|
|
Microstructure and hardness of bainitic weld deposits on rails
Havlík, Petr ; Stránský, Karel (referee) ; Foret, Rudolf (advisor)
Surfacing worn crane railways as renovation technology can make several possible ways, so as manual welding whit coated electrode, with filled electrode or automatic submerged arc. The resulting mechanical properties will depend on the additional materials, which was used to create surfacing. This thesis deals whit evaluation of integrity and microstructure single - layer to three - layer surfacing with filled electrode on the rail with predominantly pearlitic structure. Were evaluated areas with the greatest heat dissipation during cooling, due to the possible occurrence of side structures. The study employed the interaction light microscopy, the scanning electron microscopy equipped by energy dispersive chemical microanalysis, the macro and micro hardness measurement by Vickers.
|
|
|
Microstructure and hardness of bainitic weld deposits on rails
Havlík, Petr ; Stránský, Karel (referee) ; Foret, Rudolf (advisor)
Surfacing worn crane railways as renovation technology can make several possible ways, so as manual welding whit coated electrode, with filled electrode or automatic submerged arc. The resulting mechanical properties will depend on the additional materials, which was used to create surfacing. This thesis deals whit evaluation of integrity and microstructure single - layer to three - layer surfacing with filled electrode on the rail with predominantly pearlitic structure. Were evaluated areas with the greatest heat dissipation during cooling, due to the possible occurrence of side structures. The study employed the interaction light microscopy, the scanning electron microscopy equipped by energy dispersive chemical microanalysis, the macro and micro hardness measurement by Vickers.
|
|
|
Fracture behaviour of welds made of pearlitic and bainitic steel
Dlouhý, Ivo ; Holzmann, Miloslav ; Zbořil, J.
The paper is focused on microstructure evaluations, hardness and fracture behaviour analyses of welded joint made from newly developed cast bainitic Lo8CrNiMo steel and pearlitic rail steel of the type UIC 900A. Dynamic fracture toughness was evaluated based on data from precracked Charpy type specimens loaded by means of instrumented impact tester. The lowest dynamic fracture toughness values and consequently the higher risk of brittle fracture possesses the pearlitic steel UIC 900A and its HAZ. At application temperature range this steel is on lower shelf of ductile to brittle transition, the tempering in HAZ didnŽt affect the toughness substantially. The cast bainitic steel in joint is typical by two times higher toughness values comparing to pearlitic one, in HAZ further toughness increase may be expected. The weld zone itself is characterised by high scatter of toughness data, nevertheless, all the values are above the scatter band characterising the pearlitic steel.
|
guest ::
