Papers by Keyword: Flash Butt Weld

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Authors: Magdalena Šmátralová, Jana Kosňovská, Gabriela Rožnovská, Václav Kurek
Abstract: The paper describes the rail failures occurring repeatedly in the same distance from the rail butt weldment. The results of this investigation, especially fractographic analysis of the fracture surface of rail, evaluation of its macrostructure and microstructure, EDS analysis and hardness measurements revealed that transverse crack initiated in the foot of rail gauge and propagated by fatigue mechanism until the final cleavage fracture.
Authors: Oliver Kirstein, Vladimir Luzin, Alain Brule, Hien Nguyen, David Tawfik
Abstract: The Australian Nuclear Science and Technology Organisation (ANSTO) has recently started commissioning the new Australian Research Reactor OPAL that has replaced the old HIFAR reactor in January 2007. At the first stage, the new reactor will provide neutrons to several neutron scattering instruments. Among them is the residual stress diffractometer Kowari that was designed to study engineering problems related to residual stresses as well as allow material science research using neutron diffraction. We give an update on the progress of the instrument’s installation and commissioning and present an example to illustrate how neutron diffraction can be used to obtain information about residual stresses in a flash butt welded plate.
Authors: Toshio Kuroda, Kenji Ikeuchi, Takeshi Terajima
Abstract: Super duplex stainless steels were welded using new flash butt welding technology of temperature controlling system. The super duplex stainless steel (329J4L) and conventional duplex stainless steel (329J3L) were used. The samples were mounted in the dies using a Gleeble thermal simulator and flash but welding was made. The specimens were heated up to 1373K for 10sec, 20sec and 30sec. Flash butt welding has consisting of a two stage processes of a flash action and a contact resistance. First stage was a flash welding process and second stage was a solid state bonding process. The cross sectional microstructure of the weld bond region showed two types of a deposited fine particles region and a solid state bonding region. The grain growth was hardly observed in the weld region and the heat-affected zone. For further increasing joining efficiency of solid state bonding at the second stage, the welding time at 1373K was increased from 5 sec to 180sec. The bonding area increased with increasing welding time at 1373K and successfully welded for conventional duplex stainless steel.
Authors: Shao Hua Yan, Hui Chen, Guo Qing Gou, Da Li, Yan Liu, Zhong Yin Zhu
Abstract: The residual stress,which is unavoidable in the process of flash-butt-weld rails,plays important roles in the service life of the railway rails.However,knowledge of magnitude,direction,and sign of the residual stress is useful for maintenance and failure prevention.In this paper,we measured the residual stresses in the flash-butt weld of the U71Mn railway rail,using X-ray diffraction method.Besides,we investigated the influence of grinding on residual surface stress.This investigation showed that residual stress generated by grinding could be removed by electro-polishing,we also found that there was longitudinal compressive stress in the foot and head region,while the web region presented tensile stress,and in the transverse position,all of the three regions existed both compressive and tensile stress.
Authors: Oliver Kirstein, Maurice I. Ripley, David Tawfik
Abstract: Neutron scattering using diffraction techniques is now recognised as the most precise and reliable method of mapping sub-surface residual stresses in materials and industrial devices. It was therefore decided to build the dedicated strain scanner KOWARI among the first suite of instruments for the new Australian Replacement Research Reactor OPAL. In order to support the new instrument and familiarize the Australian user community with the technique a „Neutrons for Engineering“ project has been established to provide a fully integrated residual stress service. To make use of the neutrons at Australias HIFAR reactor the existing three-axis spectrometer has been refurbished and modified to allow strain measurements. The Australian Strain Scanner (TASS) will operate until the new strain scanner becomes operational in 2006. Apart from giving an overview about the technique and properties of the new strain scanner we would like to present and discuss two case studies: a) residual-stresses obtained from a break-disc of a car and b) residual-stresses within a flash-butt welded plate cut out of a railway.
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