Welding of S355J+N Low Alloy Steel Elements in Railway Carriages Structures (original) (raw)
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Thermodynamic conditions during welding of railway carriage elements made of S355J+N STEEL
2021
The article aims to analyse the mechanical properties of carriage structures made of MAG-welded, lowalloy S 355J+N steel. Carriages are often made from thick-walled structures, which may cause problems during welding. The aforementioned issues stem from the chemical composition of the steel and electrode, the internal stress, as well as the thermodynamic conditions (which consist of the pre-heating temperature and interpass temperature). This article presents the properties of S 355J+N steel structures after MAG welding. In addition, non-destructive testing has been performed, and the metallographic structure and tensile strength of welded joints have been analysed. Different mixtures of argon with carbon dioxide or oxygen were used as the shielding gas, and the bevelling method used for sheets before welding was established. Welding speed was changed without pre-heating. The interpass temperature was controlled, so that it did not exceed 250°C. Warunki termodynamiczne podczas spawa...
2015
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The austenitic 316L steel (1.4401) is an important stainless material used to build various means of transport. Austenitic steel has high resistance to atmospheric corrosion. The austenitic steel is treated as a good weldable material, although cracks are possible. This paper analyses the influence of various MIG welding parameters on the creation of correct joints used in the stainless steel structures of mobile platforms elements, as an example of welding structures, in various means of transport. Various tests verifying the mechanical properties of MIG welds, including non-destructive tests, tensile strength and hardness tests, were carried out. This article aims to show how important and complex the task is to select the correct welding parameters for elements of means of transport made of austenitic steel on the example of elements of mobile platforms.
Material Optimization of Rail Track Welding and Validation using Finite Element Simulation
Railways provide a long and continuous journey for passengers and goods at an affordable cost. The rails and rail joints should be of high quality to ensure a safer transportation of people and goods. The tracks (rail) are made of alloys of iron and are fastened to other rails using fasteners. Nowadays, these fasteners are replaced with welded joints because of rising maintenance issues. Thermite welding is a globally adopted process for welding the rails. This article aims to best utilise the Aluminium composites for the welding of rails. The composites were prepared using stir casting route and a wear test was done on the casted samples to test their durability. Also, some of the mechanical properties of the composite material were found. The rail and track models were made and imported into ANSYS Finite Element Analysis software. The predicted results show that aluminium composites have considerable strength when compared to any other composite material.
Investigation of the Effects of Thermit Welding on the Mechanical Properties of the Rails
Acta Polytechnica Hungarica, 2022
This current paper deals with the investigation of the variation of the hardness of the rail steel material in the heat-affected zone (HAZ) of a rail joint made by thermit welding (TW). The tested rail is a normal R260 type rail steel category; its production date is 1977, the rolling mill was Diosgyor (Hungary), rail profile is MÁV 48.5. This rail has not been in railway track before the test. The authors performed hardness tests on the rail head's surface even after the rail welding, as well. After the welding and hardness tests, the rail joint was cut with +/-200 mm by a rail cutter and transported to the laboratory. Water jet cutting was applied to shape six longitudinal direction slices with five vertical cutting lines from the rail piece's head. The slices' length was 400 mm, the width of these slices was approx. 10 mm; the TW rail joint was in the mid-point of the slices. Micro-Vickers (HV10) hardness tests were executed on these slices, in the-150…+150 mm interval lengthwise and in the 3, 6, and 10 mm depth points below the rail head's top surface. As a result, the authors received a very detailed hardness functions of the HAZ of rail joint made by TW. These variation functions were compared to the official Elektrothermit's SoW-5 hardness tests' results. It can be concluded that the variation of the hardness of rail steel in the area of the HAZ correlated with the Elektrothermit's results; however, there were some critical points where significant differences were able to be found. The highest deviation was concluded in 50 mm distance measured from the axis of welded rail joint. The authors gave possible valuable explanations for these phenomena.
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Biuletyn Instytutu Spawalnictwa, 2020
Steels of the DOCOL group, characterised by high tensile strength and yield point, play an important role in the manufacturing of means of transport. However, the above-named steels are difficult to weld and joints made in them do not guarantee comparable mechanical properties. The research work discussed in the article aimed to determine process parameters suitable for the welding of a moving platform made of steel DOCOL 1200M as well as to assess the effect of welding parameters on the quality of obtained joints. The tests also involved analysing the effect of shielding gases, preheating and interpass temperature on the quality of an 8 mm thick MAG welded moving platform structure.
Quality and Fatigue Assessment of Welded Railway Bridge Components by Testing
Engineering Principles - Welding and Residual Stresses
During a decades-long program from 1953 to 1990, the quality of welded joints in railway bridges in Poland was assessed and quantified. It was discovered that many welded joints have technological cracks, and their quality is poor, especially in old constructions. Nearly, 200 bridges were tested using X-ray examination. The number of joints tested was over 15,000; cracks were discovered in 400 welded joints in the 34 bridges tested. To solve the problem, repeated examinations on welded joints with imperfections were undertaken and laboratory fatigue tests were performed. The tests and numerical analysis allowed fatigue behavior and tensile stresses in welded butt splices with cover plates to be recognized and excluded such a structural solution in bridges. The existing discontinuities and imperfections in welded joints following many years in service show no growths or forming of new cracks, as the applied stresses are below the threshold fatigue strength. As a result of decades of ...
2019
Friction welding, a solid state process, is a method that uses heat produced from friction. The produced heat in combination with an external pressure joins the two pieces of material in a weld. Friction welding has several benefits such as lower heat input compared to conventional welding, resulting in a narrower heat affected zone (HAZ), low environmental impact and no melting-solidification phenomena resulting in a structure free of impurities which gives better fatigue properties. These benefits are of particular interest to an ongoing EU-project ”Innovative Weld Processes for New Rail infrastructures” (WRIST). The present study considers the linear friction welding method (LFW), a method based on relative linear motion of two pieces under compression. A thermal finite element analysis is performed for the LFW process for two different steels, R260 and B360. For the simulations different heat generation models, pressures and welding times are used in different combinations. The ...