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WEAR OF THE RAILWAY TURNOUT CROSSINGS MADE OF EXPLOSIVE HARDENED HADFIELD STEEL

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Presentation in METAL 2013, Brno, Czech republic, May 15th - 17th 2013

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WEAR OF THE RAILWAY TURNOUT CROSSINGS MADE OF EXPLOSIVE HARDENED HADFIELD STEEL

  1. 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 1
  2. 2. Project TAČR - TA01031297 „Increasing the quality of track in switches by flexibility“ 2 Goals and expected practical use Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  3. 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 3 Content Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  4. 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 4 1. Introduction Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  5. 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 5 1.1 Railway turnout crossing Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  6. 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 6 1.2 Hadfield steel explosive hardening Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  7. 7. - The crossing made of Hadfield steel and equipped with explosive layer type Semtex 10SE with thickness 2 mm 7 1.2 Hadfield steel explosive hardening Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  8. 8. - The austenitic structure changes in the Hadfield steel after the explosion hardening and as monitored within the framework of operation 8 1.2 Hadfield steel explosive hardening Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  9. 9. - Validation - instalation of the crossing into the Czech Republic railway network - Crossing was explosive hardened in December 2012 9 2. Experiment Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  10. 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 10 2.1 Surface hardness in the course of explosive hardening Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  11. 11. - 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 11 2.2 Crossing in the track behavior monitoring Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  12. 12. 12 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)
  13. 13. - 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 13 2.4 The rate of material loss Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  14. 14. - 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 14 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
  15. 15. - 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 15 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
  16. 16. - 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 16 3. Results and discussion Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  17. 17. - 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. 17 4. Conclusions Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  18. 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 18 References Wear of the railway turnout crossings made of explosive hardened Hadfield steel
  19. 19. Thank You for Your attention Ing. Josef Zbořil, Ph.D. research project manager zborilj@dtvm.cz DT - Výhybkárna a strojírna a.s., Prostějov 19 Wear of the railway turnout crossings made of explosive hardened Hadfield steel

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