Ph. D

Prof.  VARGA BELA Ph. D

 

Managing Director:

Editor-in-chief:

Professor Scorțea Costin Ph. D.

 

Manager Scientific Publishing House F.M.R.:

eng. Florentina Brândușa Scorțea

Contents

 

Issn 1582 – 2214

 

Maria NICOLAE, Irina VÎLCIU, Avram NICOLAE, Radu VÂRLAN: Improving the lubrication process

 during cold rolling by using the cavitation

phenomenon in liquids ……………………..… 5

 

Avram NICOLAE, Maria NICOLAE, Netty – Brândușa MILEA, Radu VÂRLAN: Contribution

of double reversible cold drawing to the

increase of plates quality for enamelling …... 10

 

Ciobanu Ioan, Mașniță Mihai, Monescu Vlad, Roșescu gheorghe: Research concerning

castings solidification with section “T” ……. 18

 

VASIU Teodor, Diana STOICA:   Methods  to

determine the preventive maintenance

cycles of rolling mills ………………………... 27

 

Munteanu I. Sorin, Ciobanu Ioan, Crisan Aurel, Masnita Mihai, Avram Nengis, STROE Florin: Experimental and computer simulation

Researches  about the hot spots position

during  the  solidification  of  bars  with

„U” section ………………………………...… 35

 

LEVCOVICI LEVCOVICI  Dan T., Sanda LEVCOVICI, Simona BOICIUC:   Studies   and   researches

regarding laser cladding of nickel alloys

 on a steel support ………………………….... 41

 

MILOSAN Ioan: Study about the mechanical

properties of a cryogenic S.G. cast iron ……. 47

 

 

? FOSECO Turbostop system – reference list… I-II

? Press Release..............…..……………..…...... III-V

? New books, published by romanian metallurgical

foundation……………….………........…..... VI-VII

abstract

metalurgia International 7/2007

 

 

D.C.: 621.745.44

Maria NICOLAE, Irina VÎLCIU, Avram NICOLAE, Radu VÂRLAN: Improving the lubrication process during cold rolling by using the cavitation phenomenon in liquids

Metalurgia International (vol. XII), no.7, 2007, p. 5

One of the important parameters which have influence on cold rolling is the stability of emulsions used for lubrication. When launching the research theme, one considered that the stability of water-oil emulsions can be improved using the effect of cavitation in liquids. One performed researches on an original installation using the cavitation effect for activation. The investigations results presented concern: the stability of emulsion processed by cavitation, its application effect on the relative reduction at a pass and on the number of passes required by the  technology.

 

 

D.C.: 574

Avram NICOLAE, Maria NICOLAE, Netty – Brândușa MILEA, Radu VÂRLAN: Contribution of double reversible cold drawing to the increase of plates quality for enamelling

Metalurgia International (vol. XII), no.7, 2007, p. 10

There are researches aiming to substitute the simple cold drawing by the reversible double cold drawing in order to manufacture plates for enamelling. The experiments (running on small and on large scale) had in view to state the quality of adherence to enamelling for both manufacturing versions (simple cold drawing and double cold drawing). One presents, also, the results concerning the connection between cold drawing and enamelling using the metallographic structures and mechanical properties.

 

 

D.C.: 621.746.628

Ciobanu Ioan, Mașniță Mihai, Monescu Vlad, Roșescu gheorghe: Research concerning castings solidification with section “T”

Metalurgia International (vol. XII), no.7, 2007, p. 18

It was made a research by computer simulation of the solidification regarding castings solidification with section ”T”. It was analysed the influence of the rib thickness and length at the ”T”-shaped walls intersection over the solidification time, over the shape coefficient and over the thermal nodes position.

