Revista SUDURA

Nr. 3/2014

 

 

 

❯ Deflection and pre-cambering of the welded steel beams**)

Prof. dr. ing. Radu Băncilă1), S. l. dr. ing. Dorel Bolduş1), Dr. ing. Anamaria Feier2), As. dr. ing. Silvia Hernea1), Ing. Mihaela Maliţa1), 1) Universitatea POLITEHNICA Timişoara, 2) Asociația de Sudură din România, INCD Urban Incerc Timișoara

Abstract: The paper presents the calculus of the pre-cambering deflection and makes some recommendations in this direction.Steel beams are used in the construction of high-rise buildings, bridges, commercial and industrial buildings andmany other structures. A camber means to design the beam in such a way as to reduce the deflection under load.Pre camber is necessary in beams - especially with large spans, like bridges, in order to ensure a good operation ofthe structure and to reduce the visual deflection which is one of the requirements of deflection checking.Keywords: steel beams, deformation, pre cambering.

❯ New approaches in the field of Friction Stir Welding. New surfacing and soldering techniques developed on the basis of FSW principle**)

Ing. Radu Cojocaru, Ing. Lia Boţilă, Ing. Cristian Ciucă, Dr. ing. Victor Verbiţchi, Ing. Aurel Perianu, Ing. Horia Daşcău, Institutul Național de Cercetare-Dezvoltare in Sudură șiIncercări de Materiale (ISIM) Timișoara, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract: The paper presents new approaches opportunities in the field of material joining using the friction stir weldingprocess (FSW) based on the results of research carried out at ISIM Timisoara.The difficulties that appear at FSW of some material categories have determined promotion of the innovativehybrid FSW-TIG process.FSW process principle was the basis of developing new techniques usable at surfacing materials and also developingnew soldering techniques.In this paper two new methods proposed by the authors are presented for monitoring the FSW process: infraredthermography and controlling the motor energy consumption which ensures the tool rotation.Keywords: FSW, FSW-WIG, functional layers, bonding, monitoring.

 Experimental researches regarding the qualitative optimization of the laser cutting process of metal sheets made of S355JR steel **)

Dr. ing. Cristian Petrianu 1), Prof. dr. ing. Marius Bibu 2), Conf. dr. ing. Cristian Deac 2), Prof. dr. ing. Valentin Petrescu 2), 1) Claudius Peters GmbH, Buxtehude, Germania, 2) Universitatea „Lucian Blaga” din Sibiu, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract:The usage of the laser cutting process for metallic materials has spread steadily in recent years, being applied ina multitude of area. Nevertheless, many aspects related to the obtaining of an optimal quality of the laser cutsurfaces are still insufficiently studied. The authors of the current paper have therefore intended to study theoptimisation possibilities, from the point of view of surface quality, of the laser cutting process for a part madeof S355JR steel. Based on the data obtained experimentally and processed using the Design Expert softwarepackage, a mathematical model was obtained that allows a description of the variation of the surface roughness,as a parameter of the surface quality, function of the parameters of the technological system for laser cutting:cutting speed, cutting gas pressure, laser power, laser efficiency and frequency.Keywords: laser cutting, optimization, surface quality, mathematical model, cutting parameters

 Cu-Cr and Cu-Cr-W composites dedicated to spot resistance welding

Ing. Maria Miclău, Prof. dr. ing. Mihail Mangra, Conf. dr. ing. Ionel Dănuţ Savu, Universitatea din Craiova

e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract: This paper presents the results of experimental research into developing sintered composites with copper matrix, and reinforcement of chromium and tungsten particles, for the manufacturing of electrodes for spot resistancewelding. Materials used in the experiments were groups of Cu-(1.0%, 1.5%, 2.0%, 4.0%) Cr and Cu-(1.5%,2.0%) Cr-5% W. As in the experiments presented in an earlier article, the materials thus obtained were used forthe construction of active elements mounted on commercial electrodes, as active elements. The new electrodeswere subjected to specific tests of welding in order to evaluate their behavior. The used regimes of welding (weldingcurrent [kA] were: 4.8, 6.0, 7.2, 8.4). During the tests the weight loss of each electrode was measured andaspects of the surface were analyzed. Results showed excellent behavior of the composite Cu-Cr compared toCu-Cr-W. The introduction of 4% chromium had superior effect on the behavior of the material, comparing toall other recipes, at any adjusted welding currents. This relatively high chromium addition contributed to the increasingof the mechanical strength and to a decreasing of pullout phenomena of the sintered material. Althoughelectrical conductivity was higher in the case of content of 1% or 1.5% Cr, however, increasing the chromium to4% Cr involved not only appropriate electrical conductivity but mechanical strength during the pressing forceapplication. Additions of tungsten have created conditions for pulling-out sintered material from the surface ofthe active element. Best behavior as active element had the composite Cu-4% Cr.Keywords: sintered spot resistance welding electrodes, Cu-Cr and Cu-Cr-W powders content, mass loss

 Evolutions of standardization in the field of welding personnel qualification**)

Ing. Petru Ţenchea, Președinte ASRO/CT 39 – Sudare și procedee conexe, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract: The most recent standards in the field of welding personnel qualification, prepared by the International Organizationfor Standardization (ISO/TC 44 – Welding and allied processes) and the European Committee forStandardization (CEN/TC 121 - Welding and allied processes) are presented, together with the future concernsof these bodies. EN ISO 9606-1:2013, related to the qualification testing of welders for steel fusion welding,replaces EN 287-1: 2011, an harmonized standard to the Directive 97/23/EC (PED), referenced in all thea pplication European standards for welded products. The main aspects of the new standard are presented. Theimplementation of this standard will affect significantly the European actual practices. The steps to adopt thisstandard in the national standardization of the CEN countries are also presented. The second standard presentedin this work, SR EN ISO 14732:2013, related to the qualification testing of welding operators and weldsetters for mechanized and automatic welding of metallic materials, replaces SR EN 1418-2000. The futureconcerns include the systematic review of existing standards and the revision of two standards related to thequalification of personnel for underwater welding. Keywords: welder, qualification, international standard, European standard 

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