Experimental Consideration of Conditions for Measuring Residual Stresses of Rails Using Magnetic Barkhausen Noise Method.

Young-In Hwang,Yong-Il Kim,Woo-Sang Lee,Dae-Cheol Seo,Ki-Bok Kim,Segon Kwon,Mu-Kyung Seo

doi:10.3390/ma14185374

Abstract

Residual stress, a factor affecting the fatigue and fracture characteristics of rails, is formed during the processes of fabrication and heat treatment, and is also generated by vertical loads on wheels due to the weight of vehicles. Moreover, damage to rails tends to accelerate due to the continuous increase in the number of passes and to the high speed of passing vehicles. Because this can have a direct effect on safety accidents, having a technique to evaluate and analyze the residual stresses in rails accurately is very important. In this study, stresses due to tensile loads applied to new rails and residual stresses remaining in used rails were measured by using magnetic Barkhausen noise method. First, a magnetization frequency and noise band suitable for the rails were selected. Moreover, by applying tensile loads to specimens and comparing the difference in magnetization amplitudes for each load, the stresses applied to the rails by using the magnetic Barkhausen noise method were measured, and the analysis of the results was verified. Based on these results, the difference in the results for the loads asymmetrically applied according to the wheel shape was analyzed by measuring for the head parts of used rails.

Highlights

Introduction iationsRecently, in the railway field, the conditions during use of important parts, such as rails, wheels, and axles, have become increasingly harsh because the high-speed rail networks operating worldwide have increased
Were found to be relatively higher than those from other specimens. It was verrails, using the magnetic properties of the material, and the following results were obtained ified that the difference according to the residual stresses can be expressed by using magthrough this study
It was found that the magnetic Barkhausen noise intensity values measured while applyrails, using the magnetic properties of the material, and the following results were obing tensile loads increased linearly with the increase in tensile load when the direction of tained through this study

Summary

Introduction

In the railway field, the conditions during use of important parts, such as rails, wheels, and axles, have become increasingly harsh because the high-speed rail networks operating worldwide have increased. The length of the highspeed networks in commercial operation worldwide has increased by 3.6 times [1]. The rails are repeatedly loaded with extreme weight according to how the vehicles are operated, so defects in the rails can develop very quickly and lead to damages to the rails. Under conditions in which rail defects cannot be detected early, the possibility of train-derailment accidents due to the rail damages increases. This means that reliability the evaluation of rails is essential to prevent such accidents.

Methods

Results

Conclusion