 

Key words: the preventive maintenance cycles of rolling mills

VASIU Teodor, Diana STOICA: Methods to determine the preventive maintenance cycles of rolling mills

Metalurgia International (vol. XII), no.7, 2007, p. 27

This   survey   presents   two mathematical  models  of

preventive maintenance that take into account stochastic factors which influence the failure rates and working life of an entity. The models are hybrid so that they combine the reduction of proper operation time with failure rate. The starty point consists in idea that preventive maintenance is done with imperfections: it is not reduced the proper operation only but it is increased the probability of entity failure as much as the number of maintenance is increased. The target of this survey is to determine the optimal graphic of planned maintenance activities either to reduce the related costs or to maintain the reliability above a prescribed  minimum level.

 

Key words:  casting, simulation, solidification.

Munteanu I. Sorin, Ciobanu Ioan, Crisan Aurel, Masnita Mihai, Avram Nengis, STROE Florin: Experimental and computer simulation researches about the hot spots position during the solidification of bars with „U” section

Metalurgia International (vol. XII), no.7, 2007, p. 35

There are shown the results of an experimental research on the solidification of bars with „U” section.   It was analyzed the influence of inner opening of the „U” profile on the hot spot position. The experimental results are compared with the results obtained simulating the solidification on computer.

 

 

Key words : laser cladding, nickel alloy, microstructure

LEVCOVICI T., Sanda LEVCOVICI, Simona BOICIUC: Studies and researches regarding laser cladding of nickel alloys on a steel support

Metalurgia International (vol. XII), no.7, 2007, p. 41

In order to increase the wear and corrosion resistance of 0.45% C surface steel layers, a multilayer coating was tested by injection, in the melted bath produced using a CO2 continuous wave laser, of a powder with 8.9% Cr, 4.5% Fe, 5.1% B, 2.4% Al, 0.6% Cu, all remainder of Ni. To determine the optimum melting regime, the layers obtained by different laser conditions were characterized by HV5 hardness, macro and microstructure analysis.

 

 

Key words: Materials Science, S.G. Cast Irons, A.D.I., low temperature, mechanical properties

MILOSAN Ioan: Study about the mechanical properties of a cryogenic S.G. cast iron

Metalurgia International (vol. XII), no.7, 2007, p. 47

The paper presents the influence of the temperature and the maintained time at the isothermal level over the structure and properties of a nodular cast iron maintained at some low temperatures.

 

Attention !

 

E According to paragraph 2.6 of license agreement between EBSCO Publishing Inc. (U.S.A.) and FUNDAȚIA METALURGIA ROMÂNĂ   (ROMÂNIA) the  journals METALURGIA and METALURGIA INTERNAȚIONAL are  included in EP  Products, starting  from July 1st, 2006.

E These journals are included on EBSCO’s site: www.ebscohost.com , chapter „Computers and Applied Sciences Complete”, pozitions 1026 and  1027.

E Starting from January 1st  the  journal METALURGIA INTERNATIONAL is also in the SCOPUS database, belonging to ELSEVIER BIBLIOGRAPHIC DATABASES – Amsterdam (Netherlands).

 

1.      The “METALURGIA INTERNATIONAL” magazine receives manuscripts of papers including basic  scientific research and industrial  research in the following fields: metallurgy, materials science and engineering and different relating processes.

2.      Original papers not previously publishing  in any other journal, or not sent for publishing before, are accepted.

3.      After publication, the copyright is transferred to the publishing house.

4.      Every manuscript will be referred, their reports form the basis of the Editor’s decision.

5.      The manuscripts sent to the Editor  will not returned to the author, even  they are not published.

6.      The manuscripts will be sent to the following address:

METALURGIA INTERNATIONAL

83, Calea Griviței, sector 1, Postal code 010705, postal office 12

Bucharest, Romania

Tel.:  +(40)-1-310 71 38; +(40)-1-0722 665 071;

 Fax: +(40)-1-310 71 38

E-mail: redactia@metalurgia.ro; See also web: www.metalurgia.ro

REDACTION

 

Copyright © 2007 The f.m.r. scientific publishing house, accredited by the romanian council for universitary research