Method for researching friction corrosion behavior of steel rail foot

Abstract

The invention discloses a steel rail foot friction corrosion behavior research method, and belongs to the technical field of railway steel rail service performance research and failure mechanism evaluation. The research method comprises the following steps: preparing a U75V steel rail and PA66 lining cylindrical sample, constructing a test platform consisting of a control motor and an electrochemical test system, carrying out reciprocating friction and potentiodynamic and constant potential corrosion loading in a 3.5% NaCl solution, collecting corresponding corrosion current data, and analyzing the surface failure behavior. The invention aims to provide the method for researching the friction corrosion behavior of the rail foot of the steel rail, which is characterized in that a repeatable, controllable and low-cost test platform is constructed by simplifying an experimental device and combining a control motor and an electrochemical system, and a cooperative acceleration failure mechanism between fretting wear and crevice corrosion is disclosed.

Description

Technical Field

[0001] This invention belongs to the technical field of railway rail service performance research and failure mechanism assessment, and particularly relates to a method for studying the frictional corrosion behavior of rail feet. Background Technology

[0002] As a crucial component of the rail structure directly bearing gauge force and track bed load, the rail foot faces complex physical and chemical environments during long-term service. This is especially true in the micro-crack areas formed under the pressure of gauge blocks (such as PA66 linings), which are prone to mechanically assisted crevice corrosion (MACC) under dynamic train loads. MACC is a form of accelerated material degradation caused by the coupling effect of fretting and crevice corrosion, manifested as crack initiation, localized corrosion collapse, and failure propagation. Potentiodynamic polarization (VNP) testing, by applying a potential scan, can obtain the polarization curve of the material in a short time, rapidly determining key parameters such as corrosion current density and corrosion potential to assess the material's corrosion resistance. It is a commonly used electrochemical research method for evaluating metal corrosion behavior. Potentiostatic polarization can precisely control the potential of the working electrode, maintaining it at a set value, thereby enabling selective research on specific electrochemical reactions. It can also reveal the kinetic parameters of the electrode process (such as corrosion current density and Tafel slope) through dynamic or static polarization curves, providing quantitative evidence for assessing material corrosion resistance or electrocatalytic activity. Existing research mainly focuses on the individual effects of friction or corrosion, lacking experimental simulation methods for the interaction and coupling mechanism between the two, and especially lacking simplified experimental models and quantitative evaluation systems applicable to the actual contact relationship between rail foot and lining. Summary of the Invention

[0003] The purpose of this invention is to provide a method for studying the frictional corrosion behavior of rail feet. By simplifying the experimental setup, a repeatable, controllable, and low-cost testing platform is constructed using a combination of control motors and electrochemical systems to reveal the synergistic accelerated failure mechanism between fretting wear and crevice corrosion.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] This invention discloses a method for studying the frictional corrosion behavior of rail feet, comprising: preparing U75V rail and PA66 inner lining cylindrical samples, constructing an experimental platform consisting of a control motor and an electrochemical testing system, performing reciprocating friction and potentiodynamic and constant potential corrosion loading in a 3.5% NaCl solution, collecting corresponding corrosion current data, and analyzing surface failure behavior.

[0006] Furthermore, the displacement amplitude of the motor is 10–200 μm, and the frequency range is 1–5 Hz.

[0007] Furthermore, the electrochemical system uses a saturated calomel electrode as the reference electrode and a platinum sheet as the counter electrode.

[0008] Furthermore, by utilizing potentiodynamic polarization, the self-corrosion potential and self-corrosion current density can be obtained.

[0009] Furthermore, corrosion current data were obtained by utilizing constant potential polarization.

[0010] Further corrosion analysis was performed using scanning electron microscopy to observe cracks, collapses, and pearlite corrosion morphology.

[0011] Furthermore, the duration of the friction corrosion loading was between 10 and 60 minutes.

