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Effect Of Defects On Fatigue Mechanical Properties Of Surface Quenched Axle

Posted on:2016-11-11Degree:MasterType:Thesis
Country:ChinaCandidate:H K LiFull Text:PDF
GTID:2272330485984179Subject:Materials Science and Engineering
Abstract/Summary:PDF Full Text Request
The axle of high-speed EMU is one of the core components of bogie and for wheel-rail interaction, and it is the components which will bear the most intense random dynamic load among the key components of high-speed EMU, crucial for safe operating of high-speed EMU. The surface quenched axles for high-speed EMU occasionally will have knock-on defects due to flying stones during passenger service, which will lead to latent safety hazards for safe operating of axles. However, there is not sufficient research on the influence of knock-on defects by stones to the property of surface quenched axles. Therefore, it is necessary to carry out systematic research on the influential rules of axle surface defects to the fatigue property of axles.This thesis has built the testing methods for evaluating the influence of such defects to the fatigue property of surface quenched axles, systematically researched the influence of knock-on defects by stones to the fatigue property of axle materials. It has defined the sampling method from quenched axles and fatigue testing method and developed corresponding fatigue testing jigs after analysis for the actual working conditions of axles. It built the model defects mode and defined the scope of values for included angle, depth, radius of bottom fillet suitable for the model defects after analysis for the real defects of axles.This thesis has researched on the influential rules of defect dimensions to the fatigue property of the axle specimens with surface quenched layer. The fatigue strength of high-frequency quenched axle specimens for CRH2 high-speed EMU is tested by means of Bruceton Method under different surface quality and different dimensions. After comprehensive data analysis and comparison between section profile changes of axle specimens with surface quenched layer under different defects, the influential rule of defects under different dimensions to the fatigue property of axle specimens with surfaced quenched layer has been found.
Keywords/Search Tags:Defect, Axle, Surface Quenching, Fatigue Property
PDF Full Text Request
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