Structure and properties of rails after extremely long-term operation

The paper reveals regularities and mechanisms of structure-phase states and properties formation of of differentially hardened 100-m rails of DT 350 category after the passed tonnage of 1411 mln. tons brutto. The formation of highly defective surface layer with nanosize (40–50 nm) grain-subgrain structure of pearlite colonies and submicrocrystal (150–250 nm) structure grains with structure free ferrite is detected. The change of hardness, microhardness, crystal lattice parameter, microdistorsion level, scalar and excess dislocation density on the rails head section are analyzed. The possible mechanisms of cementite plates’ transformation at extremely long-term operation are discussed.

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Structure-phase states and properties of rail tread surface at long-term operation

Izvestiya vysshikh uchebnykh zavedenii. Fizika ◽

10.17223/00213411/64/1/71 ◽

2021 ◽

Vol 64 (1) ◽

pp. 71-77

Author(s):

Yu.F. Ivanov ◽

◽

V.E. Kormyshev ◽

V.E. Gromov ◽

A.A. Yuriev ◽

...

Keyword(s):

Material Science ◽

Lattice Parameter ◽

Crystal Lattice Parameter ◽

Subgrain Structure ◽

Term Operation ◽

Structure Phase ◽

Multiple Transformation ◽

Lamellar Pearlite ◽

Differentially Quenched Rails

Using the methods of modern physical material science the investigations of structure-phase states and properties at different depth from tread surface of differentially quenched rails at extremely long-term operation (passed tonnage 1411 mln t) are carried out. The hardness decrease from 37.1 to 35.8 HRC at the depth 2 and 10 mm and microhardness from 1481 to 1210 MPa, respectively is revealed. The established multiple transformation of tread surface structure concludes in: fracture of lamellar pearlite structure and subgrain structure formation of submicronsizes (100-150 nm); precipitation of carbide phase nanoparticles (30-55 nm)along the boundaries and in the volume ofsubgrains; growth of microdistorsions and α-Fe crystal lattice parameter; growth of scalar and excess dislocation density. The suggestions about the possible reasons of observable regularities are made.

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Long-term operation of rail steel: Degradation of structure and properties of surface layer

Journal of Surface Investigation X-ray Synchrotron and Neutron Techniques ◽

10.1134/s1027451016050281 ◽

2016 ◽

Vol 10 (5) ◽

pp. 1101-1105 ◽

Cited By ~ 9

Author(s):

V. E. Gromov ◽

Yu. F. Ivanov ◽

K. V. Morozov ◽

O. A. Peregudov ◽

O. A. Semina

Keyword(s):

Surface Layer ◽

Rail Steel ◽

Structure And Properties ◽

Term Operation ◽

Degradation Of Structure

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Degradation of structure and properties of rail surface layer at long-term operation

Materials Science and Technology ◽

10.1080/02670836.2017.1287983 ◽

2017 ◽

Vol 33 (12) ◽

pp. 1473-1478 ◽

Cited By ~ 3

Author(s):

V. E. Gromov ◽

Yu. F. Ivanov ◽

R. S. Qin ◽

O. A. Peregudov ◽

K. V. Aksenova ◽

...

Keyword(s):

Surface Layer ◽

Structure And Properties ◽

Term Operation ◽

Degradation Of Structure

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Structure and properties of differentially hardened 100-m rails after long-term operation

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/866/1/012053 ◽

2020 ◽

Vol 866 ◽

pp. 012053

Author(s):

V E Kormyshev ◽

E V Polevoy ◽

A V Golovatenko ◽

V E Gromov ◽

Yu F Ivanov ◽

...

Keyword(s):

Structure And Properties ◽

Term Operation

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Physical Nature of Strengthening Mechanisms During Extremely Long-Term Operation of Rails

Izvestiya of Altai State University ◽

10.14258/izvasu(2021)1-05 ◽

2021 ◽

pp. 33-39

Author(s):

Yu.F. Ivanov ◽

A.A. Yuriev ◽

V.E. Kormyshev ◽

X. Chen ◽

V.B. Kosterev ◽

...

Keyword(s):

Surface Layer ◽

Relative Content ◽

Formation Mechanisms ◽

Strengthening Mechanisms ◽

Near Surface ◽

Term Operation ◽

Rail Head ◽

Metal Volume ◽

Lamellar Pearlite

The quantitative estimation of strengthening mechanisms of rails’ surface layer is carried out on the basis of regularities and formation mechanisms of structure-phase states revealed by the methods of modern physical materials science. It is performed at different depths of the rail head along the central axis and fillet of differentially quenched 100-meter rails after the extremely long-term operation (gross passed tonnage of 1411 mln tons). A long-term operation of rails is accompanied by the formation of structural constituent gradient consisting of a regular change in the relative content of lamellar pearlite, fractured pearlite, the structure of ferrite-carbide mixture, scalar, and excess dislocation density along the cross-section of the rail head. As the distance to the rail fillet surface decreases, the relative content of metal volume with lamellar pearlite decreases. However, the relative content of metal volume with the presence of the fractured pearlite structure and ferrite-carbide mixture increases. The contributions caused by the matrix lattice friction, intraphase boundaries, dislocation substructure, presence of carbide particles, internal stress fields, solid-solution strengthening, pearlite component of steel structure are estimated. It is shown that the main mechanism of strengthening in the surface layer is due to the interaction of moving dislocations with low-angle boundaries of nanometer dimensional fragments and subgrains. The main dislocation strengthening mechanism in a near-surface layer at a depth of 2-10 mm is due to the interaction of moving dislocations with immobile ones.

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