Research On Residual Stress And Microstructure And Properties Of EA4T Axle Steel

EA4T steel is a European brand of high-quality low-carbon alloy steel,which is mainly used in subway axles and high-speed EMU axles.Its service performance and service life are closely related to the safety of trains.The transition arc of the EA4 T axle is complex in the service process.The initial state such as the heterogeneity of the microstructure and residual stress distribution of the material in this part will affect the organization and stress state of the material during subsequent service.However,at present,in the domestic research on the localization of the car shaft,the domestic EA4 T steel has a point-like segregation,the quenching permeability of the axle steel is poor,and a massive copolymeric ferrite body has gradually increased along the heart,causing material cleavage cracking.,Reduce the toughness and plasticity of the material.In view of this,this study measured and observed the state of organization and residual stress at the rolling arc of the imported EA4 T axle,and constructed the constitutive relation of the rolling process of the axle,providing a reference for the rolling simulation of the axle.The study provides a valuable reference for the influence of the initial state of the EA4 T axle on the organization and stress state of the material during service.The study provides a reference for the localization study of the axle.The microstructure and hardness of different parts of axle transition arc were studied by means of X-ray diffraction(XRD),scanning electron microscope(SEM),short-wave long X-ray body stress nondestructive analysis,microhardness analysis and finite element analysis(CAE).Characterized with performance,The residual stress distribution of different parts of the axle from the inside to the surface along the radial direction was measured and analyzed by the short-wave X-ray stress analyzer.Studies have shown that the grains at the transition arc of the EA4 T axle are small and uniform,and the axles are made of martensite and bainite.After rolling,the crystals cause extrusion and plastic deformation of the crystals,and the grains become significantly smaller and elongated.A large number of M-A islands were precipitated during the cooling process,and M-A islands were precipitated along the crystals in a small dispersion.Due to rolling,the axle surface has a distinct texture.The densely packed(110)plane is parallel to the rolling surface,The texture of the interior of the axle is(211)?axial and(100)?axial,which is consistent with the(211)?axial and(100)?axial,axial contours Rolling treatment obviously improves the hardness of the axle,forming a layer of hardening layer on the surface of the axle,which can increase the strength of the axle while increasing the hardness.The stress distribution of the roller layer was studied by means of tungsten target,Chromium target,simulation calculation,etc.The residual stress distribution of the roller layer at the transition arc of the EA4 T axle was affected by the rolling.The axial pressure stress value at the bottom of the layer surface of 7?m was-492 MPa,The circumferential pressure stress value is-382 MPa,the average axial residual stress value of 300 ?m is-411 MPa,and the average value of circumference residual stress is-272 MPa.The finite element calculation of the axial residual stress is-287 MPa,and circumference residual stress is-203 MPa.The internal stress distribution was studied,uniform and uniformly compressive stress,the stress value of 4 # points was the largest,circumference residual stress reached-240.6 MPa,and the axial residual stress reached-84.5 MPa.