[0012] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0013] This invention constructs an experimental platform consisting of a control motor and an electrochemical testing system. The platform has a simple structure, controllable test parameters, and high simulation accuracy. It is suitable for studying the corrosion behavior of rail foot gaps and can reveal the synergistic failure mechanisms of friction-induced stress, corrosion fatigue, and material detachment, providing a theoretical basis for rail material selection and service safety assessment. Attached Figure Description

[0014] Figure 1 Tafel curves at 1Hz and 5Hz frequencies for the same amplitude of 10µm.

[0015] Figure 2 Tafel curves at the same frequency of 1Hz, with amplitudes of 10µm and 100µm. Detailed Implementation

[0016] A method for investigating the frictional corrosion behavior of rail feet is characterized by the following steps: preparing cylindrical samples of U75V rail and PA66 lining; constructing an experimental platform consisting of a control motor and an electrochemical testing system; subjecting the samples to reciprocating friction and potentiodynamic and constant potential corrosion loading in a 3.5% NaCl solution; collecting corresponding corrosion current data; and analyzing the surface failure behavior.

[0017] The motor displacement amplitude ranges from 10 to 200 μm, and the frequency range is from 1 to 5 Hz. The electrochemical system uses a saturated calomel electrode as the reference electrode and a platinum sheet as the counter electrode. Self-corrosion potential and self-corrosion current density are obtained using potentiodynamic polarization. Corrosion current data are obtained using potentiostatic polarization. Corrosion analysis is performed using scanning electron microscopy to observe the morphology of cracks, collapses, and pearlite corrosion. The duration of tribocorrosion loading is between 10 and 60 minutes.

[0018] Case Study:

[0019] A method for investigating the frictional corrosion behavior of rail feet includes the following steps:

[0020] 1. Sample preparation: Cut U75V rail foot samples and PA66 inner lining samples, and grind, inlay, and polish them.

[0021] 2. Test setup: The reciprocating motion is provided by a controllable motor, and the corrosion electrical signal is collected by an electrochemical system.

[0022] 3. Friction corrosion loading: Control the frequency / displacement to simulate service conditions and record the corresponding current changes.

[0023] 4. Surface analysis: SEM was used to observe the surface morphology of the U75V sample.

[0024] 5. Mechanism Analysis: Combining corrosion current and morphology information, the damage mechanism of MACC is analyzed.

[0025] Electrochemical experiments were conducted on U75V steel rails with the same motor amplitude but different frequencies in 3.5% NaCl solution, and the corresponding potentiodynamic polarization curves were obtained. Figure 1 Electrochemical experiments were conducted on U75V steel rails in 3.5% NaCl solution at the same motor frequency but different amplitudes, and the corresponding potentiodynamic polarization curves were obtained. Figure 2 .

[0026] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for studying the frictional corrosion behavior of rail feet, characterized in that, include: Cylindrical specimens of U75V steel rails and PA66 inner linings were prepared. An experimental platform consisting of a control motor and an electrochemical testing system was constructed. Reciprocating friction and potentiodynamic and constant potential corrosion loading were carried out in 3.5% NaCl solution, and corresponding corrosion current data were collected to analyze the surface failure behavior.

2. The method for studying the frictional corrosion behavior of rail feet according to claim 1, characterized in that, The displacement amplitude of the motor is 10–200 μm, and the frequency range is 1–5 Hz.

3. The method for studying the frictional corrosion behavior of rail feet according to claim 1, characterized in that, The electrochemical system uses a saturated calomel electrode as the reference electrode and a platinum sheet as the counter electrode.

4. The method for studying the frictional corrosion behavior of rail feet according to claim 1, characterized in that, By utilizing potentiodynamic polarization, the self-corrosion potential and self-corrosion current density can be obtained.

5. The method for studying the frictional corrosion behavior of rail feet according to claim 1, characterized in that, Corrosion current data were obtained by using constant potential polarization.

6. The method for studying the frictional corrosion behavior of rail feet according to claim 1, characterized in that, Corrosion analysis was performed using scanning electron microscopy to observe cracks, collapses, and pearlite corrosion morphology.

7. The method for studying the frictional corrosion behavior of rail feet according to claim 1, characterized in that, The duration of the friction corrosion loading was between 10 and 60 minutes.

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