APPLICATION OF SCANNING ELECTRONIC MICROSCOPY FOR METALLOGRAPHY OF WELDED JOINTS OF RAILS

DOI

10.2991/avent-18.2018.70How to use a DOI?

Keywords

microstructures; quenching; structure; electron microscope; perlite; ferrite

Abstract

The results of a study of the change in the microstructure of welded joints of rail steel are presented. Comparison of various methods of structural factor analysis is presented. Comparative studies of various methods of analyzing the structural factor in welded joints of K76F rail steels according to GOST R 51685-2013 are considered. It has been established that for this series of experiments, a decrease in hardness of the surface of the welded joint, as well as an increase in Barkhausen MP noise, is 65-75% of the mean value. That indicates the presence of tensile residual stresses in this zone. A coarse-grained structure of primary austenite grains with a grain score of 2 ... 3 is observed along the joint line and adjacent metal layers. A solid grid of ferrite precipitates is clearly observed along the grain boundaries of the primary austenite that indicates the low plastic properties of this section. As a result of conducted studies, it was found that the microstructure of the metal in the heat affected zone of the welded rail joint after the flash welding is represented by plate and globular perlite. The change in hardness in the heat affected zone is associated with a change in the interlamellar distance of perlite that in turn depends on the cooling conditions, i.e. thermal cycle of welding. Control of the thermal cycle during butt flash welding of rails will allow one to form the optimal structure in the welded joint.

Copyright

© 2018, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

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TY  - CONF
AU  - M.G. Shtayger
AU  - V.V. Kondratiev
AU  - A.E. Balanovsky
AU  - A.I. Karlina
AU  - A.S. Govorkov
PY  - 2018/05
DA  - 2018/05
TI  - APPLICATION OF SCANNING ELECTRONIC MICROSCOPY FOR METALLOGRAPHY OF WELDED JOINTS OF RAILS
BT  - Proceedings of the International Conference "Aviamechanical engineering and transport" (AVENT 2018)
PB  - Atlantis Press
SP  - 360
EP  - 364
SN  - 2352-5401
UR  - https://doi.org/10.2991/avent-18.2018.70
DO  - 10.2991/avent-18.2018.70
ID  - Shtayger2018/05
ER  -