Electric Arc Surfacing of Defective Plots of Rails in the Area of Electrocontact Welded Joint

Dmitry Nezhivlyak,Andrey Nezhivlyak,M V Grechneva

doi:10.1051/matecconf/201929701004

Abstract

One of the main causes for the failure of the rails of a continuous joint made by electric contact welding is defects in collapse and wear in the joint zone. We address the usage of electric arc surfacing to repair defective rails. The structure and hardness are studied of the defective areas of rails recovered by electric arc surfacing performed in one and two layers. Static tests and fatigue tests of pilot samples of rails with eliminated defects were carried out. The pilot samples with defects eliminated by electric arc surfacing meet the criteria of static strength to the same degree as the rail samples without surfacing. The surfacing technology that we examined should be adjusted by applying preheating to reduce the cooling rate of metal in the weld zone. Fatigue tests showed a positive effect from surfacing at the wear sites in the welded joint. Performance tests confirm that electric arc surfacing is promising to eliminate defects in the collapse and wear of the rails in the area of the electric contact welded joint.

Highlights

The railways of Russia have over 92 thousand km of a continuous track, which has about 10 million welded rail joints
The study of the contact-welded rail template without surfacing showed: i) at the rolling surface of the rail head and in the weld zone there are plastic deformation of the structure of the weld metal, cracks and chips formed during operation; ii) increased hardness at the rolling surface is caused by plastic deformation; iii) quenching structures in the weld zone are not detected
The pilot samples with defects of wrinkling and wear of the rail head in the weld zone repaired by electric arc surfacing meet the criteria of static strength, such as the breaking load and deflection of the specimen, to the same degree as the rail samples without surfacing

Summary

Introduction

The railways of Russia have over 92 thousand km of a continuous track, which has about 10 million welded rail joints. Considerable deformations and temperatures of the weld zone occur in the surface layers of the rail head. They lead to changes in the structure and properties of the metal and reduce the contact strength and wear resistance of the rails [6,7,8,9]. The number of rail breaks in the weld area increases This determines the relevance of improving the methods of restoring damaged rails and improving their operational properties [10,11]. In order to develop technologies to eliminate crumple and wear of rails in the zone of an electriccontact welded joint, studies were carried out that were performed in one and two layers using electric arc surfacing

Research

Results

Conclusion