1.
DT - Výhybkárna a strojírna, a.s.
Dolní 3137/100, 797 11 Prostějov, Česká republika
www.dtvm.cz, e-mail: dt@dtvm.cz
EN ISO 9001
EN ISO 3834-2
EN ISO 14001
OHSAS 18001
WEAR OF THE RAILWAY TURNOUT
CROSSINGS MADE OF EXPLOSIVE
HARDENED HADFIELD STEEL
Ing. Petr Havlíček – Ing. Josef Zbořil, Ph.D.
research project manager
METAL 2013, May 15th – 17th 2013, Brno, Czech Republic
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2.
Project TAČR - TA01031297
„Increasing the quality of track in switches by flexibility“
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Goals and expected practical use
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

3.
1. Introduction
1.1 Railway turnout crossing
1.2 Hadfield steel explosive hardening
2. Experiment
2.1 Surface hardness in the course of explosive hardening
2.2 Crossing in the track behavior monitoring
2.3 Surface hardness – development in the track
2.4 The rate of material loss
3. Results and discussion
4. Conclusions
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Content
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

4.
- The Hadfield steel is commonly applied across the world for the turnout
crossings manufacture, which are the most dynamic stressed
components in the railway turnouts
- After the crossing installation in situ was the re-checking carried out
within the regular periods
- The surface hardness measurement was the crossing upper running
table scanned via scanner HandyScan 3D EXAscan and software
Geomagic Qualify
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1. Introduction
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

5.
- The crossing is the dynamically most stressed part of the railway
turnout
- The crossing is extremely stressed with dynamic impacts and by means
of compressive and impact loads coming from the railway vehicle axles
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1.1 Railway turnout crossing
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

6.
- Brisant explosive stuff thickness 2 - 4 mm applied onto part surface
- Initiates high pressure impact wave (6 - 25 GPa)
- Defects in the metal crystal lattice (dislocations movement, inception of
deforming twins and slide dislocation lines)
- The explosive hardening increases also the sub-surface hardness into
depth 20 mm below the hardened surface
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1.2 Hadfield steel explosive hardening
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

7.
- The crossing made of Hadfield steel and equipped with explosive layer
type Semtex 10SE with thickness 2 mm
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1.2 Hadfield steel explosive hardening
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

8.
- The austenitic structure changes in the Hadfield steel after the
explosion hardening and as monitored within the framework of
operation
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1.2 Hadfield steel explosive hardening
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

9.
- Validation - instalation of the crossing into the Czech Republic railway
network
- Crossing was explosive hardened in December 2012
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2. Experiment
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

10.
- In the course of the crossing hardening the hardness was checked on
seven spots situated on the upper surface
- Resulting hardness must fulfill standard EN 15689
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2.1 Surface hardness in the course of explosive hardening
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

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- After the crossing installation into railway track the surface hardness
measurement was carried out within the regular intervals
- During every check of the crossing the upper running surface is scanned
by means of HandyScan 3D EXAscan
- The same measurement method was applied for the crossing installed
in situ in 2010, which was free from explosive hardening
- The selected period for both crossings checking takes into consideration
the possibility to compare crossings under the same loads applied and
expressed in million of gross tons – MGT
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2.2 Crossing in the track behavior monitoring
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

12.
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2.3 Surface hardness – development in the track
Wear of the railway turnout crossings made of explosive hardened Hadfield steel
150
250
350
450
550
0 1 2 3 4 5 6 7 8
Applied load [MGT]
Hardness[HBLD]
Crossing A (explosive hardened)
Crossing B (free from explosive hardening)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
0 1 2 3 4 5 6 7 8
Applied load [MGT]
Materialloss[mm]
Crossing A (explosive hardened)
Crossing B (free from explosive hardening)

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- In the same time during the surface hardness checking, the values of
the material loss (the wear) were recorded at the crossing selected
spots, which were found by means of checking rule and the wedge
application and via scanner HandyScan 3D EXAscan
- The material loss measurement results show that the wear of the
explosion hardened crossing is much lesser within the first stage of
operation when compared with crossing free from explosive hardening
(difference 1.4 mm under applied load 6.5 MGT)
- Thus we can say that the hardening allows the crossing dimensions
stabilizing, which may save the costs with respect to the maintenance
grinding or application of the missing material by welding on the upper
running surfaces
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2.4 The rate of material loss
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

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- The 3D scanner enables to depict the overall survey of the material loss
and increments in the shape of flow lips across the whole scanned area
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2.4 The rate of material loss
Wear of the railway turnout crossings made of explosive hardened Hadfield steel
nose of
the frog
wing rails

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- The 3D scanner enables to depict the overall survey of the material loss
and increments in the shape of flow lips across the whole scanned area
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2.4 The rate of material loss
Wear of the railway turnout crossings made of explosive hardened Hadfield steel
nose of
the frog
wing rails

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- The comparison of the data coming from the crossing A explosive
hardened surface inspection and the hardening-free crossing B proves
the assumption that the crossing B surface deformation hardening is a
quicker one
- Our case shows the values approximately 500 till 530 HBLD. The
positive assets are expected in the form of diminished loss of material,
which means the expected longer operational life
- Meanwhile it is confirmed by the wing rail material real loss when this
value in case of B crossing reached after application of load 6.5 MGT the
value 2.4 mm and in case crossing A only 1.0 mm
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3. Results and discussion
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

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- The regular monitoring of the surface hardness and the wear extent of
the explosive hardened crossings upper running surfaces, which are
installed into Railway Tracks and its comparison with crossings free from
explosive hardening yields important information on crossings behavior
and features
- It is possible to say the monitored explosive hardened crossing proves so
far the prominent savings on material of the upper running area,
specifically savings of 1.4 mm at assessed spot under applied load of 6.5
MGT
- Its installation is supposed in 2014 and the installation of explosive
hardened crossings is the one of intended variants.
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4. Conclusions
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

18.
1. Fremunt, P., Podrábský, T.: Konstrukční oceli, 1996
2. Havlíček, P., Bušová, K.: Experience with explosive hardening of railway
crossings made of Hadfield steel, 2012
3. Li, M., Zhao, S.: Explosive hardening of high Mn steel, 1991
4. Liu, F.C., Lv, B., Zhang, F.C., Yang, S.: Enhanced work hardening in
Hadfield steel during explosive treatment, 2011
5. Nesvadba, P.: Application of sheet explosive for metal hardening, 2004
6. Havlíček, P., Nesvadba, P.: Application of explosive hardening on
railway infrastructure parts, 2011
7. Havlíček, P., Navrátil, P.: Využití 3D skeneru pro hodnocení opotřebení
dílů výhybek, 2013
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References
Wear of the railway turnout crossings made of explosive hardened Hadfield steel

19.
Thank You for Your attention
Ing. Josef Zbořil, Ph.D.
research project manager
zborilj@dtvm.cz
DT - Výhybkárna a strojírna a.s., Prostějov
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Wear of the railway turnout crossings made of explosive hardened Hadfield steel