H. B. Pereira, E. Echeverri, L.H.D. Alves, H. Goldenstein
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引用次数: 4
Abstract
Abstract Simulations using the finite element method (FEM) were done to understand the effects of heating/cooling rates on the distribution of residual stresses. Two material parameters from rails were used while the boundary conditions remained constant: heat-affected zone size, maximum temperature and heating extraction rate. To complement the analysis, a flash-butt weld of a Premium rail was done with welding parameters adjusted to obtain a narrow HAZ, without forced cooling, to examine the microstructure formed in the critical regions in the web and the edge of the rail foot. The results showed that there was a concentration of vertical residual stresses in the web region, while the presence of horizontal compression residual stresses was mostly superficial in the rail head region. The main result from the simulation sets was that when using two simulation parameters with similar materials (rails) substantially different results were obtained. Metallographic examinations showed that there was no presence of acicular microconstituents (martensite/bainite). In the rail web, proeutectoid ferrite was observed in the central region, cementite in a previous austenitic grain boundary, in the region that reached temperatures close to AC3, and almost complete spheroidization in the region of maximum spheroidization. In contrast, in the rail foot edge region, there was a completely pearlitic microstructure, in the central region and in the zone that reached temperatures close to AC3, and a lower volume of spheroidization in the region where maximum spheroidization is typically observed, probably due to the higher cooling rate in this region.
期刊介绍:
The Journal Soldagem & Inspeção (S&I) js a techno-scientific journal created in 1995. Printed issues of this journal are distributed free of charge to libraries in Brazil, Latin America and the Iberian Peninsula. It has been printed regularly every quarter since September, 2002, and, since the beginning of 2007, its electronic version is available in the address: (http://www.abs-soldagem.org.br/s&i/). The journal is sponsored by the Brazilian Welding Association (ABS).
Since its creation several well known professionals working in welding contributed with the Journal Soldagem & Inspeção and its editorial board crosses the Brazilian borders. During its evolution the Journal received ta special contribution from the Editors-in-chief : Ronaldo Paranhos, Américo Scoti, Paulo Modenesi e Alexandre Bracarence. Since January 2012 the Editor-in-chief is Ana Sofia C. M. D’Oliveira, Full professor at Universidade Federal do Paraná (UFPR) . Her work focus mainly on Hardfacing and Physical Metallurgy. The jornal Soldagem & Inspeção also counts with 10 Associate Editors and a fix Editorial board of referees. short-term (Ad Hoc) referees can be invited to evaluate some papers submitted to the journal.
The Soldagem & Inspeção journal is the scientific divulgation channel of the Brazilian Welding Association (ABS). It aims to publish original papers related to the scientific and technological development of welding, inspection, and related fields. Review papers or letters on current and controversial subjects are also published in the Journal.
Its abbreviated title is Soldag. insp. (Impr.), which should be used in bibliographies, footnotes and bibliographical references and strips.