Failure Analysis of Train Vehicles Engagement Arm
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This paper studies the failure reasons of train vehicles engagement arm. The arm ends with screw. From the statistical observation, it is found that the failure always happens in the screw region. The steel used in this engagement arm is carbon steel of 0.40C–0.26Si–0.68Mn–0.068Cr chemical composition in wt.%. The non-metallic inclusions were followed and studied in the screw profile (root, flank, and matrix) using optical and SEM microscope. The tensile testing was carried out to compare with the standard values. Optical microstructure reveals ferrite-pearlite bands. EDS-SEM revealed that the segregation of Mg in the non-metallic inclusions creates micro-shrinkage porosity around the non-metallic working as stress concentrators during the service leading to catastrophic cracks.
KeywordsPush–pull fatigue Non-metallic inclusions Screw of bolt Engagement arm SEM microstructure Tensile Strength Shrinkage porosity due to high Mg
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